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  • 1.
    Perdigon-Toro, Lorena
    et al.
    Univ Potsdam, Germany.
    Zhang, Huotian
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Markina, Anastaa si
    Max Planck Inst Polymer Res, Germany.
    Yuan, Jun
    Cent S Univ, Peoples R China.
    Hosseini, Seyed Mehrdad
    Univ Potsdam, Germany.
    Wolff, Christian M.
    Univ Potsdam, Germany.
    Zuo, Guangzheng
    Univ Potsdam, Germany.
    Stolterfoht, Martin
    Univ Potsdam, Germany.
    Zou, Yingping
    Cent S Univ, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Andrienko, Denis
    Max Planck Inst Polymer Res, Germany.
    Shoaee, Safa
    Univ Potsdam, Germany.
    Neher, Dieter
    Univ Potsdam, Germany.
    Barrierless Free Charge Generation in the High-Performance PM6:Y6 Bulk Heterojunction Non-Fullerene Solar Cell2020Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, artikel-id 1906763Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Organic solar cells are currently experiencing a second golden age thanks to the development of novel non-fullerene acceptors (NFAs). Surprisingly, some of these blends exhibit high efficiencies despite a low energy offset at the heterojunction. Herein, free charge generation in the high-performance blend of the donor polymer PM6 with the NFA Y6 is thoroughly investigated as a function of internal field, temperature and excitation energy. Results show that photocurrent generation is essentially barrierless with near-unity efficiency, regardless of excitation energy. Efficient charge separation is maintained over a wide temperature range, down to 100 K, despite the small driving force for charge generation. Studies on a blend with a low concentration of the NFA, measurements of the energetic disorder, and theoretical modeling suggest that CT state dissociation is assisted by the electrostatic interfacial field which for Y6 is large enough to compensate the Coulomb dissociation barrier.

  • 2.
    Yang, Fei
    et al.
    Huazhong Univ Sci and Technol, Peoples R China.
    Chen, Hongting
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Huazhong Univ Sci and Technol, Peoples R China.
    Zhang, Rui
    Huazhong Univ Sci and Technol, Peoples R China.
    Liu, Xiaoke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Zhang, Weizhuo
    Huazhong Univ Sci and Technol, Peoples R China.
    Zhang, JiBin
    Huazhong Univ Sci and Technol, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Wang, Lei
    Huazhong Univ Sci and Technol, Peoples R China.
    Efficient and Spectrally Stable Blue Perovskite Light-Emitting Diodes Based on Potassium Passivated Nanocrystals2020Ingår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, artikel-id 1908760Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Metal halide perovskites have aroused tremendous interest in the past several years for their promising applications in display and lighting. However, the development of blue perovskite light-emitting diodes (PeLEDs) still lags far behind that of their green and red cousins due to the difficulty in obtaining high-quality blue perovskite emissive layers. In this study, a simple approach is conceived to improve the emission and electrical properties of blue perovskites. By introducing an alkali metal ion to occupy some sites of peripheral suspended organic ligands, the nonradiative recombination is suppressed, and, consequently, blue CsPb(Br/Cl)(3) nanocrystals with a high photoluminescence quantum efficiency of 38.4% are obtained. The introduced K+ acts as a new type of metal ligand, which not only suppresses nonradiative pathways but also improves the charge carrier transport of the perovskite nanocrystals. With further engineering of the device structure to balance the charge injection rate, a spectrally stable and efficient blue PeLED with a maximum external quantum efficiency of 1.96% at the emission peak of 477 nm is fabricated.

  • 3.
    Wu, Tian
    et al.
    Soochow Univ, Peoples R China.
    Li, Junnan
    Soochow Univ, Peoples R China.
    Zou, Yatao
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Soochow Univ, Peoples R China.
    Xu, Hao
    Soochow Univ, Peoples R China.
    Wen, Kaichuan
    Soochow Univ, Peoples R China; Nanjing Tech Univ Nanjing Tech, Peoples R China; Nanjing Tech Univ Nanjing Tech, Peoples R China.
    Wan, Shanshan
    Soochow Univ, Peoples R China.
    Bai, Sai
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Song, Tao
    Soochow Univ, Peoples R China.
    McLeod, John A.
    Soochow Univ, Peoples R China.
    Duhm, Steffen
    Soochow Univ, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Sun, Baoquan
    Soochow Univ, Peoples R China.
    High-Performance Perovskite Light-Emitting Diode with Enhanced Operational Stability Using Lithium Halide Passivation2020Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Defect passivation has been demonstrated to be effective in improving the radiative recombination of charge carriers in perovskites, and consequently, the device performance of the resultant perovskite light-emitting diodes (LEDs). State-of-the-art useful passivation agents in perovskite LEDs are mostly organic chelating molecules that, however, simultaneously sacrifice the charge-transport properties and thermal stability of the resultant perovskite emissive layers, thereby deteriorating performance, and especially the operational stability of the devices. We demonstrate that lithium halides can efficiently passivate the defects generated by halide vacancies and reduce trap state density, thereby suppressing ion migration in perovskite films. Efficient green perovskite LEDs based on all-inorganic CsPbBr3 perovskite with a peak external quantum efficiency of 16.2 %, as well as a high maximum brightness of 50 270 cd m(-2), are achieved. Moreover, the device shows decent stability even under a brightness of 10(4) cd m(-2). We highlight the universal applicability of defect passivation using lithium halides, which enabled us to improve the efficiency of blue and red perovskite LEDs.

  • 4.
    Zhou, Zichun
    et al.
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Liu, Wenrui
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Zhou, Guanqing
    Shanghai Jiao Tong Univ, Peoples R China.
    Zhang, Ming
    Shanghai Jiao Tong Univ, Peoples R China.
    Qian, Deping
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Zhang, Jianyun
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Chen, Shanshan
    Chongqing Univ, Peoples R China; Ulsan Natl Inst Sci and Technol, South Korea.
    Xu, Shengjie
    Chinese Acad Sci, Peoples R China.
    Yang, Changduk
    Ulsan Natl Inst Sci and Technol, South Korea.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Zhu, Haiming
    Zhejiang Univ, Peoples R China.
    Liu, Feng
    Shanghai Jiao Tong Univ, Peoples R China.
    Zhu, Xiaozhang
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Subtle Molecular Tailoring Induces Significant Morphology Optimization Enabling over 16% Efficiency Organic Solar Cells with Efficient Charge Generation2020Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, artikel-id 1906324Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Manipulating charge generation in a broad spectral region has proved to be crucial for nonfullerene-electron-acceptor-based organic solar cells (OSCs). 16.64% high efficiency binary OSCs are achieved through the use of a novel electron acceptor AQx-2 with quinoxaline-containing fused core and PBDB-TF as donor. The significant increase in photovoltaic performance of AQx-2 based devices is obtained merely by a subtle tailoring in molecular structure of its analogue AQx-1. Combining the detailed morphology and transient absorption spectroscopy analyses, a good structure-morphology-property relationship is established. The stronger pi-pi interaction results in efficient electron hopping and balanced electron and hole mobilities attributed to good charge transport. Moreover, the reduced phase separation morphology of AQx-2-based bulk heterojunction blend boosts hole transfer and suppresses geminate recombination. Such success in molecule design and precise morphology optimization may lead to next-generation high-performance OSCs.

  • 5.
    Yao, Huifeng
    et al.
    Chinese Acad Sci, Peoples R China.
    Cui, Yong
    Univ Chinese Acad Sci, Peoples R China.
    Qian, Deping
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Ponseca, Carlito
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Honarfar, Alireza
    Lund Univ, Sweden.
    Xu, Ye
    Univ Chinese Acad Sci, Peoples R China.
    Xin, Jingming
    Xi An Jiao Tong Univ, Peoples R China.
    Chen, Zhenyu
    Xi An Jiao Tong Univ, Peoples R China.
    Hong, Ling
    Univ Chinese Acad Sci, Peoples R China.
    Gao, Bowei
    Univ Chinese Acad Sci, Peoples R China.
    Yu, Runnan
    Univ Chinese Acad Sci, Peoples R China.
    Zu, Yunfei
    Univ Chinese Acad Sci, Peoples R China.
    Ma, Wei
    Xi An Jiao Tong Univ, Peoples R China.
    Chabera, Pavel
    Lund Univ, Sweden.
    Pullerits, Tonu
    Lund Univ, Sweden.
    Yartsev, Arkady
    Lund Univ, Sweden.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Hou, Jianhui
    Univ Chinese Acad Sci, Peoples R China.
    14.7% Efficiency Organic Photovoltaic Cells Enabled by Active Materials with a Large Electrostatic Potential Difference2019Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 141, nr 19, s. 7743-7750Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Although significant improvements have been achieved for organic photovoltaic cells (OPVs), the top-performing devices still show power conversion efficiencies far behind those of commercialized solar cells. One of the main reasons is the large driving force required for separating electron-hole pairs. Here, we demonstrate an efficiency of 14.7% in the single-junction OPV by using a new polymer donor PTO2 and a nonfullerene acceptor IT-4F. The device possesses an efficient charge generation at a low driving force. Ultrafast transient absorption measurements probe the formation of loosely bound charge pairs with extended lifetime that impedes the recombination of charge carriers in the blend. The theoretical studies reveal that the molecular electrostatic potential (ESP) between PTO2 and IT-4F is large, and the induced intermolecular electric field may assist the charge generation. The results suggest OPVs have the potential for further improvement by judicious modulation of ESP.

  • 6.
    Sun, Huiliang
    et al.
    Southern Univ Sci and Technol SUSTech, Peoples R China; Southern Univ Sci and Technol SUSTech, Peoples R China.
    Liu, Tao
    HKUST, Peoples R China.
    Yu, Jianwei
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Lau, Tsz-Ki
    Chinese Univ Hong Kong, Peoples R China.
    Zhang, Guangye
    eFlexPV Ltd, Peoples R China.
    Zhang, Yujie
    Southern Univ Sci and Technol SUSTech, Peoples R China; Southern Univ Sci and Technol SUSTech, Peoples R China.
    Su, Mengyao
    Southern Univ Sci and Technol SUSTech, Peoples R China; Southern Univ Sci and Technol SUSTech, Peoples R China.
    Tang, Yumin
    Southern Univ Sci and Technol SUSTech, Peoples R China; Southern Univ Sci and Technol SUSTech, Peoples R China.
    Ma, Ruijie
    HKUST, Peoples R China; HKUST, Peoples R China.
    Liu, Bin
    Southern Univ Sci and Technol SUSTech, Peoples R China; Southern Univ Sci and Technol SUSTech, Peoples R China.
    Liang, Jiaen
    HKUST, Peoples R China; HKUST, Peoples R China.
    Feng, Kui
    Southern Univ Sci and Technol SUSTech, Peoples R China; Southern Univ Sci and Technol SUSTech, Peoples R China.
    Lu, Xinhui
    Chinese Univ Hong Kong, Peoples R China.
    Guo, Xugang
    Southern Univ Sci and Technol SUSTech, Peoples R China; Southern Univ Sci and Technol SUSTech, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Yan, He
    HKUST, Peoples R China; HKUST, Peoples R China.
    A monothiophene unit incorporating both fluoro and ester substitution enabling high-performance donor polymers for non-fullerene solar cells with 16.4% efficiency2019Ingår i: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 12, nr 11, s. 3328-3337Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thiophene and its derivatives have been extensively used in organic electronics, particularly in the field of polymer solar cells (PSCs). Significant research efforts have been dedicated to modifying thiophene-based units by attaching electron-donating or withdrawing groups to tune the energy levels of conjugated materials. Herein, we report the design and synthesis of a novel thiophene derivative, FE-T, featuring a monothiophene functionalized with both an electron-withdrawing fluorine atom (F) and an ester group (E). The FE-T unit possesses distinctive advantages of both F and E groups, the synergistic effects of which enable significant downshifting of the energy levels and enhanced aggregation/crystallinity of the resulting organic materials. Shown in this work are a series of polymers obtained by incorporating the FE-T unit into a PM6 polymer to fine-tune the energetics and morphology of this high-performance PSC material. The optimal polymer in the series shows a downshifted HOMO and an improved morphology, leading to a high PCE of 16.4% with a small energy loss (0.53 eV) enabled by the reduced non-radiative energy loss (0.23 eV), which are among the best values reported for non-fullerene PSCs to date. This work shows that the FE-T unit is a promising building block to construct donor polymers for high-performance organic photovoltaic cells.

  • 7.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    A New Acceptor for Highly Efficient Organic Solar Cells2019Ingår i: JOULE, ISSN 2542-4351, Vol. 3, nr 4, s. 908-909Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Research into organic solar cells has gone from pure scientific curiosity to a topic of commercial relevance in the past few years, as a result of rapid development of non-fullerene acceptors. This transition is mainly driven by the development of new materials. Recently in Joule, Zou and co-workers developed a new acceptor material and reached a record efficiency for single-junction organic solar cells.

  • 8.
    Zhou, Ruimin
    et al.
    Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China; Univ Copenhagen, Denmark; Univ Copenhagen, Denmark.
    Jiang, Zhaoyan
    Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Yang, Chen
    Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Yu, Jianwei
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Feng, Jirui
    Xi An Jiao Tong Univ, Peoples R China.
    Adil, Muhammad Abdullah
    Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Deng, Dan
    Natl Ctr Nanosci and Technol, Peoples R China.
    Zou, Wenjun
    Natl Ctr Nanosci and Technol, Peoples R China.
    Zhang, Jianqi
    Natl Ctr Nanosci and Technol, Peoples R China.
    Lu, Kun
    Natl Ctr Nanosci and Technol, Peoples R China.
    Ma, Wei
    Xi An Jiao Tong Univ, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Wei, Zhixiang
    Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    All-small-molecule organic solar cells with over 14% efficiency by optimizing hierarchical morphologies2019Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, artikel-id 5393Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The high efficiency all-small-molecule organic solar cells (OSCs) normally require optimized morphology in their bulk heterojunction active layers. Herein, a small-molecule donor is designed and synthesized, and single-crystal structural analyses reveal its explicit molecular planarity and compact intermolecular packing. A promising narrow bandgap small-molecule with absorption edge of more than 930 nm along with our home-designed small molecule is selected as electron acceptors. To the best of our knowledge, the binary all-small-molecule OSCs achieve the highest efficiency of 14.34% by optimizing their hierarchical morphologies, in which the donor or acceptor rich domains with size up to ca. 70 nm, and the donor crystals of tens of nanometers, together with the donor-acceptor blending, are proved coexisting in the hierarchical large domain. All-small-molecule photovoltaic system shows its promising for high performance OSCs, and our study is likely to lead to insights in relations between bulk heterojunction structure and photovoltaic performance.

  • 9.
    Kumawat, Naresh Kumar
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Liu, Xiaoke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Kabra, Dinesh
    Indian Inst Technol, India.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Blue perovskite light-emitting diodes: progress, challenges and future directions2019Ingår i: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 11, nr 5, s. 2109-2120Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Metal halide perovskites have excellent optical and electrical properties and can be easily processed via low-cost solution-based techniques like blade-coating and inkjet printing, promising a bright future for various optoelectronic applications. Recently, encouraging progress has been made in perovskite light-emitting diodes (PeLEDs). Green, red, and near-infrared PeLEDs have achieved high external quantum efficiencies of more than 20%. However, as historically blue electroluminescence remains challenging in all previous LED technologies, we are witnessing a similar case with the development of blue PeLEDs, an essential part of displays and solid-state lighting, which lag far behind those of their counterparts. Herein, we review the recent progress of blue PeLEDs and discuss the main challenges including colour instability, poor photoluminescence efficiency and emission quenching by interlayers. Future directions are provided to facilitate the development of efficient blue PeLEDs.

  • 10.
    Zhang, Liangdong
    et al.
    Nanjing Tech Univ, Peoples R China.
    Jiang, Tao
    Nanjing Tech Univ, Peoples R China.
    Yi, Chang
    Nanjing Tech Univ, Peoples R China.
    Wu, Jiquan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Liu, Xiaoke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    He, Yaron
    Nanjing Tech Univ, Peoples R China.
    Miao, Yanfeng
    Nanjing Tech Univ, Peoples R China.
    Zhang, Ya
    Nanjing Tech Univ, Peoples R China.
    Zhang, Huotian
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Xie, Xinrui
    Zhejiang Univ, Peoples R China.
    Wang, Peng
    Zhejiang Univ, Peoples R China.
    Li, Renzhi
    Nanjing Tech Univ, Peoples R China; Nanjing Tech Univ, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Huang, Wei
    Nanjing Tech Univ, Peoples R China; Nanjing Tech Univ, Peoples R China; NPU, Peoples R China.
    Wang, Jianpu
    Nanjing Tech Univ, Peoples R China.
    Bright Free Exciton Electroluminescence from Mn-Doped Two-Dimensional Layered Perovskites2019Ingår i: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 10, nr 11, s. 3171-3175Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two-dimensional (2D) perovskites incorporating hydrophobic organic spacer cations show improved film stability and morphology compared to their three-dimensional (3D) counterparts. However, 2D perovskites usually exhibit low photoluminescence quantum efficiency (PLQE) owing to strong exciton-phonon interaction at room temperature, which limits their efficiency in light-emitting diodes (LEDs). Here, we demonstrate that the device performance of 2D perovskite LEDs can be significantly enhanced by doping Mn(2+)in (benzimidazolium)(2)PbI4 2D perovskite films to suppress the exciton-phonon interaction. The distorted [PbI6](4-) octahedra by Mn-doping and the rigid benzimidazolium (BIZ) ring without branched chains in the 2D perovskite structure lead to improved crystallinity and rigidity of the perovskites, resulting in suppressed phonon-exciton interaction and enhanced PLQE. On the basis of this strategy, for the first time, we report yellow electroluminescence from free excitons in 2D (n = 1) perovskites with a maximum brightness of 225 cd m(-2) and a peak EQE of 0.045%.

    Publikationen är tillgänglig i fulltext från 2020-05-23 13:52
  • 11.
    Hopper, Thomas R.
    et al.
    Imperial Coll London, England.
    Qian, Deping
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Yang, Liyan
    Chinese Acad Sci, Peoples R China.
    Wang, Xiaohui
    Xi An Jiao Tong Univ, Peoples R China.
    Zhou, Ke
    Xi An Jiao Tong Univ, Peoples R China.
    Kumar, Rhea
    Imperial Coll London, England.
    Ma, Wei
    Xi An Jiao Tong Univ, Peoples R China.
    He, Chang
    Chinese Acad Sci, Peoples R China.
    Hou, Jianhui
    Chinese Acad Sci, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Bakulin, Artem A.
    Imperial Coll London, England.
    Control of Donor-Acceptor Photophysics through Structural Modification of a "Twisting" Push-Pull Molecule2019Ingår i: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 31, nr 17, s. 6860-6869Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In contemporary organic solar cell (OSC) research, small A-D-A molecules comprising electron donor (D) and acceptor (A) units are increasingly used as a means to control the optoelectronic properties of photovoltaic blends. Slight structural variations to these A-D-A molecules can result in profound changes to the performance of the OSCs. Herein, we study two A-D-A molecules, BTCN-O and BTCN-M, which are identical in structure apart from a subtle difference in the position of alkyl chains, which force the molecules to adopt different equilibrium conformations. These steric effects cause the respective molecules to work better as an electron donor and acceptor when blended with benchmark acceptor and donor materials (PC71BM and PBDB-T). We study the photophysics of these "D:A" blends and devices using a combination of steady-state and time-resolved spectroscopic techniques. Time-resolved photoluminescence reveals the impact of the molecular conformation on the quenching of the A-D-A emission when BTCN-O and BTCN-M are blended with PBDB-T or PC71BM. Ultrafast broadband transient absorption spectroscopy demonstrates that the dynamics of charge separation are essentially identical when comparing BTCN-M and BTCN-O based blends, but the recombination dynamics are quite dissimilar. This suggests that the device performance is ultimately determined by the morphology of the blends imposed by the A-D-A conformation. This notion is supported by X-ray scattering measurements on the "D:A" films, electroluminescence data, and pump-push-photocurrent spectroscopy on the "D:A" devices. Our findings provide insight into the remarkable structure-function relationship in A-D-A molecules and emphasize the need for careful morphological and energetic considerations when designing high-performance OSCs.

  • 12.
    Jia, Xue
    et al.
    Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Zuo, Chuantian
    CSIRO Mfg, Australia.
    Tao, Shuxia
    Eindhoven Univ Technol, Netherlands.
    Sun, Kuan
    Chongqing Univ, Peoples R China.
    Zhao, Yixin
    Shanghai Jiao Tong Univ, Peoples R China.
    Yang, Shangfeng
    Univ Sci and Technol China, Peoples R China.
    Cheng, Ming
    Jiangsu Univ, Peoples R China.
    Wang, Mingkui
    Huazhong Univ Sci and Technol, Peoples R China.
    Yuan, Yongbo
    Cent S Univ, Peoples R China.
    Yang, Junliang
    Cent S Univ, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Xing, Guichuan
    Univ Macau, Peoples R China.
    Wei, Zhanhua
    Huaqiao Univ, Peoples R China.
    Zhang, Lijun
    Jilin Univ, Peoples R China.
    Yip, Hin-Lap
    South China Univ Technol, Peoples R China.
    Liu, Mingzhen
    Univ Elect Sci and Technol China, Peoples R China.
    Shen, Qing
    Univ Electrocommun, Japan.
    Yin, Longwei
    Shandong Univ, Peoples R China.
    Han, Liyuan
    Shanghai Jiao Tong Univ, Peoples R China.
    Liu, Shengzhong
    Shaanxi Normal Univ, Peoples R China.
    Wang, Lianzhou
    Univ Queensland, Australia.
    Luo, Jingshan
    Nankai Univ, Peoples R China.
    Tan, Hairen
    Nanjing Univ, Peoples R China.
    Jin, Zhiwen
    Lanzhou Univ, Peoples R China.
    Ding, Liming
    Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    CsPb(IxBr1-x)(3) solar cells2019Ingår i: SCIENCE BULLETIN, ISSN 2095-9273, Vol. 64, nr 20, s. 1532-1539Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell (PSC) becomes a promising candidate for next-generation high-efficiency solar cells. The power conversion efficiency (PCE) has boosted from 3.8% to 25.2% over the past ten years. Despite the rapid progress in PCE, the device stability is a key issue that impedes the commercialization of PSCs. Recently, all-inorganic cesium lead halide perovskites have attracted much attention due to their better stability compared with their organic-inorganic counterpart. In this progress report, we summarize the properties of CsPb(IxBr1-x)(3) and their applications in solar cells. The current challenges and corresponding solutions are discussed. Finally, we share our perspectives on CsPb(IxBr1-x)(3) solar cells and outline possible directions to further improve the device performance. (C) 2019 Science China Press. Published by Elsevier B.V. and Science China Press. All rights reserved.

  • 13.
    Ke, You
    et al.
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Wang, Nana
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Kong, Decheng
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Cao, Yu
    Nanjing Tech Univ NanjingTech, Peoples R China.
    He, Yarong
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Zhu, Lin
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Wang, Yuming
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Xue, Chen
    Northwestern Polytech Univ, Peoples R China.
    Peng, Qiming
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Huang, Wei
    Nanjing Tech Univ NanjingTech, Peoples R China; Northwestern Polytech Univ, Peoples R China.
    Wang, Jianpu
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Defect Passivation for Red Perovskite Light-Emitting Diodes with Improved Brightness and Stability2019Ingår i: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 10, nr 3, s. 380-385Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Efficient and stable red perovskite light-emitting diodes (PeLEDs) are important for realizing full-color display and lighting. Red PeLEDs can be achieved either by mixed-halide or low-dimensional perovskites. However, the device performance, especially the brightness, is still low owing to phase separation or poor charge transport issues. Here, we demonstrate red PeLEDs based on three-dimensional (3D) mixed-halide perovskites where the defects are passivated by using 5-aminovaleric acid. The red PeLEDs with an emission peak at 690 nm exhibit an external quantum efficiency of 8.7% and a luminance of 1408 cd m(-2). A maximum luminance of 8547 cd m(-2) can be further achieved as tuning the emission peak to 662 nm, representing the highest brightness of red PeLEDs. Moreover, those LEDs exhibit a half-life of up to 8 h under a high constant current density of 100 mA cm(-2), which is over 10 times improvement compared to literature results.

  • 14.
    Yu, Liyang
    et al.
    Sichuan Univ, Peoples R China; Chalmers Univ Technol, Sweden.
    Qian, Deping
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Marina, Sara
    Univ Basque Country, Spain; Univ Basque Country, Spain.
    Nugroho, Ferry A. A.
    Chalmers Univ Technol, Sweden.
    Sharma, Anirudh
    Flinders Univ S Australia, Australia; Univ Bordeaux, France.
    Hultmark, Sandra
    Chalmers Univ Technol, Sweden.
    Hofmann, Anna I.
    Chalmers Univ Technol, Sweden.
    Kroon, Renee
    Chalmers Univ Technol, Sweden.
    Benduhn, Johannes
    Tech Univ Dresden, Germany; Tech Univ Dresden, Germany.
    Smilgies, Detlef-M.
    CHESS, NY 14850 USA.
    Vandewal, Koen
    Hasselt Univ, Belgium.
    Andersson, Mats R.
    Flinders Univ S Australia, Australia.
    Langhammer, Christoph
    Chalmers Univ Technol, Sweden.
    Martin, Jaime
    Univ Basque Country, Spain; Univ Basque Country, Spain; Ikerbasque, Spain.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Mueller, Christian
    Chalmers Univ Technol, Sweden.
    Diffusion-Limited Crystallization: A Rationale for the Thermal Stability of Non-Fullerene Solar Cells2019Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, nr 24, s. 21766-21774Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Organic solar cells are thought to suffer from poor thermal stability of the active layer nanostructure, a common belief that is based on the extensive work that has been carried out on fullerene-based systems. We show that a widely studied non-fullerene acceptor, the indacenodithienothiophene-based acceptor ITIC, crystallizes in a profoundly different way as compared to fullerenes. Although fullerenes are frozen below the glass-transition temperature T-g of the photovoltaic blend, ITIC can undergo a glass-crystal transition considerably below its high T-g of similar to 180 degrees C. Nanoscopic crystallites of a low-temperature polymorph are able to form through a diffusion-limited crystallization process. The resulting fine-grained nanostructure does not evolve further with time and hence is characterized by a high degree of thermal stability. Instead, above T-g, the low temperature polymorph melts, and micrometer-sized crystals of a high-temperature polymorph develop, enabled by more rapid diffusion and hence long-range mass transport. This leads to the same detrimental decrease in photovoltaic performance that is known to occur also in the case of fullerene-based blends. Besides explaining the superior thermal stability of non-fullerene blends at relatively high temperatures, our work introduces a new rationale for the design of bulk heterojunctions that is not based on the selection of high-T-g materials per se but diffusion-limited crystallization. The planar structure of ITIC and potentially other non-fullerene acceptors readily facilitates the desired glass-crystal transition, which constitutes a significant advantage over fullerenes, and may pave the way for truly stable organic solar cells.

  • 15.
    Yu, Hongling
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Wang, Heyong
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Zhang, Jiangbin
    Univ Cambridge, England; Imperial Coll London, England.
    Lu, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Yuan, Zhongcheng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Xu, Weidong
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Nanjing Tech Univ, Peoples R China.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Bakulin, Artem A.
    Imperial Coll London, England.
    Friend, Richard H.
    Univ Cambridge, England.
    Wang, Jianpu
    Nanjing Tech Univ, Peoples R China.
    Liu, Xiaoke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Univ Cambridge, England.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Efficient and Tunable Electroluminescence from In Situ Synthesized Perovskite Quantum Dots2019Ingår i: Small, ISSN 1613-6810, E-ISSN 1613-6829, Vol. 15, nr 8, artikel-id 1804947Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Semiconductor quantum dots (QDs) are among the most promising next-generation optoelectronic materials. QDs are generally obtained through either epitaxial or colloidal growth and carry the promise for solution-processed high-performance optoelectronic devices such as light-emitting diodes (LEDs), solar cells, etc. Herein, a straightforward approach to synthesize perovskite QDs and demonstrate their applications in efficient LEDs is reported. The perovskite QDs with controllable crystal sizes and properties are in situ synthesized through one-step spin-coating from perovskite precursor solutions followed by thermal annealing. These perovskite QDs feature size-dependent quantum confinement effect (with readily tunable emissions) and radiative monomolecular recombination. Despite the substantial structural inhomogeneity, the in situ generated perovskite QDs films emit narrow-bandwidth emission and high color stability due to efficient energy transfer between nanostructures that sweeps away the unfavorable disorder effects. Based on these materials, efficient LEDs with external quantum efficiencies up to 11.0% are realized. This makes the technologically appealing in situ approach promising for further development of state-of-the-art LED systems and other optoelectronic devices.

  • 16.
    Cheng, Li-Peng
    et al.
    Soochow Univ, Peoples R China.
    Huang, Jing-Sheng
    Soochow Univ, Peoples R China.
    Shen, Yang
    Soochow Univ, Peoples R China.
    Li, Guo-Peng
    Hefei Univ Technol HFUT, Peoples R China.
    Liu, Xiaoke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Li, Wei
    Soochow Univ, Peoples R China.
    Wang, Yu-Han
    Soochow Univ, Peoples R China.
    Li, Yan-Qing
    Soochow Univ, Peoples R China.
    Jiang, Yang
    Hefei Univ Technol HFUT, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Lee, Chun-Sing
    City Univ Hong Kong, Peoples R China.
    Tang, Jian-Xin
    Soochow Univ, Peoples R China.
    Efficient CsPbBr3 Perovskite Light-Emitting Diodes Enabled by Synergetic Morphology Control2019Ingår i: Advanced Optical Materials, ISSN 2162-7568, E-ISSN 2195-1071, Vol. 7, nr 4, artikel-id 1801534Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The development of solution-processed inorganic metal halide perovskite light-emitting diodes (PeLEDs) is currently hindered by low emission efficiency due to morphological defects and severe non-radiative recombination in all-inorganic perovskite emitters. Herein, bright PeLEDs are demonstrated by synergetic morphology control over cesium lead bromide (CsPbBr3) perovskite films with the combination of two additives. The phenethylammonium bromide additive enables the formation of mixed-dimensional CsPbBr3 perovskites featuring the reduced grain size (amp;lt;15 nm) and efficient energy funneling, while the dielectric polyethyleneglycol additive promotes the formation of highly compact and pinhole-free perovskite films with defect passivation at grain boundaries. Consequently, green PeLEDs achieve a current efficiency of 37.14 cd A(-1) and an external quantum efficiency of 13.14% with the maximum brightness up to 45 990 cd m(-2) and high color purity. Furthermore, this method can be effectively extended to realize flexible PeLEDs on plastic substrates with a high efficiency of 31.0 cd A(-1).

  • 17.
    Li, Zhiqi
    et al.
    Jilin Univ, Peoples R China.
    Wang, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Liu, Chunyu
    Jilin Univ, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Shen, Liang
    Jilin Univ, Peoples R China.
    Guo, Wenbin
    Jilin Univ, Peoples R China.
    Efficient perovskite solar cells enabled by ion-modulated grain boundary passivation with a fill factor exceeding 84%2019Ingår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, nr 39, s. 22359-22365Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Alkali metal cation modulation toward high-electronic-quality perovskite films requires strict control over trap densities in the devices. By introducing tailor-made potassium cation (K+)-functionalized carbon nanodots (CNDs@K) into the perovskite precursor solution, we succeeded in defect passivation and crystallization control of the perovskite film. X-ray diffraction indicated that the binding effect of carbon dots confined the K+ ions in the grain boundary and prevented excessive cations from occupying interstitial sites, thereby reducing the microstrain of the polycrystalline film. Consequently, the synergistic effect of the tailored crystal size and suppressed grain boundary defects could reduce the charge trap density, facilitate charge generation, and lengthen the carrier lifetime, leading to a boosted efficiency of 21.01% with a high fill factor of 84%. This performance is among the best reported for carbon dot-doped PSCs.

  • 18.
    Yuan, Jun
    et al.
    Univ Calif Los Angeles, CA 90095 USA; Cent S Univ, Peoples R China; Univ Calif Los Angeles, CA 90095 USA.
    Huang, Tianyi
    Univ Calif Los Angeles, CA 90095 USA.
    Cheng, Pei
    Univ Calif Los Angeles, CA 90095 USA.
    Zou, Yingping
    Cent S Univ, Peoples R China.
    Zhang, Huotian
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Yang, Jonathan Lee
    Univ Calif Berkeley, CA 94720 USA.
    Chang, Sheng-Yung
    Univ Calif Los Angeles, CA 90095 USA.
    Zhang, Zhenzhen
    Cent S Univ, Peoples R China.
    Huang, Wenchao
    Univ Calif Los Angeles, CA 90095 USA.
    Wang, Rui
    Univ Calif Los Angeles, CA 90095 USA.
    Meng, Dong
    Univ Calif Los Angeles, CA 90095 USA.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Yang, Yang
    Univ Calif Los Angeles, CA 90095 USA; Univ Calif Los Angeles, CA 90095 USA.
    Enabling low voltage losses and high photocurrent in fullerene-free organic photovoltaics2019Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, artikel-id 570Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Despite significant development recently, improving the power conversion efficiency of organic photovoltaics (OPVs) is still an ongoing challenge to overcome. One of the prerequisites to achieving this goal is to enable efficient charge separation and small voltage losses at the same time. In this work, a facile synthetic strategy is reported, where optoelectronic properties are delicately tuned by the introduction of electron-deficient-core-based fused structure into non-fullerene acceptors. Both devices exhibited a low voltage loss of 0.57 V and high short-circuit current density of 22.0 mA cm(-2), resulting in high power conversion efficiencies of over 13.4%. These unconventional electron-deficient-core-based non-fullerene acceptors with near-infrared absorption lead to low non-radiative recombination losses in the resulting organic photovoltaics, contributing to a certified high power conversion efficiency of 12.6%.

  • 19.
    Yuan, Jun
    et al.
    Univ Calif Los Angeles, CA 90095 USA; Cent S Univ, Peoples R China; Univ Calif Los Angeles, CA 90095 USA.
    Huang, Tianyi
    Univ Calif Los Angeles, CA 90095 USA.
    Cheng, Pei
    Univ Calif Los Angeles, CA 90095 USA.
    Zou, Yingping
    Cent S Univ, Peoples R China.
    Zhang, Huotian
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Yang, Jonathan Lee
    Univ Calif Berkeley, CA 94720 USA.
    Chang, Sheng-Yung
    Univ Calif Los Angeles, CA 90095 USA.
    Zhang, Zhenzhen
    Cent S Univ, Peoples R China.
    Huang, Wenchao
    Univ Calif Los Angeles, CA 90095 USA.
    Wang, Rui
    Univ Calif Los Angeles, CA 90095 USA.
    Meng, Dong
    Univ Calif Los Angeles, CA 90095 USA; Univ Calif Los Angeles, CA 90095 USA.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Yang, Yang
    Univ Calif Los Angeles, CA 90095 USA.
    Enabling low voltage losses and high photocurrent in fullerene-free organic photovoltaics (vol 10, 570, 2019)2019Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, artikel-id 1624Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    n/a

  • 20.
    Upreti, Tanvi
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Wang, Yuming
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Zhang, Huotian
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Scheunemann, Dorothea
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Kemerink, Martijn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Experimentally Validated Hopping-Transport Model for Energetically Disordered Organic Semiconductors2019Ingår i: Physical Review Applied, E-ISSN 2331-7019, Vol. 12, nr 6, artikel-id 064039Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Charge transport in disordered organic semiconductors occurs by hopping of charge carriers between localized sites that are randomly distributed in a strongly energy-dependent density of states. Extracting disorder and hopping parameters from experimental data, such as temperature-dependent current-voltage characteristics, typically relies on parametrized mobility functionals that are integrated in a drift-diffusion solver. Surprisingly, the functional based on the extended Gaussian disorder model (eGDM) is extremely successful at this, despite it being based on the assumption of nearest neighbor hopping (nnH) on a regular lattice. We here propose a variable-range hopping (VRH) model that is integrated in a freeware drift-diffusion solver. The mobility model is calibrated using kinetic Monte Carlo calculations and shows good agreement with the Monte Carlo calculations over the experimentally relevant part of the parameter space. The model is applied to temperature-dependent space-charge-limited current (SCLC) measurements of different systems. In contrast to the eGDM, the VRH model provides a consistent description of both p- and n-type devices. We find a critical ratio of a(NN)/alpha (mean intersite distance:localization radius) of about three, below which hopping to non-nearest neighbors becomes important around room temperature and the eGDM cannot be used for parameter extraction. Typical (Gaussian) disorder values in the range 45-120 meV are found, without any clear correlation with photovoltaic performance, when the same active layer is used in an organic solar cell.

  • 21.
    Qing, Jian
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Shenzhen Univ, Peoples R China.
    Kuang, Chaoyang
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Wang, Heyong
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Wang, Yuming
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Liu, Xiaoke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Bai, Sai
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Li, Mingjie
    Nanyang Technol Univ, Singapore.
    Sum, Tze Chien
    Nanyang Technol Univ, Singapore.
    Hu, Zhang-Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Zhang, Wenjing
    Shenzhen Univ, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    High-Quality Ruddlesden-Popper Perovskite Films Based on In Situ Formed Organic Spacer Cations2019Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, artikel-id 1904243Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ruddlesden-Popper perovskites (RPPs), consisting of alternating organic spacer layers and inorganic layers, have emerged as a promising alternative to 3D perovskites for both photovoltaic and light-emitting applications. The organic spacer layers provide a wide range of new possibilities to tune the properties and even provide new functionalities for RPPs. However, the preparation of state-of-the-art RPPs requires organic ammonium halides as the starting materials, which need to be ex situ synthesized. A novel approach to prepare high-quality RPP films through in situ formation of organic spacer cations from amines is presented. Compared with control devices fabricated from organic ammonium halides, this new approach results in similar (and even better) device performance for both solar cells and light-emitting diodes. High-quality RPP films are fabricated based on different types of amines, demonstrating the universality of the approach. This approach not only represents a new pathway to fabricate efficient devices based on RPPs, but also provides an effective method to screen new organic spacers with further improved performance.

    Publikationen är tillgänglig i fulltext från 2020-08-28 15:10
  • 22.
    Kumawat, Naresh Kumar
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Yuan, Zhongcheng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Bai, Sai
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Metal Doping/Alloying of Cesium Lead Halide Perovskite Nanocrystals and their Applications in Light-Emitting Diodes with Enhanced Efficiency and Stability2019Ingår i: Israel Journal of Chemistry, ISSN 0021-2148, Vol. 59, nr 8, s. 695-707Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Metal halide perovskite nanocrystals (NCs) have demonstrated great advances for light-emitting diodes (LEDs) applications, owing to their excellent optical, electrical properties and cost-effective solution-processing potentials. Tremendous progress has been made in perovskite NCs-based LEDs during the past several years, with the external quantum efficiency (EQE) boosted to over 20 %. Recently, metal doping/alloying strategy has been explored to finely tune the optoelectronic properties and enhance material stability of perovskite NCs, leading to further improved device efficiency and stability of the obtained perovskite NCs-based LEDs. In this review, we summarize recent progress on the metal doping/alloying of perovskite NCs and their applications in LEDs. We focus on the effects of different metal doping strategies on the structural and optoelectronic properties of the perovskite NCs. In addition, several works on high-performance LEDs based on metal doped/alloyed perovskite NCs with different light emission colours are highlighted. Finally, we present an outlook on employing metal doping/alloying strategies to further improve the device efficiency and stability of LEDs based on perovskite NCs.

    Publikationen är tillgänglig i fulltext från 2020-05-03 11:34
  • 23.
    Liu, Feng
    et al.
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Zhang, Jianyun
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Wang, Yuming
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Chen, Shanshan
    Ulsan Natl Inst Sci and Technol, South Korea.
    Zhou, Zichun
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Yang, Changduk
    Ulsan Natl Inst Sci and Technol, South Korea.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Zhu, Xiaozhang
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Modulating Structure Ordering via Side-Chain Engineering of Thieno[3,4-b]thiophene-Based Electron Acceptors for Efficient Organic Solar Cells with Reduced Energy Losses2019Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, nr 38, s. 35193-35200Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nonfullerene-based organic solar cells (OSCs) have made a huge breakthrough in the recent years. Introducing a proper side chain on the pi-conjugated backbone plays a vital role for further improving the power conversion efficiency (PCE) of OSCs due to easy tuning of the physical properties of the molecule such as absorption, energetic level, solid-state stacking, and charge transportation. More importantly, the side chain significantly affected the blend films morphology and thus determined the PCEs of the devices. In this work, two low-band-gap nonfullerene acceptors, ATT-4 and ATT-5, with an alkyl or branched alkyl substitute on indacenodithiophene (IDT) and thieno[3,4-b]thiophene (TbT) backbone were synthesized for investigating the effect of the substituent on the performance of the nonfullerene acceptors (NFAs). In comparison to ATT-1 with p-hexylphenyl-substituted IDT and n-octyl-substituted TbT moieties, ATT-4 and ATT-5 exhibit better crystallinity with shorter interchain distance and ordered molecular structure in neat and the corresponding blend films. The tailored ATT-5 exhibits a high PCE of 12.36% with a V-oc of 0.93 V, J(sc) of 18.86 mA cm(-2), and fill factor (FF) of 0.71, blending with a wide-band-gap polymer donor PBDB-T. Remarkably, although ATT-4 and ATT-5 exhibit broader light absorption, the devices obtained higher V-oc than that of ATT-1 mainly due to the reduced nonradiative recombination in the blend films. These results implied that side-chain engineering is an efficient approach to regulate the electronic structure and molecular packing of NFAs, which can well match with polymer donor, and obtain high PCEs of the OSCs with improved V-oc, J(sc), and FF, simultaneously.

  • 24.
    Cui, Yong
    et al.
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Yao, Huifeng
    Chinese Acad Sci, Peoples R China.
    Zhang, Jianqi
    Natl Ctr Nanosci and Technol, Peoples R China.
    Zhang, Tao
    Chinese Acad Sci, Peoples R China.
    Wang, Yuming
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Hong, Ling
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Xian, Kaihu
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Xu, Bowei
    Chinese Acad Sci, Peoples R China.
    Zhang, Shaoqing
    Chinese Acad Sci, Peoples R China; Univ Sci and Technol Beijing, Peoples R China.
    Peng, Jing
    Organtec Ltd, Peoples R China.
    Wei, Zhixiang
    Natl Ctr Nanosci and Technol, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Hou, Jianhui
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Over 16% efficiency organic photovoltaic cells enabled by a chlorinated acceptor with increased open-circuit voltages2019Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, artikel-id 2515Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Broadening the optical absorption of organic photovoltaic (OPV) materials by enhancing the intramolecular push-pull effect is a general and effective method to improve the power conversion efficiencies of OPV cells. However, in terms of the electron acceptors, the most common molecular design strategy of halogenation usually results in down-shifted molecular energy levels, thereby leading to decreased open-circuit voltages in the devices. Herein, we report a chlorinated non-fullerene acceptor, which exhibits an extended optical absorption and meanwhile displays a higher voltage than its fluorinated counterpart in the devices. This unexpected phenomenon can be ascribed to the reduced non-radiative energy loss (0.206 eV). Due to the simultaneously improved short-circuit current density and open-circuit voltage, a high efficiency of 16.5% is achieved. This study demonstrates that finely tuning the OPV materials to reduce the bandgap-voltage offset has great potential for boosting the efficiency.

  • 25.
    Bai, Sai
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Univ Oxford, England.
    Da, Peimei
    Univ Oxford, England.
    Li, Cheng
    Univ Bayreuth, Germany; Xiamen Univ, Peoples R China.
    Wang, Zhiping
    Univ Oxford, England.
    Yuan, Zhongcheng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Fu, Fan
    Empa-Swiss Federal Laboratories for Materials Science and Technology, Duebendorf, Switzerland.
    Kawecki, Maciej
    Empa, Switzerland; Univ Basel, Switzerland.
    Liu, Xianjie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Sakai, Nobuya
    Univ Oxford, England.
    Wang, Jacob Tse-Wei
    CSIRO Energy, Australia.
    Huettner, Sven
    Univ Bayreuth, Germany.
    Buecheler, Stephan
    Empa Swiss Fed Labs Mat Sci and Technol, Switzerland.
    Fahlman, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Univ Oxford, England.
    Snaith, Henry J.
    Univ Oxford, England.
    Planar perovskite solar cells with long-term stability using ionic liquid additives2019Ingår i: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 571, nr 7764, s. 245-250Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Solar cells based on metal halide perovskites are one of the most promising photovoltaic technologies(1-4). Over the past few years, the long-term operational stability of such devices has been greatly improved by tuning the composition of the perovskites(5-9), optimizing the interfaces within the device structures(10-13), and using new encapsulation techniques(14,15). However, further improvements are required in order to deliver a longer-lasting technology. Ion migration in the perovskite active layer-especially under illumination and heat-is arguably the most difficult aspect to mitigate(16-18). Here we incorporate ionic liquids into the perovskite film and thence into positive-intrinsic-negative photovoltaic devices, increasing the device efficiency and markedly improving the long-term device stability. Specifically, we observe a degradation in performance of only around five per cent for the most stable encapsulated device under continuous simulated full-spectrum sunlight for more than 1,800 hours at 70 to 75 degrees Celsius, and estimate that the time required for the device to drop to eighty per cent of its peak performance is about 5,200 hours. Our demonstration of long-term operational, stable solar cells under intense conditions is a key step towards a reliable perovskite photovoltaic technology.

  • 26.
    Ponseca, Carlito
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Arlauskas, Andrius
    Ctr Phys Sci and Technol, Lithuania.
    Yu, Hongling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Wang, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Nevinskas, Ignas
    Ctr Phys Sci and Technol, Lithuania.
    Duda, Eimantas
    Ctr Phys Sci and Technol, Lithuania.
    Vaicaitis, Virgilijus
    Vilnius Univ, Lithuania.
    Eriksson, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensor- och aktuatorsystem. Linköpings universitet, Tekniska fakulteten.
    Bergqvist, Jonas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Liu, Xiaoke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Kemerink, Martijn
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Komplexa material och system. Linköpings universitet, Tekniska fakulteten.
    Krotkus, Arunas
    Ctr Phys Sci and Technol, Lithuania.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Pulsed Terahertz Emission from Solution-Processed Lead Iodide Perovskite Films2019Ingår i: ACS Photonics, E-ISSN 2330-4022, Vol. 6, nr 5, s. 1175-1181Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We report pulsed terahertz (THz) emission from solution-processed metal halide perovskite films with electric field 1 order of magnitude lower than p-InAs, an efficient THz emitter. Such emission is enabled by a unique combination of efficient charge separation, high carrier mobilities, and more importantly surface defects. The mechanism of generation was identified by investigating the dependence of the THz electric field amplitude on surface defect densities, excess charge carriers, excitation intensity and energy, temperature, and external electric field. We also show for the first time THz emission from a curved surface, which is not possible for any crystalline semiconductor and paves the way to focus high-intensity sources. These results represent a possible new direction for perovskite optoelectronics and for THz emission spectroscopy as a complementary tool in investigating surface defects on metal halide perovskites, of fundamental importance in the optimization of solar cells and light-emitting diodes.

  • 27.
    Xu, Weidong
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech), Nanjing, China.
    Hu, Qi
    Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech), Nanjing, China.
    Bai, Sai
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Bao, Chunxiong
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology, Shenzhen University, Shenzhen, China.
    Miao, Yanfeng
    Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech), Nanjing, China.
    Yuan, Zhongcheng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Borzda, Tetiana
    Center for Nano Science and Technology @Polimi, Istituto Italiano di Tecnologia, Milan, Italy.
    Barker, Alex J.
    Center for Nano Science and Technology @Polimi, Istituto Italiano di Tecnologia, Milan, Italy.
    Tyukalova, Elizaveta
    School of Materials Science and Engineering, Nanyang Technological University (NTU), Singapore, Singapore.
    Hu, Zhang-Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Kawecki, Maciej
    Laboratory for Nanoscale Materials Science, Empa, Dubendorf, Switzerland / Department of Physics, University of Basel, Basel, Switzerland.
    Wang, Heyong
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Yan, Zhibo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Laboratory of Solid State Microstructures and Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, P. R. China.
    Liu, Xianjie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Shi, Xiaobo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Uvdal, Kajsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Fahlman, Mats
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Zhang, Wenjing
    International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology, Shenzhen University, Shenzhen, China.
    Duchamp, Martial
    School of Materials Science and Engineering, Nanyang Technological University (NTU), Singapore, Singapore.
    Liu, Jun-Ming
    Laboratory of Solid State Microstructures and Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, P. R. China.
    Petrozza, Annamaria
    Center for Nano Science and Technology @Polimi, Istituto Italiano di Tecnologia, Milan, Italy.
    Wang, Jianpu
    Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech), Nanjing, China.
    Liu, Li-Min
    Beijing Computational Science Research Center, Beijing, China / chool of Physics, Beihang University, Beijing, China .
    Huang, Wei
    ey Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University (NanjingTech), Nanjing, China / Shaanxi Institute of Flexible Electronics (SIFE), Northwestern Polytechnical University (NPU), Xi’an, China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Rational molecular passivation for high-performance perovskite light-emitting diodes2019Ingår i: Nature Photonics, ISSN 1749-4885, E-ISSN 1749-4893, Vol. 13, nr 6, s. 418-424Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A major efficiency limit for solution-processed perovskite optoelectronic devices, for example light-emitting diodes, is trap-mediated non-radiative losses. Defect passivation using organic molecules has been identified as an attractive approach to tackle this issue. However, implementation of this approach has been hindered by a lack of deep understanding of how the molecular structures influence the effectiveness of passivation. We show that the so far largely ignored hydrogen bonds play a critical role in affecting the passivation. By weakening the hydrogen bonding between the passivating functional moieties and the organic cation featuring in the perovskite, we significantly enhance the interaction with defect sites and minimize non-radiative recombination losses. Consequently, we achieve exceptionally high-performance near-infrared perovskite light-emitting diodes with a record external quantum efficiency of 21.6%. In addition, our passivated perovskite light-emitting diodes maintain a high external quantum efficiency of 20.1% and a wall-plug efficiency of 11.0% at a high current density of 200 mA cm−2, making them more attractive than the most efficient organic and quantum-dot light-emitting diodes at high excitations.

    Publikationen är tillgänglig i fulltext från 2020-03-25 16:05
  • 28.
    Cheng, Hao-Wen
    et al.
    Univ Calif Los Angeles, CA 90095 USA; Natl Chiao Tung Univ, Taiwan.
    Zhang, Huotian
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Lin, Yu-Che
    Univ Calif Los Angeles, CA 90095 USA; Natl Chiao Tung Univ, Taiwan.
    She, Nian-Zu
    Natl Chiao Tung Univ, Taiwan.
    Wang, Rui
    Univ Calif Los Angeles, CA 90095 USA.
    Chen, Chung-Hao
    Natl Chiao Tung Univ, Taiwan.
    Yuan, Jun
    Univ Calif Los Angeles, CA 90095 USA; Cent S Univ, Peoples R China.
    Tsao, Cheng-Si
    Natl Taiwan Univ, Taiwan; Inst Nucl Energy Res, Taiwan.
    Yabushita, Atsushi
    Natl Chiao Tung Univ, Taiwan.
    Zou, Yingping
    Cent S Univ, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Cheng, Pei
    Univ Calif Los Angeles, CA 90095 USA.
    Wei, Kung-Hwa
    Natl Chiao Tung Univ, Taiwan.
    Yang, Yang
    Univ Calif Los Angeles, CA 90095 USA.
    Realizing Efficient Charge/Energy Transfer and Charge Extraction in Fullerene-Free Organic Photovoltaics via a Versatile Third Component2019Ingår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 19, nr 8, s. 5053-5061Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Solution-processed organic photovoltaics (OPVs) based on bulk-heterojunctions have gained significant attention to alleviate the increasing demend of fossil fuel in the past two decades. OPVs combined of a wide bandgap polymer donor and a narrow bandgap nonfullerene acceptor show potential to achieve high performance. However, there are still two reasons to limit the OPVs performance. One, although this combination can expand from the ultraviolet to the near-infrared region, the overall external quantum efficiency of the device suffers low values. The other one is the low open-circuit voltage (V-OC) of devices resulting from the relatively downshifted lowest unoccupied molecular orbital (LUMO) of the narrow bandgap. Herein, the approach to select and incorporate a versatile third component into the active layer is reported. A third component with a bandgap larger than that of the acceptor, and absorption spectra and LUMO levels lying within that of the donor and acceptor, is demonstrated to be effective to conquer these issues. As a result, the power conversion efficiencies (PCEs) are enhanced by the elevated short-circuit current and V-OC; the champion PCEs are 11.1% and 13.1% for PTB7-Th:IEICO-4F based and PBDB-T:Y1 based solar cells, respectively.

  • 29.
    Kniepert, Juliane
    et al.
    Univ Potsdam, Germany.
    Paulke, Andreas
    Univ Potsdam, Germany.
    Perdigon-Toro, Lorena
    Univ Potsdam, Germany.
    Kurpiers, Jona
    Univ Potsdam, Germany.
    Zhang, Huotian
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Yuan, Jun
    Cent S Univ, Peoples R China.
    Zou, Yingping
    Cent S Univ, Peoples R China.
    Le Corre, Vincent M.
    Zernike Inst Adv Mat, Netherlands.
    Koster, L. Jan Anton
    Zernike Inst Adv Mat, Netherlands.
    Neher, Dieter
    Univ Potsdam, Germany.
    Reliability of charge carrier recombination data determined with charge extraction methods2019Ingår i: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 126, nr 20, artikel-id 205501Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Charge extraction methods are popular for measuring the charge carrier density in thin film organic solar cells and to draw conclusions about the order and coefficient of nongeminate charge recombination. However, results from such studies may be falsified by inhomogeneous steady state carrier profiles or surface recombination. Here, we present a detailed drift-diffusion study of two charge extraction methods, bias-assisted charge extraction (BACE) and time-delayed collection field (TDCF). Simulations are performed over a wide range of the relevant parameters. Our simulations reveal that both charge extraction methods provide reliable information about the recombination order and coefficient if the measurements are performed under appropriate conditions. However, results from BACE measurements may be easily affected by surface recombination, in particular for small active layer thicknesses and low illumination densities. TDCF, on the other hand, is more robust against surface recombination due to its transient nature but also because it allows for a homogeneous high carrier density to be inserted into the active layer. Therefore, TDCF is capable to provide meaningful information on the order and coefficient of recombination even if the model conditions are not exactly fulfilled. We demonstrate this for an only 100 nm thick layer of a highly efficient nonfullerene acceptor (NFA) blend, comprising the donor polymer PM6 and the NFA Y6. TDCF measurements were performed as a function of delay time for different laser fluences and bias conditions. The full set of data could be consistently fitted by a strict second order recombination process, with a bias- and fluence-independent bimolecular recombination coefficient k(2) = 1.7 x 10(-17)m(3) s(-1). BACE measurements performed on the very same layer yielded the identical result, despite the very different excitation conditions. This proves that recombination in this blend is mostly through processes in the bulk and that surface recombination is of minor importance despite the small active layer thickness. Published under license by AIP Publishing.

  • 30.
    Zou, Yatao
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Soochow Univ, Peoples R China.
    Xu, Hao
    Soochow Univ, Peoples R China.
    Li, Siying
    Soochow Univ, Peoples R China.
    Song, Tao
    Soochow Univ, Peoples R China.
    Kuai, Liang
    Soochow Univ, Peoples R China.
    Bai, Sai
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Sun, Baoquan
    Soochow Univ, Peoples R China.
    Spectral-Stable Blue Emission from Moisture-Treated Low-Dimensional Lead Bromide-Based Perovskite Films2019Ingår i: ACS Photonics, E-ISSN 2330-4022, Vol. 6, nr 7, s. 1728-1735Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Highly efficient light-emitting diodes (LEDs) based on metal halide perovskites with green, red, and near-infrared electro-luminescence have been widely demonstrated. However, the development of their blue counterparts is still hampered due to the difficult deposition of efficient and spectral-stable blue-emitting active layers. Here, we report a facile and general approach that uses a moisture treatment in combination with the precursor stoichiometry engineering for the fabrication of efficient and color stable blue-emitting perovskite films. We find that, with a short-term moisture exposure, light emission from Ruddlesden Popper lead bromide-based perovskite films exhibit a continuous blue-shift from 512 to 475 nm through incorporating excess CsBr in the precursors. In addition, we observe that the formed Cs4PbBr6 phase under CsBr-rich condition is favorable to stabilize the blue emission of the resulting films. The corresponding blue-emitting perovskite films exhibit a photoluminescence quantum efficiency of over 20%, delivering sky-blue perovskite LEDs with no change in the light emission even under high voltage. Our strategy provides an alternative way for realizing efficient and spectrally stable active layers for the further development of blue-emitting perovskite LEDs.

  • 31.
    Miao, Yanfeng
    et al.
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Ke, You
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Wang, Nana
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Zou, Wei
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Xu, Mengmeng
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Cao, Yu
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Sun, Yan
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Yang, Rong
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Wang, Ying
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Tong, Yunfang
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Xu, Wenjie
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Zhang, Liangdong
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Li, Renzhi
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Li, Jing
    Zhejiang Univ, Peoples R China.
    He, Haiping
    Zhejiang Univ, Peoples R China.
    Jin, Yizheng
    Zhejiang Univ, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Huang, Wei
    Nanjing Tech Univ NanjingTech, Peoples R China; Nanjing Univ Posts and Telecommun, Peoples R China; Nanjing Univ Posts and Telecommun, Peoples R China; Northwestern Polytech Univ, Peoples R China.
    Wang, Jianpu
    Nanjing Tech Univ NanjingTech, Peoples R China.
    Stable and bright formamidinium-based perovskite light-emitting diodes with high energy conversion efficiency2019Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, artikel-id 3624Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Solution-processable perovskites show highly emissive and good charge transport, making them attractive for low-cost light-emitting diodes (LEDs) with high energy conversion efficiencies. Despite recent advances in device efficiency, the stability of perovskite LEDs is still a major obstacle. Here, we demonstrate stable and bright perovskite LEDs with high energy conversion efficiencies by optimizing formamidinium lead iodide films. Our LEDs show an energy conversion efficiency of 10.7%, and an external quantum efficiency of 14.2% without outcoupling enhancement through controlling the concentration of the precursor solutions. The device shows low efficiency droop, i.e. 8.3% energy conversion efficiency and 14.0% external quantum efficiency at a current density of 300 mA cm(-2), making the device more efficient than state-of-the-art organic and quantum-dot LEDs at high current densities. Furthermore, the half-lifetime of device with benzylamine treatment is 23.7 hr under a current density of 100 mA cm(-2), comparable to the lifetime of near-infrared organic LEDs.

  • 32.
    Yang, Jie
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Shenzhen Univ, Peoples R China.
    Bao, Chunxiong
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Shenzhen Univ, Peoples R China.
    Ning, Weihua
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Nanjing Tech Univ, Peoples R China.
    Wu, Bo
    Nanyang Technol Univ, Singapore.
    Ji, Fuxiang
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Yan, Zhibo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Nanjing Univ, Peoples R China.
    Tao, Youtian
    Nanjing Tech Univ, Peoples R China.
    Liu, Jun-Ming
    Nanjing Univ, Peoples R China.
    Sum, Tze Chien
    Nanyang Technol Univ, Singapore.
    Bai, Sai
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Wang, Jianpu
    Nanjing Tech Univ, Peoples R China.
    Huang, Wei
    Nanjing Tech Univ, Peoples R China.
    Zhang, Wenjing
    Shenzhen Univ, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Stable, High-Sensitivity and Fast-Response Photodetectors Based on Lead-Free Cs2AgBiBr6 Double Perovskite Films2019Ingår i: Advanced Optical Materials, ISSN 2162-7568, E-ISSN 2195-1071, Vol. 7, nr 13, artikel-id 1801732Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Solution-processed metal halide perovskites (MHPs) have demonstrated great advances on achieving high-performance photodetectors. However, the intrinsic material instability and the toxicity of lead still hinder the practical applications of MHPs-based photodetectors. In this work, the first highly sensitive and fast-response lead-free perovskite photodetectors based on Cs2AgBiBr6 double perovskite films are demonstrated. A convenient solution method is developed to deposit high-quality Cs2AgBiBr6 film with large grain sizes, low trap densities, and long charge carrier lifetimes. Incorporated within a photodiode device architecture comprised of optimized hole- and electron-transporting layers, lead-free perovskite photodetectors are achieved exhibiting a high detectivity of 3.29 x 10(12) Jones, a large linear dynamic range of 193 dB, and a fast response time of approximate to 17 ns. All the key figures of merit of the devices are comparable with the reported best-performing photodetectors based on lead halide perovskites. In addition, the resulting devices exhibit excellent thermal and environmental stability. The nonencapsulated devices show negligible degradation after thermal stressing at 150 degrees C and less than 5% degradation in the photoresponsivity after storage in ambient air for approximate to 2300 h. The results demonstrate the great potential of the lead-free Cs2AgBiBr6 double perovskite in applications for environmentally friendly and high-performance photodetectors.

  • 33.
    Ning, Weihua
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Nanjing Tech Univ, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Structural and Functional Diversity in Lead-Free Halide Perovskite Materials2019Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 31, nr 22, artikel-id 1900326Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lead halide perovskites have emerged as promising semiconducting materials for different applications owing to their superior optoelectronic properties. Although the community holds different views toward the toxic lead in these high-performance perovskites, it is certainly preferred to replace lead with nontoxic, or at least less-toxic, elements while maintaining the superior properties. Here, the design rules for lead-free perovskite materials with structural dimensions from 3D to 0D are presented. Recent progress in lead-free halide perovskites is reviewed, and the relationships between the structures and fundamental properties are summarized, including optical, electric, and magnetic-related properties. 3D perovskites, especially A(2)B(+)B(3+)X(6)-type double perovskites, demonstrate very promising optoelectronic prospects, while low-dimensional perovskites show rich structural diversity, resulting in abundant properties for optical, electric, magnetic, and multifunctional applications. Furthermore, based on these structure-property relationships, strategies for multifunctional perovskite design are proposed. The challenges and future directions of lead-free perovskite applications are also highlighted, with emphasis on materials development and device fabrication. The research on lead-free halide perovskites at Linkoping University has benefited from inspirational discussions with Prof. Olle Inganas.

    Publikationen är tillgänglig i fulltext från 2020-04-26 14:04
  • 34.
    Yang, Lei
    et al.
    Univ Chinese Acad Sci, Peoples R China; Imperial Coll London, England.
    Qin, Linqing
    Univ Chinese Acad Sci, Peoples R China.
    Xu, Yunxiao
    Univ Chinese Acad Sci, Peoples R China.
    Zhang, Huotian
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Lv, Lei
    Univ Chinese Acad Sci, Peoples R China.
    Chen, Kepeng
    Dalian Univ Technol, Peoples R China.
    Sui, Xinyu
    Natl Ctr Nanosci and Technol, Peoples R China.
    Zhong, Yangguang
    Natl Ctr Nanosci and Technol, Peoples R China.
    Guo, Yuan
    Chinese Acad Sci, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Zhao, Jianzhang
    Dalian Univ Technol, Peoples R China.
    Li, Yuhao
    Chinese Univ Hong Kong, Peoples R China.
    Liu, Xinfeng
    Natl Ctr Nanosci and Technol, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Yi, Yuanping
    Chinese Acad Sci, Peoples R China.
    Lu, Xinhui
    Chinese Univ Hong Kong, Peoples R China.
    Peng, Aidong
    Univ Chinese Acad Sci, Peoples R China.
    Huang, Hui
    Univ Chinese Acad Sci, Peoples R China.
    Sulfur vs. tellurium: the heteroatom effects on the nonfullerene acceptors2019Ingår i: Science in China Series B: Chemistry, ISSN 1674-7291, E-ISSN 1869-1870, Vol. 62, nr 7, s. 897-903Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of chalcogen heteroatom variation on donor materials has been systematically investigated. However, this effect on acceptors has rarely been explored. Herein, nonfullerene acceptors BFPSP and BFPTP were reported by simply changing the chalcogen atoms from S to Te. The differences between BFPSP and BFPTP in light absorption, energy levels, excited-state lifetimes, energy loss, charge mobilities, morphology, and photovoltaic properties were systematically investigated to understand the heteroatom effects. More importantly, the electroluminescence spectra, external quantum efficiency of photovoltaics and TD-DFT calculations revealed that the triplet excited state (T-1) in energy of BFPTP equals to the charge transfer (CT) state in PBDB-T:BFPTP, which allows T-1 excitons, generated by intersystem crossing, to split into free charges to contribute to the efficiency. This contribution provides a strategy for tuning the photophysical properties of nonfullerene acceptors and designing high performance triplet materials for OSCs.

  • 35.
    Rech, Jeromy J.
    et al.
    Univ N Carolina, NC 27599 USA.
    Bauer, Nicole
    Univ N Carolina, NC 27599 USA.
    Dirkes, David
    Univ N Carolina, NC 27599 USA.
    Kaplan, Joseph
    Univ N Carolina, NC 27599 USA.
    Peng, Zhengxing
    North Carolina State Univ, NC 27695 USA.
    Zhang, Huotian
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Ye, Long
    North Carolina State Univ, NC 27695 USA.
    Liu, Shubin
    Univ N Carolina, NC 27599 USA.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Ade, Harald
    North Carolina State Univ, NC 27695 USA.
    You, Wei
    Univ N Carolina, NC 27599 USA.
    The crucial role of end group planarity for fused-ring electron acceptors in organic solar cells2019Ingår i: MATERIALS CHEMISTRY FRONTIERS, ISSN 2052-1537, Vol. 3, nr 8, s. 1642-1652Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Newly developed fused-ring electron acceptors (FREAs) have proven to be an effective class of materials for extending the absorption window and boosting the efficiency of organic photovoltaics (OPVs). While numerous acceptors have been developed, there is surprisingly little structural diversity among high performance FREAs in literature. Of the high efficiency electron acceptors reported, the vast majority utilize derivatives of 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile (INCN) as the acceptor moiety. It has been postulated that the high electron mobility exhibited by FREA molecules with INCN end groups is a result of close pi-pi stacking between the neighboring planar INCN groups, forming an effective charge transport pathway between molecules. To explore this as a design rationale for electron acceptors, we synthesized a new fused-ring electron acceptor, IDTCF, which has methyl substituents out of plane to the conjugated acceptor backbone. These methyl groups hinder packing and expand the pi-pi stacking distance by similar to 1 angstrom, but have little impact on the optical or electrochemical properties of the individual FREA molecule. The extra steric hindrance from the out of plane methyl substituents restricts packing and results in large amounts of geminate recombination, thus degrading the device performance. Our results show that intermolecular interactions (especially pi-pi stacking between end groups) play a crucial role in performance of FREAs. We demonstrated that the planarity of the acceptor unit is of paramount importance as even minor deviations in end group distance are enough to disrupt crystallinity and cripple device performance.

  • 36.
    Ning, Weihua
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Nanjing Tech Univ, Peoples R China.
    Zhao, Xin-Gang
    Jilin Univ, Peoples R China.
    Klarbring, Johan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Bai, Sai
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Ji, Fuxiang
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Wang, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Simak, Sergey
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Tao, Youtian
    Nanjing Tech Univ, Peoples R China.
    Ren, Xiao-Ming
    Nanjing Tech Univ, Peoples R China.
    Zhang, Lijun
    Jilin Univ, Peoples R China.
    Huang, Wei
    Nanjing Tech Univ, Peoples R China.
    Abrikosov, Igor
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten. Natl Univ Sci and Technol MISIS, Russia.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Thermochromic Lead-Free Halide Double Perovskites2019Ingår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 29, nr 10, artikel-id 1807375Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lead-free halide double perovskites with diverse electronic structures and optical responses, as well as superior material stability show great promise for a range of optoelectronic applications. However, their large bandgaps limit their applications in the visible light range such as solar cells. In this work, an efficient temperature-derived bandgap modulation, that is, an exotic fully reversible thermochromism in both single crystals and thin films of Cs2AgBiBr6 double perovskites is demonstrated. Along with the thermochromism, temperature-dependent changes in the bond lengths of Ag Symbol of the Klingon Empire Br (R-Ag Symbol of the Klingon Empire Br) and Bi Symbol of the Klingon Empire Br (R-Bi Symbol of the Klingon Empire Br) are observed. The first-principle molecular dynamics simulations reveal substantial anharmonic fluctuations of the R-Ag Symbol of the Klingon Empire Br and R-Bi Symbol of the Klingon Empire Br at high temperatures. The synergy of anharmonic fluctuations and associated electron-phonon coupling, and the peculiar spin-orbit coupling effect, is responsible for the thermochromism. In addition, the intrinsic bandgap of Cs2AgBiBr6 shows negligible changes after repeated heating/cooling cycles under ambient conditions, indicating excellent thermal and environmental stability. This work demonstrates a stable thermochromic lead-free double perovskite that has great potential in the applications of smart windows and temperature sensors. Moreover, the findings on the structure modulation-induced bandgap narrowing of Cs2AgBiBr6 provide new insights for the further development of optoelectronic devices based on the lead-free halide double perovskites.

  • 37.
    Giovanni, David
    et al.
    Nanyang Technol Univ, Singapore; Energy Res Inst NTU ERI N, Singapore.
    Lim, Jia Wei Melvin
    Nanyang Technol Univ, Singapore.
    Yuan, Zhongcheng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Lim, Swee Sien
    Nanyang Technol Univ, Singapore.
    Righetto, Marcello
    Nanyang Technol Univ, Singapore.
    Qing, Jian
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Zhang, Qiannan
    Nanyang Technol Univ, Singapore.
    Dewi, Herlina Arianita
    Energy Res Inst NTU ERI N, Singapore.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Mhaisalkar, Subodh Gautam
    Energy Res Inst NTU ERI N, Singapore; Nanyang Technol Univ, Singapore.
    Mathews, Nripan
    Energy Res Inst NTU ERI N, Singapore; Nanyang Technol Univ, Singapore.
    Sum, Tze Chien
    Nanyang Technol Univ, Singapore.
    Ultrafast long-range spin-funneling in solution-processed Ruddlesden-Popper halide perovskites2019Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, artikel-id 3456Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Room-temperature spin-based electronics is the vision of spintronics. Presently, there are few suitable material systems. Herein, we reveal that solution-processed mixed-phase Ruddlesden-Popper perovskite thin-films transcend the challenges of phonon momentum-scattering that limits spin-transfer in conventional semiconductors. This highly disordered system exhibits a remarkable efficient ultrafast funneling of photoexcited spin-polarized excitons from two-dimensional (2D) to three-dimensional (3D) phases at room temperature. We attribute this efficient exciton relaxation pathway towards the lower energy states to originate from the energy transfer mediated by intermediate states. This process bypasses the omnipresent phonon momentum-scattering in typical semiconductors with stringent band dispersion, which causes the loss of spin information during thermalization. Film engineering using graded 2D/3D perovskites allows unidirectional out-of-plane spin-funneling over a thickness of similar to 600 nm. Our findings reveal an intriguing family of solution-processed perovskites with extraordinary spin-preserving energy transport properties that could reinvigorate the concepts of spin-information transfer.

  • 38.
    Yuan, Zhongcheng
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Miao, Yanfeng
    Nanjing Tech Univ, Peoples R China.
    Hu, Zhang-Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Xu, Weidong
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Nanjing Tech Univ, Peoples R China.
    Kuang, Chaoyang
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Pan, Kang
    Nanjing Tech Univ, Peoples R China.
    Liu, Pinlei
    Nanjing Tech Univ, Peoples R China.
    Lai, Jingya
    Nanjing Tech Univ, Peoples R China.
    Sun, Baoquan
    Soochow Univ, Peoples R China.
    Wang, Jianpu
    Nanjing Tech Univ, Peoples R China.
    Bai, Sai
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Unveiling the synergistic effect of precursor stoichiometry and interfacial reactions for perovskite light-emitting diodes2019Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, artikel-id 2818Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Metal halide perovskites are emerging as promising semiconductors for cost-effective and high-performance light-emitting diodes (LEDs). Previous investigations have focused on the optimisation of the emissive perovskite layer, for example, through quantum confinement to enhance the radiative recombination or through defect passivation to decrease non-radiative recombination. However, an in-depth understanding of how the buried charge transport layers affect the perovskite crystallisation, though of critical importance, is currently missing for perovskite LEDs. Here, we reveal synergistic effect of precursor stoichiometry and interfacial reactions for perovskite LEDs, and establish useful guidelines for rational device optimization. We reveal that efficient deprotonation of the undesirable organic cations by a metal oxide interlayer with a high isoelectric point is critical to promote the transition of intermediate phases to highly emissive perovskite films. Combining our findings with effective defect passivation of the active layer, we achieve high-efficiency perovskite LEDs with a maximum external quantum efficiency of 19.6%.

  • 39.
    Cui, Yong
    et al.
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Wang, Yuming
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Bergqvist, Jonas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Yao, Huifeng
    Chinese Acad Sci, Peoples R China.
    Xu, Ye
    Univ Chinese Acad Sci, Peoples R China.
    Gao, Bowei
    Univ Chinese Acad Sci, Peoples R China.
    Yang, Chenyi
    Univ Sci and Technol Beijing, Peoples R China.
    Zhang, Shaoqing
    Univ Sci and Technol Beijing, Peoples R China.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Hou, Jianhui
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China; Univ Sci and Technol Beijing, Peoples R China.
    Wide-gap non-fullerene acceptor enabling high-performance organic photovoltaic cells for indoor applications2019Ingår i: NATURE ENERGY, ISSN 2058-7546, Vol. 4, nr 9, s. 768-775Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Organic photovoltaic cells are potential candidates to drive low power consumption off-grid electronics for indoor applications. However, their power conversion efficiency is still limited by relatively large losses in the open-circuit voltage and a non-optimal absorption spectrum for indoor illumination. Here, we carefully designed a non-fullerene acceptor named IO-4CI and blend it with a polymer donor named PBDB-TF to obtain a photoactive layer whose absorption spectrum matches that of indoor light sources. The photovoltaic characterizations reveal a low energy loss below 0.60 eV. As a result, the organic photovoltaic cell (1 cm(2)) shows a power conversion efficiency of 26.1% with an open-circuit voltage of 1.10 V under a light-emitting diode illumination of 1,000 lux (2,700 K). We also fabricated a large-area cell (4 cm(2)) through the blade-coating method. Our cell shows an excellent stability, maintaining its initial photovoltaic performance under continuous illumination of the indoor light source for 1,000 hours.

  • 40.
    Yang, Daobin
    et al.
    Yamagata Univ, Japan; Yamagata Univ, Japan.
    Wang, Yuming
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Sano, Takeshi
    Yamagata Univ, Japan; Yamagata Univ, Japan; Yamagata Univ, Japan.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Sasabe, Hisahiro
    Yamagata Univ, Japan; Yamagata Univ, Japan; Yamagata Univ, Japan.
    Kido, Junji
    Yamagata Univ, Japan; Yamagata Univ, Japan; Yamagata Univ, Japan.
    A minimal non- radiative recombination loss for efficient non- fullerene all- small- molecule organic solar cells with a low energy loss of 0.54 eV and high open- circuit voltage of 1.15 V+2018Ingår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, nr 28, s. 13918-13924Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Organic solar cells (OSCs) are considered as a promising next-generation photovoltaic technology because of their light weight, flexibility, and the potential of roll-to-roll fabrication. However, the relatively large energy loss (E-loss) from the optical bandgap (E-g) of the absorber to the open-circuit voltage (V-oc) of the device hinders further improvement of the PCEs of OSCs. Here, we report efficient non-fullerene all-small-molecule organic solar cells (NF all-SMOSCs), using DR3TBDTT and O-IDTBR as the donor and acceptor, respectively. We obtain a high electroluminescence yield (EQE(EL)) value of up to approximate to 4 x 10(-4) corresponding to a 0.21 eV non-radiative recombination loss, which is the smallest value for bulk-heterojunction (BHJ) OSCs so far. As a result, a low E-loss of 0.54 eV and a considerably high V-oc of 1.15 V are obtained for BHJ NF all-SMOSCs.

  • 41.
    Zhan, Lingling
    et al.
    Zhejiang Univ, Peoples R China.
    Li, Shuixing
    Zhejiang Univ, Peoples R China.
    Zhang, Huotian
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Lau, Tsz-Ki
    Chinese Univ Hong Kong, Peoples R China.
    Lu, Xinhui
    Chinese Univ Hong Kong, Peoples R China.
    Sun, Danyang
    Zhejiang Univ, Peoples R China.
    Wang, Peng
    Zhejiang Univ, Peoples R China.
    Shi, Minmin
    Zhejiang Univ, Peoples R China.
    Li, Chang-Zhi
    Zhejiang Univ, Peoples R China.
    Chen, Hongzheng
    Zhejiang Univ, Peoples R China.
    A Near-Infrared Photoactive Morphology Modifier Leads to Significant Current Improvement and Energy Loss Mitigation for Ternary Organic Solar Cells2018Ingår i: ADVANCED SCIENCE, ISSN 2198-3844, Vol. 5, nr 8, artikel-id 1800755Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Herein, efficient organic solar cells (OSCs) are realized with the ternary blend of a medium band gap donor (poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b]dithiophene))-alt-(5,5-(1,3-di-2-thienyl-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c]dithiophene-4,8-dione)] (PBDB-T)) with a low band gap acceptor (2,2-((2Z,2Z)-(((2,5-difluoro-1,4-phenylene)bis(4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b]dithiophene-6,2-diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (HF-PCIC)) and a near-infrared acceptor (2,2-((2Z,2Z)-(((4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-s-indaceno[1,2-b:5,6-b]dithiophene-2,7-diyl)bis(4-((2-ethylhexyl)oxy)thiophene-5,2-diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (IEICO-4F)). It is shown that the introduction of IEICO-4F third component into PBDB-T:HF-PCIC blend increases the short-circuit current density (J(sc)) of the ternary OSC to 23.46 mA cm(-2), with a 44% increment over those of binary devices. The significant current improvement originates from the broadened absorption range and the active layer morphology optimization through the introduction of IEICO-4F component. Furthermore, the energy loss of the ternary cells (0.59 eV) is much decreased over that of the binary cells (0.80 eV) due to the reduction of both radiative recombination from the absorption below the band gap and nonradiative recombination upon the addition of IEICO-4F. Therefore, the power conversion efficiency increases dramatically from 8.82% for the binary cells to 11.20% for the ternary cells. This work provides good examples for simultaneously achieving both significant current enhancement and energy loss mitigation in OSCs, which would lead to the further construction of highly efficient ternary OSCs.

  • 42.
    Qing, Jian
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. City Univ Hong Kong, Peoples R China.
    Liu, Xiaoke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Li, Mingjie
    Nanyang Technol Univ, Singapore.
    Liu, Feng
    Shanghai Jiao Tong University, Peoples Republic of China.
    Yuan, Zhongcheng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Tiukalova, Elizaveta
    Nanyang Technol Univ, Singapore.
    Yan, Zhibo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Nanjing Univ, Peoples R China.
    Duchamp, Martial
    Nanyang Technol Univ, Singapore.
    Chen, Shi
    Nanyang Technol Univ, Singapore; ASTAR, Singapore.
    Wang, Yuming
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Bai, Sai
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Univ Oxford, England.
    Liu, Jun-Ming
    Nanjing Univ, Peoples R China.
    Snaith, Henry J.
    Univ Oxford, England.
    Lee, Chun-Sing
    City Univ Hong Kong, Peoples R China.
    Sum, Tze Chien
    Nanyang Technol Univ, Singapore.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Shanghai Jiao Tong Univ, Peoples R China; Univ Oxford, England.
    Aligned and Graded Type-II Ruddlesden-Popper Perovskite Films for Efficient Solar Cells2018Ingår i: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 8, nr 21, artikel-id 1800185Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recently, Ruddlesden-Popper perovskites (RPPs) have attracted increasing interests due to their promising stability. However, the efficiency of solar cells based on RPPs is much lower than that based on 3D perovskites, mainly attributed to their poor charge transport. Herein, a simple yet universal method for controlling the quality of RPP films by a synergistic effect of two additives in the precursor solution is presented. RPP films achieved by this method show (a) high quality with uniform morphology, enhanced crystallinity, and reduced density of sub-bandgap states, (b) vertically oriented perovskite frameworks that facilitate efficient charge transport, and (c) type-II band alignment that favors self-driven charge separation. Consequently, a hysteresis-free RPP solar cell with a power conversion efficiency exceeding 12%, which is much higher than that of the control device (1.5%), is achieved. The findings will spur new developments in the fabrication of high-quality, aligned, and graded RPP films essential for realizing efficient and stable perovskite solar cells.

  • 43.
    Lin, Yuze
    et al.
    Peking Univ, Peoples R China.
    Zhao, Fuwen
    Chinese Acad Sci, Peoples R China.
    Prasad, Shyamal K. K.
    Victoria Univ Wellington, New Zealand.
    Chen, Jing-De
    Soochow Univ, Peoples R China.
    Wanzhu, Cai
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Zhang, Qianqian
    Univ North Carolina Chapel Hill, NC 27599 USA.
    Chen, Kai
    Victoria Univ Wellington, New Zealand.
    Wu, Yang
    Xi An Jiao Tong Univ, Peoples R China.
    Ma, Wei
    Xi An Jiao Tong Univ, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Tang, Jian-Xin
    Soochow Univ, Peoples R China.
    Wang, Chunru
    Chinese Acad Sci, Peoples R China.
    You, Wei
    Univ North Carolina Chapel Hill, NC 27599 USA.
    Hodgkiss, Justin M.
    Victoria Univ Wellington, New Zealand.
    Zhan, Xiaowei
    Peking Univ, Peoples R China.
    Balanced Partnership between Donor and Acceptor Components in Nonfullerene Organic Solar Cells with > 12% Efficiency2018Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 30, nr 16, artikel-id 1706363Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Relative to electron donors for bulk heterojunction organic solar cells (OSCs), electron acceptors that absorb strongly in the visible and even near-infrared region are less well developed, which hinders the further development of OSCs. Fullerenes as traditional electron acceptors have relatively weak visible absorption and limited electronic tunability, which constrains the optical and electronic properties required of the donor. Here, high-performance fullerene-free OSCs based on a combination of a medium-bandgap polymer donor (FTAZ) and a narrow-bandgap nonfullerene acceptor (IDIC), which exhibit complementary absorption, matched energy levels, and blend with pure phases on the exciton diffusion length scale, are reported. The single-junction OSCs based on the FTAZ:IDIC blend exhibit power conversion efficiencies up to 12.5% with a certified value of 12.14%. Transient absorption spectroscopy reveals that exciting either the donor or the acceptor component efficiently generates mobile charges, which do not suffer from recombination to triplet states. Balancing photocurrent generation between the donor and nonfullerene acceptor removes undesirable constraints on the donor imposed by fullerene derivatives, opening a new avenue toward even higher efficiency for OSCs.

  • 44.
    Puttisong, Yuttapoom
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Xia, Yuxin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Chen, X.
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Buyanova, Irina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Chen, Weimin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Charge Generation via Relaxed Charge-Transfer States in Organic Photovoltaics by an Energy-Disorder-Driven Entropy Gain2018Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, nr 24, s. 12640-12646Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In organic photovoltaics, efficient charge generation relies on our ability to convert excitons into free charges. Efficient charge separation from "energetic excitons" has been understood to be governed by delocalization effects promoted by molecular aggregation. A remaining puzzle is, however, the mechanism underlying charge generation via relaxed interfacial charge-transfer (CT) excitons that also exhibit an internal quantum efficiency close to unity. Here, we provide evidence for efficient charge generation via CT state absorption over a temperature range of 50-300 K, despite an intrinsically strong Coulomb binding energy of about 400 meV that cannot be modified by fullerene aggregation. We explain our observation by entropy-driven charge separation, with a key contribution from energy disorder. The energy disorder reduces the charge generation barrier by substantially gaining the entropy as electron hole distance increases, resulting in efficient CT exciton dissociation. Our results underline an emerging consideration of energy disorder in thermodynamic stability of charge pairs and highlight the energy disorder as a dominant factor for generating charges via the CT state. A discussion for a trade-off in harvesting charges from relaxed CT excitons is also provided.

  • 45.
    Zhang, Jiangbin
    et al.
    Univ Cambridge, England; Imperial Coll London, England.
    Kan, Bin
    Nankai Univ, Peoples R China.
    Pearson, Andrew J.
    Univ Cambridge, England.
    Parnell, Andrew J.
    Univ Sheffield, England.
    Cooper, Joshaniel F. K.
    Rutherford Appleton Lab, England.
    Liu, Xiaoke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Univ Cambridge, England.
    Conaghan, Patrick J.
    Univ Cambridge, England.
    Hopper, Thomas R.
    Imperial Coll London, England.
    Wu, Yutian
    Univ Cambridge, England.
    Wan, Xiangjian
    Nankai Univ, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Greenham, Neil C.
    Univ Cambridge, England.
    Bakulin, Artem A.
    Imperial Coll London, England.
    Chen, Yongsheng
    Nankai Univ, Peoples R China.
    Friend, Richard H.
    Univ Cambridge, England.
    Correction: Efficient non-fullerene organic solar cells employing sequentially deposited donor–acceptor layers(vol 6, pg 18225, 2018)2018Ingår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, nr 43, s. 21618-21618Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Correction for Efficient non-fullerene organic solar cells employing sequentially deposited donor-acceptor layers by Jiangbin Zhang et al., J. Mater. Chem. A, 2018, 6, 18225-18233.

  • 46.
    Yao, Huifeng
    et al.
    Chinese Acad Sci, Peoples R China.
    Qian, Deping
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Zhang, Hao
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Qin, Yunpeng
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Xu, Bowei
    Chinese Acad Sci, Peoples R China.
    Cui, Yong
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Yu, Runnan
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Hou, Jianhui
    Chinese Acad Sci, Peoples R China; Univ Chinese Acad Sci, Peoples R China.
    Critical Role of Molecular Electrostatic Potential on Charge Generation in Organic Solar Cells2018Ingår i: Chinese journal of chemistry, ISSN 1001-604X, E-ISSN 1614-7065, Vol. 36, nr 6, s. 491-494Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Revealing the charge generation is a crucial step to understand the organic photovoltaics. Recent development in non-fullerene organic solar cells (OSCs) indicates efficient charge separation even with negligible energetic offset between the donor and acceptor materials. These new findings trigger a critical question concerning the charge separation mechanism in OSCs, traditionally believed to result from sufficient energetic offset between the polymer donor and fullerene acceptor. We propose a new mechanism, which involves the molecular electrostatic potential, to explain efficient charge separation in non-fullerene OSCs. Together with the new mechanism, we demonstrate a record efficiency of similar to 12% for systems with negligible energetic offset between donor and acceptor materials. Our analysis also rationalizes different requirement of the energetic offset between fullerene-based and non-fullerene OSCs, and paves the way for further design of OSC materials with both high photocurrent and high photovoltage at the same time.

  • 47.
    Qian, Deping
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Zheng, Zilong
    Georgia Inst Technol, GA 30332 USA; Georgia Inst Technol, GA 30332 USA.
    Yao, Huifeng
    Chinese Acad Sci, Peoples R China.
    Tress, Wolfgang
    Ecole Polytech Fed Lausanne, Switzerland.
    Hopper, Thomas R.
    Imperial Coll London, England.
    Chen, Shula
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Li, Sunsun
    Chinese Acad Sci, Peoples R China.
    Liu, Jing
    Hong Kong Univ Sci and Technol, Peoples R China; Hong Kong Univ Sci and Technol, Peoples R China.
    Chen, Shangshang
    Hong Kong Univ Sci and Technol, Peoples R China; Hong Kong Univ Sci and Technol, Peoples R China.
    Zhang, Jiangbin
    Imperial Coll London, England; Univ Cambridge, England.
    Liu, Xiaoke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Gao, Bowei
    Chinese Acad Sci, Peoples R China.
    Ouyang, Liangqi
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Jin, Yingzhi
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Pozina, Galia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska fakulteten.
    Buyanova, Irina
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Chen, Weimin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska fakulteten.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Coropceanu, Veaceslav
    Georgia Inst Technol, GA 30332 USA; Georgia Inst Technol, GA 30332 USA.
    Bredas, Jean-Luc
    Georgia Inst Technol, GA 30332 USA; Georgia Inst Technol, GA 30332 USA.
    Yan, He
    Hong Kong Univ Sci and Technol, Peoples R China; Hong Kong Univ Sci and Technol, Peoples R China.
    Hou, Jianhui
    Chinese Acad Sci, Peoples R China.
    Zhang, Fengling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Bakulin, Artem A.
    Imperial Coll London, England.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Design rules for minimizing voltage losses in high-efficiency organic solar cells2018Ingår i: Nature Materials, ISSN 1476-1122, E-ISSN 1476-4660, Vol. 17, nr 8, s. 703-+Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The open-circuit voltage of organic solar cells is usually lower than the values achieved in inorganic or perovskite photovoltaic devices with comparable bandgaps. Energy losses during charge separation at the donor-acceptor interface and non-radiative recombination are among the main causes of such voltage losses. Here we combine spectroscopic and quantum-chemistry approaches to identify key rules for minimizing voltage losses: (1) a low energy offset between donor and acceptor molecular states and (2) high photoluminescence yield of the low-gap material in the blend. Following these rules, we present a range of existing and new donor-acceptor systems that combine efficient photocurrent generation with electroluminescence yield up to 0.03%, leading to non-radiative voltage losses as small as 0.21 V. This study provides a rationale to explain and further improve the performance of recently demonstrated high-open-circuit-voltage organic solar cells.

  • 48.
    Wang, Heyong
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Yu, Hongling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Liu, Xiaoke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Efficient Light-Emitting Diodes Based on In-Situ Self-Assembled Perovskite Nanocrystals2018Ingår i: ORGANIC LIGHT EMITTING MATERIALS AND DEVICES XXII, SPIE-INT SOC OPTICAL ENGINEERING , 2018, Vol. 10736, artikel-id UNSP 107361FKonferensbidrag (Refereegranskat)
    Abstract [en]

    We introduce a simple and low-cost approach -drop-coating method -for preparation of in-situ self-assembled perovskite nanocrystals for efficient light-emitting diodes. The PL spectrum of the self-assembled NFPI4 nanocrystals thin film prepared by the drop-coating method shows blue shift compared with that of the typical NFPI4 thin film prepared by spin-coating method. In addition, the PL spectra of these self-assembled nanocrystals are tuned from 765 nm to 725 nm by changing usage amounts of the perovskite precursor solution. More importantly, efficient light-emitting diodes with EQEs up to 6.8% are achieved based on these self-assembled NFPI4 nanocrystals.

  • 49.
    Wang, Heyong
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Yu, Hongling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Liu, Xiaoke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Efficient light-emitting diodes based on in-situ self-assembled perovskite nanocrystals2018Ingår i: JOURNAL OF PHOTONICS FOR ENERGY, ISSN 1947-7988, Vol. 8, nr 4, artikel-id 046002Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We introduce a simple and low-cost approach-drop-coating method-for preparation of in-situ self-assembled perovskite nanocrystals for efficient light-emitting diodes (LEDs). The photoluminescence (PL) spectrum of the self-assembled NFPI4 nanocrystals thin film prepared by the drop-coating method shows blue shift compared with that of the typical NFPI4 thin film prepared by the spin-coating method. In addition, the PL spectra of these self-assembled nanocrystals are tuned from 765 to 725 nm by changing usage amounts of the perovskite precursor solution. More importantly, efficient LEDs with external quantum efficiencies up to 6.8% are achieved based on these self-assembled NFPI4 nanocrystals. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)

  • 50.
    Zhang, Jiangbin
    et al.
    Univ Cambridge, England; Imperial Coll London, England.
    Kan, Bin
    Nankai Univ, Peoples R China.
    Pearson, Andrew J.
    Univ Cambridge, England.
    Parnell, Andrew J.
    Univ Sheffield, England.
    Cooper, Joshaniel F. K.
    Rutherford Appleton Lab, England.
    Liu, Xiaoke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten. Univ Cambridge, England.
    Conaghan, Patrick J.
    Univ Cambridge, England.
    Hopper, Thomas R.
    Imperial Coll London, England.
    Wu, Yutian
    Imperial Coll London, England.
    Wan, Xiangjian
    Nankai Univ, Peoples R China.
    Gao, Feng
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska fakulteten.
    Greenham, Neil C.
    Univ Cambridge, England.
    Bakulin, Artem A.
    Imperial Coll London, England.
    Chen, Yongsheng
    Nankai Univ, Peoples R China.
    Friend, Richard H.
    Univ Cambridge, England.
    Efficient non-fullerene organic solar cells employing sequentially deposited donor-acceptor layers2018Ingår i: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, nr 37, s. 18225-18233Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Non-fullerene acceptors (NFAs) have recently outperformed their fullerene counterparts in binary bulk-heterojunction (BHJ) organic solar cells (OSCs). Further development of NFA OSCs may benefit other novel OSC device structures that alter or extend the standard BHJ concept. Here, we report such a new processing route that forms a BHJ-like morphology between sequentially processed polymer donor and NFA with high power conversion efficiencies in excess of 10%. Both devices show similar charge generation and recombination behaviours, supporting formation of similar BHJ active layers. We correlate the approximate to 30 meV smaller open-circuit voltage in sq-BHJ devices to more substantial non-radiative recombination by voltage loss analysis. We also determine the exciton diffusion length of benchmark polymer PBDB-T to be 10 +/- 3 nm. Our results demonstrate high-efficiency OSC devices using sequential deposition method and provide new opportunities to further improve performance of state-of-the-art OSCs.

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