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Wang, Suhao
Publications (4 of 4) Show all publications
James, D. I., Wang, S., Ma, W., Hedstrom, S., Meng, X., Persson, P., . . . Wang, E. (2016). High-Performance Hole Transport and Quasi-Balanced Ambipolar OFETs Based on D-A-A Thieno-benzo-isoindigo Polymers. ADVANCED ELECTRONIC MATERIALS, 2(4), 1500313
Open this publication in new window or tab >>High-Performance Hole Transport and Quasi-Balanced Ambipolar OFETs Based on D-A-A Thieno-benzo-isoindigo Polymers
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2016 (English)In: ADVANCED ELECTRONIC MATERIALS, ISSN 2199-160X, Vol. 2, no 4, p. 1500313-Article in journal (Refereed) Published
Abstract [en]

Two new conjugated polymers are synthesized based on a novel donor-acceptor-acceptor (D-A-A) design strategy with the intention of attaining lower lowest unoccupied molecular obital levels compared to the normally used D-A strategy. By coupling two thieno-benzo-isoindigo units together via the phenyl position to give a new symmetric benzene-coupled di-thieno-benzo-isoindigo (BdiTBI) monomer as an A-A acceptor and thiophene (T) or bithiophene (2T) as a donor, two new polymers PT-BdiTBI and P2T-BdiTBI are synthesized via Stille coupling. The two polymers are tested in top gate and top contact field effect transistors, which exhibit balanced ambipolar charge transport properties with poly(methyl methacrylate) as dielectric and a high hole mobility up to 1.1 cm(2) V-1 s(-1) with poly(trifluoroethylene) as dielectric. The polymer films are investigated using atomic force microscopy, which shows fibrous features due to their high crystallinity as indicated by grazing incidence wide-angle X-ray scattering. The theoretical calculations agree well with the experimental data on the energy levels. It is demonstrated that the D-A-A strategy is very effective for designing low band gap polymers for organic electronic applications.

Place, publisher, year, edition, pages
WILEY-BLACKWELL, 2016
Keywords
ambipolar; conjugated polymers; donor-acceptor-acceptor strategy; high mobility; organic field effect transistors
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-128962 (URN)10.1002/aelm.201500313 (DOI)000374335800004 ()
Note

Funding Agencies|Swedish Research Council; Swedish Energy Agency; EU projects SUNFLOWER "SUstainable Novel FLexible Organic Watts Efficiently Reliable" [FP7-ICT-2011-7, 287594]; National Natural Science Foundation of China [21504066]; Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy [DE-AC02-05CH11231]

Available from: 2016-06-09 Created: 2016-06-07 Last updated: 2017-02-03
Wang, S., Fabiano, S., Himmelberger, S., Puzinas, S., Crispin, X., Salleo, A. & Berggren, M. (2015). Experimental evidence that short-range intermolecular aggregation is sufficient for efficient charge transport in conjugated polymers. Proceedings of the National Academy of Sciences of the United States of America, 112(34), 10599-10604
Open this publication in new window or tab >>Experimental evidence that short-range intermolecular aggregation is sufficient for efficient charge transport in conjugated polymers
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2015 (English)In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 112, no 34, p. 10599-10604Article in journal (Refereed) Published
Abstract [en]

Efficiency, current throughput, and speed of electronic devices are to a great extent dictated by charge carrier mobility. The classic approach to impart high carrier mobility to polymeric semiconductors has often relied on the assumption that extensive order and crystallinity are needed. Recently, however, this assumption has been challenged, because high mobility has been reported for semiconducting polymers that exhibit a surprisingly low degree of order. Here, we show that semiconducting polymers can be confined into weakly ordered fibers within an inert polymer matrix without affecting their charge transport properties. In these conditions, the semiconducting polymer chains are inhibited from attaining long-range order in the p-stacking or alkyl-stacking directions, as demonstrated from the absence of significant X-ray diffraction intensity corresponding to these crystallographic directions, yet still remain extended along the backbone direction and aggregate on a local length scale. As a result, the polymer films maintain high mobility even at very low concentrations. Our findings provide a simple picture that clarifies the role of local order and connectivity of domains.

Place, publisher, year, edition, pages
National Academy of Sciences, 2015
Keywords
organic electronics; conjugated polymers; aggregation; charge transport
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-121306 (URN)10.1073/pnas.1501381112 (DOI)000360005600036 ()26261305 (PubMedID)
Note

Funding Agencies|Advanced Functional Materials Center at Linkoping University; Onnesjo Foundation; Knut and Alice Wallenberg Foundation; Swedish Foundation for Strategic Research; Swedish Governmental Agency for Innovation Systems (VINNOVA); National Science Foundation [DMR 1205752]; US Department of Energy, Office of Science, Office of Basic Energy Sciences [DE-AC02-76SF00515]

Available from: 2015-09-16 Created: 2015-09-14 Last updated: 2017-12-04
Qian, D., Liu, B., Wang, S., Himmelberger, S., Linares, M., Vagin, M., . . . Zhang, F. (2015). Modulating molecular aggregation by facile heteroatom substitution of diketopyrrolopyrrole based small molecules for efficient organic solar cells. Journal of Materials Chemistry A, 3(48), 24349-24357
Open this publication in new window or tab >>Modulating molecular aggregation by facile heteroatom substitution of diketopyrrolopyrrole based small molecules for efficient organic solar cells
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2015 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, no 48, p. 24349-24357Article in journal (Refereed) Published
Abstract [en]

In conjugated polymers and small molecules of organic solar cells, aggregation induced by intermolecular interactions governs the performance of photovoltaics. However, little attention has been paid to the connection between molecular structure and aggregation within solar cells based on soluble small molecules. Here we demonstrate modulation of intermolecular aggregation of two synthesized molecules through heteroatom substitution to develop an understanding of the role of aggregation in conjugated molecules. Molecule 1 (M1) based on 2-ethylhexyloxy-benzene substituted benzo[1,2-b:4,5-b]dithiophene (BDTP) and diketopyrrolopyrrole (DPP) displays strong aggregation in commonly used organic solvents, which is reduced in molecule 2 (M2) by facile oxygen atom substitution on the BDTP unit confirmed by absorption spectroscopy and optical microscopy, while it successfully maintains molecular planarity and favorable charge transport characteristics. Solar cells based on M2 exhibit more than double the photocurrent of devices based on M1 and yield a power conversion efficiency of 5.5%. A systematic investigation of molecular conformation, optoelectronic properties, molecular packing and crystallinity as well as film morphology reveals structure dependent aggregation responsible for the performance difference between the two conjugated molecules.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2015
National Category
Biological Sciences Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:liu:diva-123846 (URN)10.1039/c5ta06501a (DOI)000366163000022 ()
Note

Funding Agencies|Swedish Energy Agency; China Scholarship Council (CSC)

Available from: 2016-01-11 Created: 2016-01-11 Last updated: 2017-12-01
Li, W., Wang, D., Wang, S., Ma, W., Hedstrom, S., Ian James, D., . . . Wang, E. (2015). One-Step Synthesis of Precursor Oligomers for Organic Photovoltaics: A Comparative Study between Polymers and Small Molecules. ACS Applied Materials and Interfaces, 7(49), 27106-27114
Open this publication in new window or tab >>One-Step Synthesis of Precursor Oligomers for Organic Photovoltaics: A Comparative Study between Polymers and Small Molecules
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2015 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, no 49, p. 27106-27114Article in journal (Refereed) Published
Abstract [en]

Two series of oligomers TQ and rhodanine end-capped TQ-DR were synthesized using a facile one-step method. Their optical, electrical, and thermal properties and photovoltaic performances were systematically investigated and compared. The TQ series of oligomers were found to be amorphous, whereas the TQ-DR series are semicrystalline. For the TQ oligomers, the results obtained in solar cells show that as the chain length of the oligomers increases, an increase in power conversion efficiency (PCE) is obtained. However, when introducing 3-ethylrhodanine into the TQ oligomers as end groups, the PCE of the TQ-DR series of oligomers decreases as the chain length increases. Moreover, the TQ-DR series of oligomers give much higher performances compared to the original amorphous TQ series of oligomers owing to the improved extinction coefficient (epsilon) and crystallinity afforded by the rhodanine. In particular, the highly crystalline oligomer TQ5-DR, which has the shortest conjugation length shows a high hole mobility of 0.034 cm(2) V-1 s(-1) and a high PCE of 3.14%, which is the highest efficiency out of all of the six oligomers. The structure-property correlations for all of the oligomers and the TQ1 polymer demonstrate that structural control of enhanced intermolecular interactions and crystallinity is a key for small molecules/oligomers to achieve high mobilities, which is an essential requirement for use in OPVs.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2015
Keywords
crystallinity; amorphous; one-step method; oligomers; hole mobility; organic photovoltaics
National Category
Electrical Engineering, Electronic Engineering, Information Engineering Biological Sciences
Identifiers
urn:nbn:se:liu:diva-123746 (URN)10.1021/acsami.5b09460 (DOI)000366873900011 ()
Note

Funding Agencies|China Scholarship Council; program for the Excellent Doctoral Dissertations of Guangdong Province [ybzzxm201114]; Guangdong Natural Science Foundation [S2012030006232]; Office of Science, Office of Basic Energy Sciences of the U.S. Department of Energy [DE-AC02-05CH11231]

Available from: 2016-01-11 Created: 2016-01-11 Last updated: 2018-02-27
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