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  • 201.
    David, Denis
    et al.
    Universidade Federal da Bahia, Campus Ondina, Salvador-Ba, Brazil.
    Alnoor, Hatim
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Mancir da Silva Santana, Victor
    Universidade Federal da Bahia, Campus Ondina, Salvador-Ba, Brazil.
    Bargiela, Pascal
    Royal Institute of Technology, Stockholm, Sweden.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Baldissera, Gustavo
    Royal Institute of Technology, Stockholm, Sweden.
    Persson, Clas
    Royal Institute of Technology, Stockholm, Sweden; University of Oslo, Oslo, Norway.
    Ferreira da Silva, Antonio
    Universidade Federal da Bahia, Campus Ondina, Salvador-Ba, Brazil.
    Optical properties from photoelectron energy-loss spectroscopy of low-temperature aqueous chemically synthesized ZnO nanorods grown on Si2019In: Semiconductor Science and Technology, ISSN 0268-1242, E-ISSN 1361-6641, Vol. 34, no 4, article id 045019Article in journal (Refereed)
    Abstract [en]

    The optical properties of zinc oxide (ZnO) nanorods (NRs) synthesized by the low-temperature aqueous chemical method on top of silicon (Si) substrate have been investigated by means of photoelectron energy loss spectroscopy (PEELS). The ZnO NRs were obtained by the low temperature aqueous chemical synthesis on top of Si substrate. The measured valence band, the dynamical dielectric functions and optical absorption of the material show a reasonable agreement when the trending and shape of the theoretical calculations are considered. A first-principle calculation based on density functional theory (DFT) was performed using the partially self-consistent GW approximation (scGW0) and compared to the experimental results. The application of these two techniques brings a new analysis of the electronic properties of this material. The experimental results regarding the density of states (DOS) obtained for the valence band using x-ray photoelectron spectroscopy (XPS) was found to be consistent with the theoretical calculated value. Due to this consistency, the same wavefunctions was then employed to calculate the dielectric function of the ZnO NRs. The experimentally extracted dielectric function was also consistent with the calculated values.

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  • 202.
    del Pozo, Freddy G.
    et al.
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Pfattner, Raphael
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Georgakopoulos, Stamatis
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Galindo, Sergi
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Veciana, Jaume
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Rovira, Concepcio
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Mas-Torrent, Marta
    Institute Ciencia Mat Barcelona ICMAB CSIC, Spain; Networking Research Centre Bioengn Biomat and Nanomed CIBER, Spain.
    Single Crystal-Like Performance in Solution-Coated Thin-Film Organic Field-Effect Transistors2016In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 26, no 14, p. 2379-2386Article in journal (Refereed)
    Abstract [en]

    In electronics, the field-effect transistor (FET) is a crucial cornerstone and successful integration of this semiconductor device into circuit applications requires stable and ideal electrical characteristics over a wide range of temperatures and environments. Solution processing, using printing or coating techniques, has been explored to manufacture organic field-effect transistors (OFET) on flexible carriers, enabling radically novel electronics applications. Ideal electrical characteristics, in organic materials, are typically only found in single crystals. Tiresome growth and manipulation of these hamper practical production of flexible OFETs circuits. To date, neither devices nor any circuits, based on solution-processed OFETs, has exhibited an ideal set of characteristics similar or better than todays FET technology based on amorphous silicon. Here, bar-assisted meniscus shearing of dibenzo-tetrathiafulvalene to coat-process self-organized crystalline organic semiconducting domains with high reproducibility is reported. Including these coatings as the channel in OFETs, electric field and temperature-independent charge carrier mobility and no bias stress effects are observed. Furthermore, record-high gain in OFET inverters and exceptional operational stability in both air and water are measured.

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  • 203.
    Demchyshyn, Stepan
    et al.
    Johannes Kepler University of Linz, Austria; Johannes Kepler University of Linz, Austria; LIT, Austria.
    Melanie Roemer, Janina
    Ludwig Maximilians University of Munchen, Germany; Ludwig Maximilians University of Munchen, Germany.
    Groiss, Heiko
    Johannes Kepler University of Linz, Austria; Johannes Kepler University of Linz, Austria.
    Heilbrunner, Herwig
    Johannes Kepler University of Linz, Austria.
    Ulbricht, Christoph
    Johannes Kepler University of Linz, Austria; Johannes Kepler University of Linz, Austria.
    Apaydin, Dogukan
    Johannes Kepler University of Linz, Austria.
    Boehm, Anton
    Ludwig Maximilians University of Munchen, Germany; Ludwig Maximilians University of Munchen, Germany.
    Ruett, Uta
    DESY, Germany.
    Bertram, Florian
    DESY, Germany.
    Hesser, Guenter
    Johannes Kepler University of Linz, Austria.
    Clark Scharber, Markus
    Johannes Kepler University of Linz, Austria.
    Serdar Sariciftci, Niyazi
    Johannes Kepler University of Linz, Austria.
    Nickel, Bert
    Ludwig Maximilians University of Munchen, Germany; Ludwig Maximilians University of Munchen, Germany; Nanosyst Initiat Munich, Germany.
    Bauer, Siegfried
    Johannes Kepler University of Linz, Austria.
    Glowacki, Eric
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Kaltenbrunner, Martin
    Johannes Kepler University of Linz, Austria; LIT, Austria.
    Confining metal-halide perovskites in nanoporous thin films2017In: Science Advances, ISSN 0036-8156, E-ISSN 2375-2548, Vol. 3, no 8, article id e1700738Article in journal (Refereed)
    Abstract [en]

    Controlling the size and shape of semiconducting nanocrystals advances nanoelectronics and photonics. Quantumconfined, inexpensive, solution-derived metal halide perovskites offer narrowband, color-pure emitters as integral parts of next-generation displays and optoelectronic devices. We use nanoporous silicon and alumina thin films as templates for the growth of perovskite nanocrystallites directly within device-relevant architectures without the use of colloidal stabilization. We find significantly blue-shifted photoluminescence emission by reducing the pore size; normally infrared-emitting materials become visibly red, and green-emitting materials become cyan and blue. Confining perovskite nanocrystals within porous oxide thin films drastically increases photoluminescence stability because the templates auspiciously serve as encapsulation. We quantify the template-induced size of the perovskite crystals in nanoporous silicon with microfocus high-energy x-ray depth profiling in transmission geometry, verifying the growth of perovskite nanocrystals throughout the entire thickness of the nanoporous films. Low-voltage electroluminescent diodes with narrow, blue-shifted emission fabricated from nanocrystalline perovskites grown in embedded nanoporous alumina thin films substantiate our general concept for next-generation photonic devices.

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  • 204.
    Derek, Vedran
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Jakesova, Marie
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Simon, Daniel
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Glowacki, Eric
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Micropatterning of organic electronic materials using a facile aqueous photolithographic process2018In: AIP Advances, ISSN 2158-3226, E-ISSN 2158-3226, Vol. 8, no 10, article id 105116Article in journal (Refereed)
    Abstract [en]

    Patterning organic semiconductors via traditional solution-based microfabrication techniques is precluded by undesired interactions between processing solvents and the organic material. Herein we show how to avoid these problems easily and introduce a simple lift-off method to pattern organic semiconductors. Positive tone resist is deposited on the substrate, followed by conventional exposure and development. After deposition of the organic semiconductor layer, the remaining photoresist is subjected to a flood exposure, rendering it developable. Lift-off is then performed using the same aqueous developer as before. We find that the aqueous developers do not compromise the integrity of the organic layer or alter its electronic performance. We utilize this technique to pattern four different organic electronic materials: epindo-lidione (EPI), a luminescent semiconductor, p-n photovoltaic bilayers of metal-free phthalocyanine and N, N-dimethyltetracarboxylic diimide, and finally the archetypical conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT). The result of our efforts is a facile method making use of well-established techniques that can be added to the toolbox of research and industrial scientists developing organic electronics technology. (c) 2018 Author(s).

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  • 205.
    Diacci, Chiara
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. University of Modena and Reggio Emilia, Italy.
    Berto, Marcello
    University of Modena and Reggio Emilia, Italy; University of Ferrara, Italy.
    Di Lauro, Michele
    University of Modena and Reggio Emilia, Italy.
    Bianchini, Elena
    University of Modena and Reggio Emilia, Italy.
    Pinti, Marcello
    University of Modena and Reggio Emilia, Italy.
    Simon, Daniel
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Biscarini, Fabio
    University of Modena and Reggio Emilia, Italy.
    Bortolotti, Carlo A.
    University of Modena and Reggio Emilia, Italy.
    Label-free detection of interleukin-6 using electrolyte gated organic field effect transistors2017In: Biointerphases, ISSN 1934-8630, E-ISSN 1559-4106, Vol. 12, no 5, article id 05F401Article in journal (Refereed)
    Abstract [en]

    Cytokines are small proteins that play fundamental roles in inflammatory processes in the human body. In particular, interleukin (IL)-6 is a multifunctional cytokine, whose increased levels are associated with infection, cancer, and inflammation. The quantification of IL-6 is therefore of primary importance in early stages of inflammation and in chronic diseases, but standard techniques are expensive, time-consuming, and usually rely on fluorescent or radioactive labels. Organic electronic devices and, in particular, organic field-effect transistors (OFETs) have been proposed in the recent years as novel platforms for label-free protein detection, exploiting as sensing unit surface-immobilized antibodies or aptamers. Here, the authors report two electrolyte-gated OFETs biosensors for IL-6 detection, featuring monoclonal antibodies and peptide aptamers adsorbed at the gate. Both strategies yield biosensors that can work on a wide range of IL-6 concentrations and exhibit a remarkable limit of detection of 1 pM. Eventually, electrolyte gated OFETs responses have been used to extract and compare the binding thermodynamics between the sensing moiety, immobilized at the gate electrode, and IL-6. (C) 2017 American Vacuum Society.

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  • 206.
    DInnocenzo, V.
    et al.
    Ist Italian Tecnol, Italy; Politecn Milan, Italy.
    Luzio, A.
    Ist Italian Tecnol, Italy.
    Abdalla, Hassan
    Linköping University, Department of Physics, Chemistry and Biology, Complex Materials and Devices. Linköping University, Faculty of Science & Engineering.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. University of Groningen, Netherlands.
    Loi, M. A.
    University of Groningen, Netherlands.
    Natali, D.
    Ist Italian Tecnol, Italy; Politecn Milan, Italy.
    Petrozza, A.
    Ist Italian Tecnol, Italy.
    Kemerink, Martijn
    Linköping University, Department of Physics, Chemistry and Biology, Complex Materials and Devices. Linköping University, Faculty of Science & Engineering.
    Caironi, M.
    Ist Italian Tecnol, Italy.
    Two-dimensional charge transport in molecularly ordered polymer field-effect transistors2016In: JOURNAL OF MATERIALS CHEMISTRY C, ISSN 2050-7526, Vol. 4, no 47, p. 11135-11142Article in journal (Refereed)
    Abstract [en]

    Nanometer-thick Langmuir-Schafer monolayers of an electron transporting polymer display charge transport, optical and electro-optical properties that do not depend on the number of layers deposited one above the other. This phenomenon can be rationalized with the micro-structure of the specific multi-layers, which introduces an interlayer hopping penalty confining transport to a neat 2D regime, with a channel not extending beyond a single similar to 3 nm thick polymer strand, as confirmed by kinetic Monte Carlo simulations. Such findings are critical to establish a quantitative structure-property nexus in high mobility polymer semiconductors and in the control of charge transport at a molecular scale.

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  • 207.
    Duong, Le
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    A model to predict the coverage of VHF transmissions2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    VHF står för "Very High Frequency" och är ett frekvensband som ligger i området 30 - 300 MHz. Maritim VHF är standard för Sjöfartsverket och fungerar över hela världen. Det är ett kommunikationssystem som bidrar till ökad säkerhet och kan rädda liv på sjön. Andra vanliga kommunikationssystem som mobiltelefoni fungerar inte tillförlitligt. Idag fungerar mobiltelefoni i stora delar av skärgården och längs kusterna men när det gäller kommunikation mellan fartyg längre ut till havs är den maritima VHF-kommunikationen överlägsen. Sjöfartsverket driver för sitt eget och kunders behov ett mobilradionätverk kallat kustradionätverket. Radiotrafiken i nätet sker både på Very High Frequency (VHF) och Medium frequency (MF). VHF-systemet är ett internationellt system som bland annat används till att kommunicera till sjöss och den trafiken befinner sig i frekvensbandet 155.5 - 162.025 MHz. Inom VHF-bandet finns det 55 kanaler. Kanalerna vid kustradiostationen kallas för duplexkanaler och innebär att kustradiostationerna sänder och tar emot signaler på två olika frekvenser. Radioutbredningen hos antennen som är installerad på basstationen har riktverkan i vissa riktningar och dämpningar i andra. Detta kan ses i strålningsdiagrammet under kapitlet "Täckningsmodell" och avsnittet antennen. Andra faktorer som kan påverka radioutbredningen är förluster i basstationenssystemet, topologin hos området mellan sändare och mottagare samt väderberoende utbredningsegenskaper. Genom att hitta de tänkbara faktorer som påverkar signalutbredningen kan en täckningsmodell förutses. Det är förluster som finns i basstationen, radiolänken samt förluster vid mottagarantennen.

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  • 208.
    Echresh, Ahmad
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. Shahid Chamran University of Ahvaz, Iran.
    Abbasi, Mazhar Ali
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zargar Shoushtari, Morteza
    Shahid Chamran University of Ahvaz, Iran.
    Farbod, Mansoor
    Shahid Chamran University of Ahvaz, Iran.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Optimization and characterization of NiO thin film and the influence of thickness on the electrical properties of n-ZnO nanorods/p-NiO heterojunction2014In: Semiconductor Science and Technology, ISSN 0268-1242, E-ISSN 1361-6641, Vol. 29, no 11, p. 115009-Article in journal (Refereed)
    Abstract [en]

    In this study, we report on the synthesis optimization of NiO thin film to grow preferentially along the (111) direction. The x-ray diffraction (XRD) pattern revealed that the NiO film with 200 nm thickness annealed at 600 degrees C temperature has the best preferential orientation along the (111) direction. Also, atomic force microscope (AFM) images show that the grain size of NiO increases at higher temperatures. Then, ZnO nanorods were grown on the NiO thin film with 100, 200 and 300 nm thickness grown at 600 degrees C. The XRD pattern and scanning electron microscope (SEM) images indicate that the well-aligned ZnO nanorods with hexagonal face have a preferential orientation along the c-axis (002). The current voltage measurements of the n-ZnO nanorods/p-NiO heterojunctions showed a clear rectifying behavior for all diodes. The threshold voltage of the heterojunctions was increased by increasing the thickness of the NiO thin film which was attributed to the increasing of the series resistance (R-s) of the diodes.

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  • 209.
    Echresh, Ahmad
    et al.
    Shahid Chamran University of Ahvaz, Iran.
    Chey, Chan Oeurn
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zargar Shoushtari, Morteza
    Shahid Chamran University of Ahvaz, Iran.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    UV photo-detector based on p-NiO thin film/n-ZnO nanorods heterojunction prepared by a simple process2015In: Journal of Alloys and Compounds, ISSN 0925-8388, E-ISSN 1873-4669, Vol. 632, p. 165-171Article in journal (Refereed)
    Abstract [en]

    A UV photo-detector based on p-NiO thin film/n-ZnO nanorods heterojunction was fabricated using a simple two-step fabrication process. The aqueous chemical hydrothermal and thermal evaporation methods were combined to grow the ZnO nanorods and the NiO thin film, respectively. Structural investigation indicated that well aligned ZnO nanorods with hexagonal face having a preferential orientation along the c-axis (002) have been achieved and that the NiO thin film is covering all the ZnO nanorods. X-ray photoelectron spectroscopy (XPS) was used to investigate the band alignment of the heterojunction and the valence and the conduction band offsets were determined to be 1.50 eV and 1.83 eV, respectively. The current-voltage characteristics of the p-NiO thin film/ZnO nanorods heterojunction showed a clear rectifying behavior under both dark and UV illumination conditions. The response of the heterojunction diode was excellent regarding the photocurrent generation. Although other similar heterojunction diodes demonstrated lower threshold voltage, the rectification ratio and the sensitivity of the fabricated diode were superior in comparison to other similar heterojunctions reported recently, implying the vitality of the presented two-step process. (C) 2015 Elsevier B.V. All rights reserved.

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  • 210.
    Echresh, Ahmad
    et al.
    Shahid Chamran University of Ahvaz, Iran.
    Chey, Chan Oeurn
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zargar Shoushtari, Morteza
    Shahid Chamran University of Ahvaz, Iran.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Light emitting diode based on n-Zn0.94M0.06O nanorods/p-GaN (M= Cd and Ni) heterojunction under forward and reverse bias2015In: Journal of Luminescence, ISSN 0022-2313, E-ISSN 1872-7883, Vol. 160, p. 305-310Article in journal (Refereed)
    Abstract [en]

    In this study, we report on the improvement in the optoelectronic properties of n-ZnO nanorods/p-GaN heterojunction. This was achieved by doping the ZnO with cadmium (Cd) and nickel (Ni). The ZnO and Zn0.94M0.06O nanorods grown hydrothermally on the p-GaN substrate were used to fabricate the light emitting diodes (LEDs). Structural measurement revealed that nanorods with wurtzite structure having a preferential orientation along the (002) c-axis. The UV-vis spectra show that the optical band gap of Zn0.94M0.06O nanorods is decreased in comparison to ZnO nanorods. Electrical measurements of the fabricated LEDs show an obvious rectifying behaviour with low threshold voltage. Electroluminescence (EL) characteristics of LEDs operated at forward and reverse bias were investigated. The EL spectra under forward bias show that doping ZnO nanorods with Cd and Ni led to an intensity enhancement of the broad peak in the visible region while the blue peak originating from the p-GaN substrate remains almost unaffected. The effect of doping was to reduce the valence band offsets and consequently more hole injection has occurred leading to the observed enhancement of the broad band in the visible region. Under reverse bias all heterojunction LEDs show the blue light emission peak originating from the p-GaN substrate.

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  • 211.
    Echresh, Ahmad
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Echresh, Mohammad
    Sanati Hoveizeh University, Iran.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    High photocurrent gain in NiO thin film/M-doped ZnO nanorods (M = Ag, Cd and Ni) heterojunction based ultraviolet photodiodes2016In: Journal of Luminescence, ISSN 0022-2313, E-ISSN 1872-7883, Vol. 178, p. 324-330Article in journal (Refereed)
    Abstract [en]

    The thermal evaporation method has been used to deposit p-type NiO thin film, which was combined with hydrothermally grown n-type pure and M-doped ZnO nanorods (M=Ag, Cd and Ni) to fabricate a high performance p-n heterojunction ultraviolet photodiodes. The fabricated photodiodes show high rectification ratio and relatively low leakage current. The p-NiO/n-Zn0.94Ag0.06O heterojunction photo diode displays the highest photocurrent gain (similar to 1.52 x 10(4)), a photoresponsivity of similar to 4.48 x 10(3) AW(-1) and a photosensitivity of similar to 13.56 compared with the other fabricated photodiodes. The predominated transport mechanisms of the p-n heterojunction ultraviolet photodiodes at low and high applied forward bias may be recombination-tunneling and space charge limited current, respectively. (C) 2016 Elsevier B.V. All rights reserved.

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  • 212.
    Echresh, Ahmad
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. Shahid Chamran University of Ahvaz, Iran.
    Oeurn Chey, Chan
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Zargar Shoushtari, Morteza
    Shahid Chamran University of Ahvaz, Iran.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Tuning the emission of ZnO nanorods based light emitting diodes using Ag doping2014In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 116, no 19, p. 2-9Article in journal (Refereed)
    Abstract [en]

    We have fabricated, characterized, and compared ZnO nanorods/p-GaN and n-Zn0.94Ag0.06O nanorods/p-GaN light emitting diodes (LEDs). Current-voltage measurement showed an obvious rectifying behaviour of both LEDs. A reduction of the optical band gap of the Zn0.94Ag0.06O nanorods compared to pure ZnO nanorods was observed. This reduction leads to decrease the valence band offset at n-Zn0.94Ag0.06O nanorods/p-GaN interface compared to n-ZnO nanorods/p-GaN heterojunction. Consequently, this reduction leads to increase the hole injection from the GaN to the ZnO. From electroluminescence measurement, white light was observed for the n-Zn0.94Ag0.06O nanorods/p-GaN heterojunction LEDs under forward bias, while for the reverse bias, blue light was observed. While for the n-ZnO nanorods/p-GaN blue light dominated the emission in both forward and reverse biases. Further, the LEDs exhibited a high sensitivity in responding to UV illumination. The results presented here indicate that doping ZnO nanorods might pave the way to tune the light emission from n-ZnO/p-GaN LEDs.

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  • 213.
    Echresh, Ahmad
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. Shahid Chamran University of Ahvaz, Iran.
    Zargar Shoushtari, Morteza
    Shahid Chamran University of Ahvaz, Iran.
    Farbod, Mansoor
    Shahid Chamran University of Ahvaz, Iran.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Effect of NiO intermediate layer on the optical and electrical properties of n-ZnO nanorods/p-GaAs heterojunction2015In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 119, no 3, p. 1013-1018Article in journal (Refereed)
    Abstract [en]

    ZnO nanorods were grown hydrothermally on bare and NiO-coated p-GaAs substrate to fabricate p-n heterojunctions. The NiO intermediate layer was deposited using thermal evaporation technique. The X-ray diffraction patterns revealed that ZnO nanorods grown on the bare p-GaAs do not have any preferential orientation along the c-axis, but those on the NiO-coated p-GaAs have preferential orientation along the c-axis, i.e. along the (002) direction. The scanning electron microscope images show that the NiO intermediate layer improved the uniformity and the alignment of the ZnO nanorods. Photoluminescence spectra demonstrated that increasing the thickness of NiO intermediate layer leads to improve the optical quality of the ZnO nanorods. Current-voltage characteristics showed that the presence of the NiO intermediate layer leads to increase the threshold voltage and decrease the leakage current of the n-ZnO nanorods/p-GaAs heterojunction. The energy band diagram of heterojunctions drown using Anderson model revealed that the NiO intermediate layer acts as an electron-blocking layer in the ZnO side and at the same time increases the hole injection from the GaAs to the ZnO side. Therefore, most of electron-hole pair recombination could occur at the ZnO site.

  • 214.
    Eckstein, Brian J.
    et al.
    Northwestern University, IL 60208 USA.
    Melkonyan, Ferdinand S.
    Northwestern University, IL 60208 USA.
    Manley, Eric F.
    Northwestern University, IL 60208 USA; Argonne National Lab, IL 60439 USA.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Northwestern University, IL 60208 USA.
    Moua, Aidan R.
    Northwestern University, IL 60208 USA.
    Chen, Lin X.
    Northwestern University, IL 60208 USA; Argonne National Lab, IL 60439 USA.
    Facchetti, Antonio
    Northwestern University, IL 60208 USA; Flexterra Corp, IL 60077 USA.
    Marks, Tobin J.
    Northwestern University, IL 60208 USA.
    Naphthalene Bis(4,8-diamino-1,5-dicarboxyl)amide Building Block for Semiconducting Polymers2017In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 139, no 41, p. 14356-14359Article in journal (Refereed)
    Abstract [en]

    We report a new naphthalene bis(4,8-diamino-1,5-dicarboxyl)amide (NBA) building block for polymeric semiconductors. Computational modeling suggests that regio-connectivity at the 2,6- or 3,7-NBA positions strongly modulates polymer backbone torsion and, therefore, intramolecular pi-conjugation and aggregation. Optical, electrochemical, and X-ray diffraction characterization of 3,7- and 2,6-dithienyl-substituted NBA molecules and, corresponding isomeric NBA, bithiophene copolymers P1 and P2, respectively, reveals the key role of regio-connectivity. Charge transport measurements demonstrate that while the twisted 3,7-NDA-based P1 is a poor semiconductor, the planar 2,6-functionalized NBA polymers (P2-P4) exhibit ambipolarity, with mu(e) and mu(h) of up to 0.39 and 0.32 cm(2)/(V.s), respectively.

  • 215. Order onlineBuy this publication >>
    Edberg, Jesper
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Linköping University.
    Flexible and Cellulose-based Organic Electronics2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Organic electronics is the study of organic materials with electronic functionality and the applications of such materials. In the 1970s, the discovery that polymers can be made electrically conductive led to an explosion within this field which has continued to grow year by year. One of the attractive features of organic electronic materials is their inherent mechanical flexibility, which has led to the development of numerous flexible electronics technologies such as organic light emitting diodes and solar cells on flexible substrates. The possibility to produce electronics on flexible substrates like plastic or paper has also had a large impact on the field of printed, electronics where inks with electronic functionality are used for large area fabrication of electronic devices using classical printing methods, such as screen printing, inkjet printing and flexography.

    Recently, there has been a growing interest in the use of cellulose in organic and printed electronics, not only as a paper substrate but also as a component in composite materials where the cellulose provides mechanical strength and favorable 3D-microstructures. Nanofibrillated cellulose is composed of cellulose fibers with high aspect-ratio and diameters in the nanometer range. Due to its remarkable mechanical strength, large area-to-volume ratio, optical transparency and solution processability it has been widely used as a scaffold or binder for electronically active materials in applications such as batteries, supercapacitors and optoelectronics.

    The focus of this thesis is on flexible devices based on conductive polymers and can be divided into two parts: (1) Composite materials of nanofibrillated cellulose and the conductive polymer PEDOT:PSS and (2) patterning of vapor phase polymerized conductive polymers. In the first part, it is demonstrated how the combination of cellulose and conductive polymers can be used to make electronic materials of various form factors and functionality. Thick, freestanding and flexible “papers” are used to realize electrochemical devices such as transistors and supercapacitors while lightweight, porous and elastic aerogels are used for sensor applications. The second focus of the thesis is on a novel method of patterning conductive polymers produced by vapor phase polymerization using UV-light. This method is used to realize flexible electrochromic smart windows with high-resolution images and tunable optical contrast.

    List of papers
    1. An Organic Mixed Ion–Electron Conductor for Power Electronics
    Open this publication in new window or tab >>An Organic Mixed Ion–Electron Conductor for Power Electronics
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    2016 (English)In: Advanced Science, ISSN 2198-3844, article id 1500305Article in journal (Refereed) Published
    Abstract [en]

    A mixed ionic–electronic conductor based on nanofibrillated cellulose composited with poly(3,4-ethylene-dioxythio­phene):­poly(styrene-sulfonate) along with high boiling point solvents is demonstrated in bulky electrochemical devices. The high electronic and ionic conductivities of the resulting nanopaper are exploited in devices which exhibit record values for the charge storage capacitance (1F) in supercapacitors and transconductance (1S) in electrochemical transistors.

    Place, publisher, year, edition, pages
    Wiley-VCH Verlagsgesellschaft, 2016
    National Category
    Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-123225 (URN)10.1002/advs.201500305 (DOI)000370336500011 ()
    Note

    Funding agencies:  Knut and Alice Wallenberg foundation [KAW 2011.0050]; Onnesjo Foundation; Advanced Functional Materials Center at Linkoping University; Stiftelsen for strategisk forskning (SSF); RISE Research Institutes of Sweden; U.S. National Science Foundation [DMR-12

    Available from: 2015-12-08 Created: 2015-12-08 Last updated: 2018-02-15
    2. Thermoelectric Polymers and their Elastic Aerogels
    Open this publication in new window or tab >>Thermoelectric Polymers and their Elastic Aerogels
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    2016 (English)In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 28, no 22, p. 4556-4562Article in journal (Refereed) Published
    Abstract [en]

    Electronically conducting polymers constitute an emerging class of materials for novel electronics, such as printed electronics and flexible electronics. Their properties have been further diversified to introduce elasticity, which has opened new possibility for "stretchable" electronics. Recent discoveries demonstrate that conducting polymers have thermoelectric properties with a low thermal conductivity, as well as tunable Seebeck coefficients - which is achieved by modulating their electrical conductivity via simple redox reactions. Using these thermoelectric properties, all-organic flexible thermoelectric devices, such as temperature sensors, heat flux sensors, and thermoelectric generators, are being developed. In this article we discuss the combination of the two emerging fields: stretchable electronics and polymer thermoelectrics. The combination of elastic and thermoelectric properties seems to be unique for conducting polymers, and difficult to achieve with inorganic thermoelectric materials. We introduce the basic concepts, and state of the art knowledge, about the thermoelectric properties of conducting polymers, and illustrate the use of elastic thermoelectric conducting polymer aerogels that could be employed as temperature and pressure sensors in an electronic-skin.

    Place, publisher, year, edition, pages
    WILEY-V C H VERLAG GMBH, 2016
    National Category
    Polymer Chemistry
    Identifiers
    urn:nbn:se:liu:diva-129660 (URN)10.1002/adma.201505364 (DOI)000377123500029 ()26836440 (PubMedID)
    Note

    Funding Agencies|European Research Council (ERC) [307596]; Swedish Foundation for Strategic Research; Knut and Alice Wallenberg Foundation; Swedish Energy Agency; Advanced Functional Materials Center at Linkoping University; Research Institute of Sweden (RISE)

    Available from: 2016-06-27 Created: 2016-06-23 Last updated: 2018-09-07
    3. Patterning and Conductivity Modulation of Conductive Polymers by UV Light Exposure
    Open this publication in new window or tab >>Patterning and Conductivity Modulation of Conductive Polymers by UV Light Exposure
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    2016 (English)In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 26, no 38, p. 6950-6960Article in journal (Refereed) Published
    Abstract [en]

    A novel patterning technique of conductive polymers produced by vapor phase polymerization is demonstrated. The method involves exposing an oxidant film to UV light which changes the local chemical environment of the oxidant and subsequently the polymerization kinetics. This procedure is used to control the conductivity in the conjugated polymer poly(3,4-ethylenedioxythiophene): tosylate by more than six orders of magnitude in addition to producing high-resolution patterns and optical gradients. The mechanism behind the modulation in the polymerization kinetics by UV light irradiation as well as the properties of the resulting polymer are investigated.

    Place, publisher, year, edition, pages
    WILEY-V C H VERLAG GMBH, 2016
    National Category
    Polymer Chemistry
    Identifiers
    urn:nbn:se:liu:diva-133122 (URN)10.1002/adfm.201601794 (DOI)000386159300010 ()
    Note

    Funding Agencies|Knut and Alice Wallenberg Foundation [KAW 2011.0050, KAW 2014.0041, KAW 2012.0302]

    Available from: 2016-12-12 Created: 2016-12-09 Last updated: 2018-02-15
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  • 216.
    Edberg, Jesper
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Iandolo, Donata
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Brooke, Robert
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Musumeci, Chiara
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Wenzel Andreasen, Jens
    Technical University of Denmark, Denmark.
    Simon, Daniel
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Evans, Drew
    University of South Australia, Australia.
    Engquist, Isak
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Patterning and Conductivity Modulation of Conductive Polymers by UV Light Exposure2016In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 26, no 38, p. 6950-6960Article in journal (Refereed)
    Abstract [en]

    A novel patterning technique of conductive polymers produced by vapor phase polymerization is demonstrated. The method involves exposing an oxidant film to UV light which changes the local chemical environment of the oxidant and subsequently the polymerization kinetics. This procedure is used to control the conductivity in the conjugated polymer poly(3,4-ethylenedioxythiophene): tosylate by more than six orders of magnitude in addition to producing high-resolution patterns and optical gradients. The mechanism behind the modulation in the polymerization kinetics by UV light irradiation as well as the properties of the resulting polymer are investigated.

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    fulltext
  • 217.
    Edberg, Jesper
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. RISE Acreo, Sweden.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Engquist, Isak
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Stellenbosch University, South Africa.
    Boosting the capacity of all-organic paper supercapacitors using wood derivatives2018In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, no 1, p. 145-152Article in journal (Refereed)
    Abstract [en]

    Printed and flexible organic electronics is a steadily expanding field of research and applications. One of the most attractive features of this technology is the possibility of large area and high throughput production to form low-cost electronics on different flexible substrates. With an increasing demand for sustainable energy production, low-cost and large volume technologies to store high-quality energy become equally important. These devices should be environmentally friendly with respect to their entire life cycle. Supercapacitors and batteries based on paper hold great promise for such applications due to the low cost and abundance of cellulose and other forest-derived components. We report a thick-film paper-supercapacitor system based on cellulose nanofibrils, the mixed ion-electron conducting polymer PEDOT: PSS and sulfonated lignin. We demonstrate that the introduction of sulfonated lignin into the cellulose-conducting polymer system increases the specific capacitance from 110 to 230 F g(-1) and the areal capacitance from 160 mF cm(-2) to 1 F cm(-2). By introducing lignosulfonate also into the electrolyte solution, equilibrium, with respect to the concentration of the redox molecule, was established between the electrode and the electrolyte, thus allowing us to perform beyond 700 charge/discharge cycles with no observed decrease in performance.

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  • 218.
    Edberg, Jesper
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Malti, Abdellah
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Granberg, Hjalmar
    RISE Bioeconomy.
    Hamedi, Mahiar M.
    KTH Royal Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Engquist, Isak
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Electrochemical circuits from ‘cut and stick’ PEDOT:PSS-nanocellulose composite2017In: Flexible and printed electronics, E-ISSN 2058-8585, Vol. 4, no 2, article id 045010Article in journal (Refereed)
    Abstract [en]

    We report a flexible self-standing adhesive composite made from PEDOT:PSS and nanofibrillated cellulose. The material exhibits good combined mechanical and electrical characteristics(an elastic modulus of 4.4 MPa, and an electrical conductivity of 30 S cm−1 ). The inherent self-adhesiveness of the material enables it to be laminated and delaminated repeatedly to form and reconfigure devices and circuits. This modular property opens the door for a plethora of applications where reconfigurability and ease-of-manufacturing are of prime importance. We also demonstrate a paper composite with ionic conductivity and combine the two materials to construct electrochemical devices, namely transistors, capacitors and diodes with high values of transconductance, charge storage capacity and current rectification. We have further used these devices to construct digital circuits such as NOT, NAND and NOR logic.

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  • 219.
    Edström, Kristina
    et al.
    School of Education and Communication in Engineering Science, KTH Royal Institute of Technology, Stockholm, Sweden.
    Kolmos, Anette
    Department of Development and Planning, Aalborg University, Aalborg, Denmark.
    Malmi, Lauri
    Department of Computer Science, Aalto University, Helsinki, Finland.
    Bernhard, Jonte
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Andersson, Pernille
    LearningLab DTU, Technical University of Denmark, Kgs. Lyngby, Denmark.
    A bottom-up strategy for establishment of EER in three Nordic countries: The role of networks2018In: European Journal of Engineering Education, ISSN 0304-3797, E-ISSN 1469-5898, Vol. 43, no 2, p. 219-234Article in journal (Refereed)
    Abstract [en]

    This paper investigates the emergence of an engineering education research (EER) community in three Nordic countries: Denmark, Finland and Sweden. First, an overview of the current state of Nordic EER authorship is produced through statistics on international publication. Then, the history of EER and its precursor activities is described in three national narratives. These national storylines are tied together in a description of recent networking activities, aiming to strengthen the EER communities on the Nordic level. Taking these three perspectives together, and drawing on concepts from community of practice theory, network theory and learning network theory, we discuss factors behind the differences in the countries, and draw some conclusions about implications for networking activities in a heterogeneous community. Further, we discuss the role of networks for affording a joint identity.

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  • 220.
    Elhadi Adam, Rania Elhadi
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Synthesis of ZnO nanoparticles by co-precipitation method for solar driven photodegradation of Congo red dye at different pH2018In: PHOTONICS AND NANOSTRUCTURES-FUNDAMENTALS AND APPLICATIONS, ISSN 1569-4410, Vol. 32, p. 11-18Article in journal (Refereed)
    Abstract [en]

    Solar driven photocatalytic processes to remove organic pollutants from wastewater and other aqueous solutions is very important and useful due to its environmental benefits regarding sustainability aspect. In this article, we report a study on the use of bare zinc oxide (ZnO) nanoparticles (NPs) prepared by the chemical low temperature co-precipitation method and used as a catalyst to degrade the Congo red dye from aqueous solution using solar radiation. We performed the photocatalytic experiments for degradation of Congo red dye under solar radiation at different pH values. The results showed that the ZnO NPs are effective under solar radiation for degradation of Congo red dye. Even when the pH was varied down to 4 or raised to 10, the degradation was observed to be slightly improved. This result is due to the excess of radicals species, which enhance the photocatalytic process. In general, the observed degradation efficiency of the ZnO NPs is due to the deep level defects within the band gap that were introduced during the growth process of the ZnO NPs, which enhance the absorption wavelength band towards the visible light region. Recycling of the ZnO NPs for 3 successive runs have indicated the feasibility of reusing the NPs for several times. This implies that by using bare ZnO NPs an efficient approach for degradation of toxic waste can be achieved. Radical scavengers were used to evaluate the role of the radicals in the reaction mechanism.

  • 221.
    Elhadi Adam, Rania
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Mustafa, Elfatih
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Elhag, Sami
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Photocatalytic properties for different metal-oxide nanomaterials2019In: Oxide-based Materials and Devices X, SPIE , 2019, article id 1091925Conference paper (Refereed)
    Abstract [en]

    We here demonstrate the synthesis of different nanostructures, including nanoparticles, nanorods, core-shell structures,and compound metal oxide nanostructures all synthesized by a low temperature chemical process. We furtherinvestigated their photocatalytic properties for degradation of toxic waste and their photochemical efficiency for watersplitting. All the photocatalytic properties as well as the photochemical properties were utilized using sun radiation. Theresults presented indicate huge potential for the investigated processes with positive impact to energy consumption andbenefits for the environment.

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  • 222.
    Elhadi Adam, Rania
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Pirhashemi, Mahsa
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. University of Mohaghegh Ardabili, Ardabil, Iran.
    Elhag, Sami
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Habibi-Yangjeh, Aziz
    University of Mohaghegh Ardabili, Ardabil, Iran.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    ZnO/Ag/Ag2WO4 photo-electrodes with plasmonic behavior for enhanced photoelectrochemical water oxidation2019In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 15, p. 8271-8279Article in journal (Refereed)
    Abstract [en]

    Ag-based compounds are excellent co-catalyst that can enhance harvesting visible light and increase photo-generated charge carrier separation owing to its surface plasmon resonance (SPR) effect in photoelectrochemical (PEC) applications. However, the PEC performance of a ZnO/Ag/Ag2WO4 heterostructure with SPR behavior has not been fully studied so far. Here we report the preparation of a ZnO/Ag/Ag2WO4 photo-electrode with SPR behavior by a low temperature hydrothermal chemical growth method followed by a successive ionic layer adsorption and reaction (SILAR) method. The properties of the prepared samples were investigated by different characterization techniques, which confirm that Ag/Ag2WO4 was deposited on the ZnO NRs. The Ag2WO4/Ag/ZnO photo-electrode showed an enhancement in PEC performance compared to bare ZnO NRs. The observed enhancement is attributed to the red shift of the optical absorption spectrum of the Ag2WO4/Ag/ZnO to the visible region (>400 nm) and to the SPR effect of surface metallic silver (Ag0) particles from the Ag/Ag2WO4 that could generate electron–hole pairs under illumination of low energy visible sun light. Finally, we proposed the PEC mechanism of the Ag2WO4/Ag/ZnO photo-electrode with an energy band structure and possible electron–hole separation and transportation in the ZnO/Ag/Ag2WO4 heterostructure with SPR effect for water oxidation. ER

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  • 223.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain Ibupoto, Zafar
    University of Sindh Jamshoro, Pakistan.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Synthesis of Co3O4 Cotton-Like Nanostructures for Cholesterol Biosensor2015In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 8, no 1, p. 149-161Article in journal (Refereed)
    Abstract [en]

    The use of templates to assist and possess a control over the synthesis of nanomaterials has been an attractive option to achieve this goal. Here we have used sodium dodecyl sulfate (SDS) to act as a template for the low temperature synthesis of cobalt oxide (Co3O4) nanostructures. The use of SDS has led to tune the morphology, and the product was in the form of "cotton-like" nanostructures instead of connected nanowires. Moreover, the variation of the amount of the SDS used was found to affect the charge transfer process in the Co3O4. Using Co3O4 synthesized using the SDS for sensing of cholesterol was investigated. The use of the Co3O4 synthesized using the SDS was found to yield an improved cholesterol biosensor compared to Co3O4 synthesized without the SDS. The improvement of the cholesterol sensing properties upon using the SDS as a template was manifested in increasing the sensitivity and the dynamic range of detection. The results achieved in this study indicate the potential of using template assisted synthesis of nanomaterials in improving some properties, e. g., cholesterol sensing.

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  • 224.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Habit-modifying additives and their morphological consequences on photoluminescence and glucose sensing properties of ZnO nanostructures, grown via aqueous chemical synthesis2015In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 116, p. 21-26Article in journal (Refereed)
    Abstract [en]

    Generally, the anisotropic shape of inorganic nano-crystal can be influenced by one or more of different parameters i.e. kinetic energy barrier, temperature, time, and the nature of the capping molecules. Here, different surfactants acting as capping molecules were used to assist the aqueous chemical growth of zinc oxide (ZnO) nanostructures on Au coated glass substrates. The morphology, crystal quality and the photoluminescence (PL) properties of the ZnO nanostructures were investigated. The PL properties of the prepared ZnO nanostructures at room temperature showed a dominant UV luminescence peak, while the "green yellow" emissions were essentially suppressed. Moreover, the ZnO nanostructures were investigated for the development of a glucose biosensor. An adsorbed molecule has direct contribution on the glucose oxidase/ZnO/Au sensing properties. We show that the performance of a ZnO-based biosensor can be improved by tailoring the properties of the ZnO biomolecule interface through engineering of the morphology, effective surface area, and adsorption capability.

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  • 225.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Dopamine wide range detection sensor based on modified Co3O4 nanowires electrode2014In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 203, p. 543-549Article in journal (Refereed)
    Abstract [en]

    Ultra-thin cobalt oxide (Co3O4) nanowires grown on gold coated glass substrates by the hydrothermal chemical deposition and have been used as a wide range dopamine potentiometric sensor. An anionic surfactant ( sodium dodecylbenzenesulfonate) was used to achieve assisted growth procedure. Moreover, a polymeric membrane containing polyvinyl chloride as plasticized polymer, p-cyclodextrin as ionophore, and potassium tetrakis (4-chlorophenyl) borate as ionic additive were immobilized on the Co3O4 nanostructures through electrostatic adsorption method. X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy were used to characterize the electrodes while ultraviolet-visible absorption was used to investigate the band gap of the Co3O4 nanostructures. The structural characterization showed a cubic crystalline, pure phase, and nanowires morphology of the Co3O4. However, the morphology is altered when the surfactant concentration has been changed. The Co3O4 chemical modified electrodes were used in potentiometric measurements for dopamine in a 10(-2) M acetic acid/sodium acetate solution having a pH of 5.45. For dopamine range from 10(-9) M to 10(-2) M, the potential response of the sensor electrode was linear with a slope of 52 mV/decade. The wide range and high sensitivity of the modified Co3O4 nanowires based sensor for dopamine is attributed to the defects on the metal oxide that is dictated by the used surfactant along with the high surface area-to-volume ratio.

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  • 226.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Incorporating beta-Cyclodextrin with ZnO Nanorods: A Potentiometric Strategy for Selectivity and Detection of Dopamine2014In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 14, no 1, p. 1654-1664Article in journal (Refereed)
    Abstract [en]

    We describe a chemical sensor based on a simple synthesis of zinc oxide nanorods (ZNRs) for the detection of dopamine molecules by a potentiometric approach. The polar nature of dopamine leads to a change of surface charges on the ZNR surface via metal ligand bond formation which results in a measurable electrical signal. ZNRs were grown on a gold-coated glass substrate by a low temperature aqueous chemical growth (ACG) method. Polymeric membranes incorporating beta-cyclodextrin (beta-CD) and potassium tetrakis (4-chlorophenyl) borate was immobilized on the ZNR surface. The fabricated electrodes were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The grown ZNRs were well aligned and exhibited good crystal quality. The present sensor system displays a stable potential response for the detection of dopamine in 10(-2) mol.L-1 acetic acid/sodium acetate buffer solution at pH 5.45 within a wide concentration range of 1 x 10(-6) M-1 x 10(-1) M, with sensitivity of 49 mV/decade. The electrode shows a good response time (less than 10 s) and excellent repeatability. This finding can contribute to routine analysis in laboratories studying the neuropharmacology of catecholamines. Moreover, the metal-ligand bonds can be further exploited to detect DA receptors, and for bio-imaging applications.

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  • 227.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Khun, Kimleang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Efficient Donor Impurities in ZnO Nanorods by Polyethylene Glycol for Enhanced Optical and Glutamate Sensing Properties2016In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 16, no 2Article in journal (Refereed)
    Abstract [en]

    In this paper, we show that the possibility of using polyethylene glycol (EG) as a hydrogen source and it is used to assist the hydrothermal synthesis of ZnO nanorods (ZNRs). EG doping in ZNRs has been found to significantly improve their optical and chemical sensing characteristics toward glutamate. The EG was found to have no role on the structural properties of the ZNRs. However, the x-ray photoelectron spectroscopy (XPS) suggests that the EG could induce donor impurities effect in ZnO. Photoluminescence (PL) and UV-Vis. spectra demonstrated this doping effect. Mott-Schottky analysis at the ZNRs/electrolyte interface was used to investigate the charge density for the doped ZNRs and showed comparable dependence on the used amount of EG. Moreover, the doped ZNRs were used in potentiometric measurements for glutamate for a range from 10(-6) M to 10(-3) M and the potential response of the sensor electrode was linear with a slope of 91.15 mV/decade. The wide range and high sensitivity of the modified ZNRs based glutamate biosensor is attributed to the doping effect on the ZNRs that is dictated by the EG along with the high surface area-to-volume ratio. The findings in the present study suggest new avenues to control the growth of n-ZnO nanostructures and enhance the performance of their sensing devices.

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  • 228.
    Elhag, Sami
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Tordera, Daniel
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Deydier, T
    Department of Material Engineering, University of Toulon, FR-83041 Toulon, France .
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    LiU, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Khranovskyy, Volodymyr
    Linköping University, Faculty of Science & Engineering. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Jonsson, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Low-temperature growth of polyethylene glycol-doped BiZn2VO6 nanocompounds with enhanced photoelectrochemical properties2017In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 5, no 3, p. 1112-1119Article in journal (Refereed)
    Abstract [en]

    We demonstrate scalable, low-cost and low-temperature (<100 °C) aqueous chemical growth of bismuth–zinc vanadate (BiZn2VO6) nanocompounds by BiVO4 growth on ZnO nanobelts (NBs). The nanocompounds were further doped with polyethylene glycol (PEG) to tune the electronic structure of the materials, as a means to lower the charge carrier recombination rate. The chemical composition, morphology, and detailed nanostructure of the BiZn2VO6 nanocompounds were characterized. They exhibit rice-like morphology, are highly dense on the substrate and possess a good crystalline quality. Photoelectrochemical characterization in 0.1 M lithium perchlorate in carbonate propylene shows that BiZn2VO6 nanocompounds are highly suitable as anodes for solar-driven photoelectrochemical applications, providing significantly better performance than with only ZnO NBs. This performance could be attributed to the heterogeneous catalysis effect at nanocompound and ZnO NB interfaces, which have enhanced the electron transfer process on the electrode surface. Furthermore, the charge collection efficiency could be significantly improved through PEG doping of nanocompounds. The photocurrent density of PEG-doped BiZn2VO6 nanocompounds reached values of 2 mA cm−2 at 1.23 V (vs. Ag/AgCl), over 60% larger than that of undoped BiZn2VO6 nanocompounds. Photoluminescence emission experiments confirmed that PEG plays a crucial role in lowering the charge carrier recombination rate. The presented BiZn2VO6 nanocompounds are shown to provide highly competitive performance compared with other state-of-the art photoelectrodes.

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  • 229. Order onlineBuy this publication >>
    Elsharif Zainelabdin, Ahmed ELtahir
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Lighting and Sensing Applications of Nanostructured ZnO, CuO and Their Composites2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Low dimensional nanostructures of zinc oxide (ZnO), cupric oxide (CuO), and their composite nanostructures possess remarkable physical and chemical properties. Fundamental understanding and manipulation of these unique properties are crucial for all potential applications. Integration of nanostructured ZnO and CuO and their hybrid composites may play a significant role in the existing technology while paving the way for new exciting areas. Solution based low temperature synthesis of ZnO and CuO nanostructures have attracted extensive research efforts during the last decade. These efforts resulted in a plenteous number of nanostructures ranging from quantum dots into very complex three dimensional nanomaterials. Among the various low temperature synthesis methods the hydrothermal technique became one of the most popular approaches. The use of hydrothermal approach enabled the synthesis of diversity of nanomaterials on conventional and nonconventional substrates such as metals, glass, plastic and paper etc.

    The primary objectives of this thesis are to study and understand the characteristics of nanostructured ZnO, CuO, and their hybrid composites synthesized at low temperature. Likewise, the hybrid composites were successfully utilized to fabricate light emitting diodes and sensors. This thesis is organized into three major parts. In the beginning the synthesis and characterization of nanostructured ZnO, CuO, and their composite nanostructures are elaborated. Efforts have been made to understand the selective assembly of hierarchical CuO nanostructures on ZnO nanorods and to correlate it to the observed unique properties of the CuO/ZnO composite nanostructures. In the second part of the thesis fabrication, characterization, and device application of ZnO/p-polymer hybrid light emitting diode (HyLEDs) on flexible substrates are presented. In particular single and blended p-type light emissive polymers were controllably developed for potential greener and cheaper white light emitters. It was found that the HyLEDs exhibited rectifying diode characteristics together with white light emission covering the entire visible range. In the third part, pH and relative humidity sensing applications of CuO nanoflowers, and CuO/ZnO nanocorals, respectively, are described. A pH sensor based on CuO nanoflowers demonstrated good sensitivity and reproducibility over a wide range of pH. By taking the advantages of the selective growth of CuO nanostructures on ZnO nanorods and their naturally formed p-n heterojunction the realization of high sensitivity humidity sensor was achieved. The humidity sensor fabricated from the CuO/ZnO nanocorals displayed the highest sensitivity factor reported so far for its constituent materials; along with reasonably fast dynamic responses. A brief outlook into future challenges and opportunities are also presented in the last part of the thesis. 

    List of papers
    1. Deposition of Well-Aligned ZnO Nanorods at 50 degrees C on Metal, Semiconducting Polymer, and Copper Oxides Substrates and Their Structural and Optical Properties
    Open this publication in new window or tab >>Deposition of Well-Aligned ZnO Nanorods at 50 degrees C on Metal, Semiconducting Polymer, and Copper Oxides Substrates and Their Structural and Optical Properties
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    2010 (English)In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 10, no 7, p. 3250-3256Article in journal (Refereed) Published
    Abstract [en]

    A two-step chemical bath deposition was utilized to synthesize ZnO nanorod arrays (ZNRAs) on metals, poly(3,4-ethylenedioxythiophene)/poly(strenesulfonate) (PEDOT/PSS) coated flexible plastic foils, and copper oxides coated glass substrates. The whole synthesis procedure was carried out at a low temperature of 50 degrees C, without any other substrate treatments. The low growth temperature showed improved influence on both the ZNRAs structural and optical properties. Scanning electron microscopy (SEM) images revealed well-aligned ZNRAs with large aspect ratios, and X-ray diffraction (X RI)) analysis indicated that single crystalline ZNRAs were achieved with high c-axial orientation tendency. Room temperature photoluminescence (PL) measurements demonstrated excellent optical properties of the as-grown ZNRAs with very low defect concentration contrary to what was believed to be achieved when lowering the growth temperature. The impact of the low deposition temperature on the ZNRAs structure is discussed in connection to the thermodynamics constraints, while the temperature effect on the defects formation and density in the as-deposited ZNRAs is elaborated and compared with recent theoretical calculations that appeared in the literature.

    Place, publisher, year, edition, pages
    The American Chemical Society, 2010
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-58270 (URN)10.1021/cg100390x (DOI)000279422700059 ()
    Available from: 2010-08-10 Created: 2010-08-09 Last updated: 2017-12-12
    2. CuO/ZnO Nanocorals synthesis via hydrothermal technique: growth mechanism and their application as Humidity Sensor
    Open this publication in new window or tab >>CuO/ZnO Nanocorals synthesis via hydrothermal technique: growth mechanism and their application as Humidity Sensor
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    2012 (English)In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 22, no 23, p. 11583-11590Article in journal (Refereed) Published
    Abstract [en]

    We demonstrate hydrothermal synthesis of coral-like CuO nanostructures by selective growth on ZnO nanorods (NR) at low temperatures. During the hydrothermal processing the resultant hydroxylated and eroded surface of ZnO NR becomes favorable for the CuO nanostructures growth via oriented attachments. Heterojunction p-n diodes fabricated from the CuO/ZnO nanocorals (NC) reveal stable and high rectification diode properties with a turn-on voltage ~1.52 V and negligible reverse current. The humidity sensing characteristics of the CuO/ZnO NC diodes exhibit a remarkable linear (in a semilogarithmic scale) decrease in the DC resistance by more than three orders when the relative humidity is changed from 30 – 90 %. The NC humidity sensor is also found to reveal the highest sensitivity factor ~6045 among available data for the constituent material’s and a response and recovery time of 6 s and 7 s, respectively.

    Place, publisher, year, edition, pages
    Royal Society of Chemistry, 2012
    Keywords
    Zinc oxide nanorods, copper oxide nanostructures, nanocorals, relative humidity, sensitivity factor
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-76676 (URN)10.1039/c2jm16597j (DOI)000304351400026 ()
    Note
    funding agencies|Swedish government||Available from: 2012-04-16 Created: 2012-04-16 Last updated: 2017-12-07Bibliographically approved
    3. Optical and current transport properties of CuO/ZnO nanocoral p-n heterostructure hydrothermally synthesized at low temperature
    Open this publication in new window or tab >>Optical and current transport properties of CuO/ZnO nanocoral p-n heterostructure hydrothermally synthesized at low temperature
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    2012 (English)In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 108, no 4, p. 921-928Article in journal (Refereed) Published
    Abstract [en]

    We demonstrate the synthesis and investigate the electrical and optical characteristics of nanocorals (NCs) composed of CuO/ZnO grown at low temperature through the hydrothermal approach. High-density CuO nanostructures (NSs) were selectively grown on ZnO nanorods (NRs). The synthesized NCs were used to fabricate p-n heterojunctions that were investigated by the current density-voltage (J-V) and the capacitance-voltage (C-V) techniques. It was found that the NC heterojunctions exhibit a well-defined diode behavior with a threshold voltage of about 1.52 V and relatively high rectification factor of similar to 760. The detailed forward J-V characteristics revealed that the current transport is controlled by an ohmic behavior for V andlt;= 0.15 V, whereas at moderate voltages 1.46 andlt;= V andlt; 1.5 the current follows a J alpha exp(beta V) relationship. At higher voltages (andgt;= 1.5 V) the current follows the relation J alpha V-2, indicating that the space-charge-limited current mechanism is the dominant current transport. The C-V measurement indicated that the NC diode has an abrupt junction. The grown CuO/ZnO NCs exhibited a broad light absorption range that is covering the UV and the entire visible parts of the spectrum.

    Place, publisher, year, edition, pages
    Springer Verlag (Germany), 2012
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-81220 (URN)10.1007/s00339-012-6995-2 (DOI)000307332800022 ()
    Available from: 2012-09-10 Created: 2012-09-10 Last updated: 2017-12-07
    4. Effect of the polymer emission on the electroluminescence characteristics of n-ZnO nanorods/p-polymer hybrid light emitting diode
    Open this publication in new window or tab >>Effect of the polymer emission on the electroluminescence characteristics of n-ZnO nanorods/p-polymer hybrid light emitting diode
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    2011 (English)In: Applied Physics A: Materials Science & Processing, ISSN 0947-8396, E-ISSN 1432-0630, Vol. 104, no 4, p. 1203-1209Article in journal (Refereed) Published
    Abstract [en]

    Hybrid light emitting diodes (LEDs) based on zinc oxide (ZnO) nanorods and polymers (single and blended) were fabricated and characterized. The ZnO nanorods were grown by the chemical bath deposition method at 50A degrees C. Three different LEDs, with blue emitting, orange-red emitting or their blended polymer together with ZnO nanorods, were fabricated and studied. The current-voltage characteristics show good diode behavior with an ideality factor in the range of 2.1 to 2.27 for all three devices. The electroluminescence spectrum (EL) of the blended device has an emission range from 450 nm to 750 nm, due to the intermixing of the blue emission generated by poly(9,9-dioctylfluorene) denoted as PFO with orange-red emission produced by poly(2-methoxy-5(20-ethyl-hexyloxy)-1,4-phenylenevinylene) 1,4-phenylenevinylene) symbolized as MEH PPV combined with the deep-band emission (DBE) of the ZnO nanorods, i.e. it covers the whole visible region and is manifested as white light. The CIE color coordinates showed bluish, orange-red and white emission from the PFO, MEH PPV and blended LEDs with ZnO nanorods, respectively. These results indicate that the choice of the polymer with proper concentration is critical to the emitted color in ZnO nanorods/p-organic polymer LEDs and careful design should be considered to obtain intrinsic white light sources.

    Place, publisher, year, edition, pages
    Springer Verlag (Germany), 2011
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-70328 (URN)10.1007/s00339-011-6411-3 (DOI)000293972100029 ()
    Available from: 2011-09-02 Created: 2011-09-02 Last updated: 2017-12-08
    5. Influence of the polymer concentration on the electroluminescence of ZnO nanorod/polymer hybrid light emitting diodes
    Open this publication in new window or tab >>Influence of the polymer concentration on the electroluminescence of ZnO nanorod/polymer hybrid light emitting diodes
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    2012 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 112, no 6, p. 064324-Article in journal (Refereed) Published
    Abstract [en]

    The effects of the polymer concentration on the performance of hybrid light emitting diodes (LEDs) based on zinc oxide nanorods (ZnO NRs) and poly(9,9-dioctylfluorene) (PFO) was investigated. Various characterization techniques were applied to study the performance of the PFO/ZnO NR hybrid LEDs fabricated with various PFO concentrations. The fabricated hybrid LEDs demonstrated stable rectifying diode behavior, and it was observed that the turn-on voltage of the LEDs is concentration dependent. The measured room temperature electroluminescence (EL) showed that the PFO concentration plays a critical role in the emission spectra of the hybrid LEDs. At lower PFO concentrations of 2-6 mg/ml, the EL spectra are dominated by blue emission. However, by increasing the concentration to more than 8 mg/ml, the blue emission was completely suppressed while the green emission was dominant. This EL behavior was explained by a double trap system of excitons that were trapped in the β-phase and/or in the fluorenone defects in the PFO side. The effects of current injection on the hybrid LEDs and on the EL emission were also investigated. Under a high injection current, a new blue peak was observed in the EL spectrum, which was correlated to the creation of a new chemical species on the PFO chain. The green emission peak was also enhanced with increasing injection current because of the fluorenone defects. These results indicate that the emission spectra of the hybrid LEDs can be tuned by using different polymer concentrations and by varying the current injected into the device.

    Place, publisher, year, edition, pages
    American Institute of Physics (AIP), 2012
    Keywords
    Hybrid light emitting diodes, ZnO nanorods, PFO, electroluminescence
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-81426 (URN)10.1063/1.4754542 (DOI)000309423200142 ()
    Available from: 2012-09-14 Created: 2012-09-14 Last updated: 2017-12-07Bibliographically approved
    6. CuO nanoflowers as an electrochemical pH sensor and the effect of pH on the growth
    Open this publication in new window or tab >>CuO nanoflowers as an electrochemical pH sensor and the effect of pH on the growth
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    2011 (English)In: JOURNAL OF ELECTROANALYTICAL CHEMISTRY, ISSN 1572-6657, Vol. 662, no 2, p. 421-425Article in journal (Refereed) Published
    Abstract [en]

    Well-crystallized flower-shaped cupric oxide (CuO) nanostructures composed of thin leaves have been synthesized by simple low-temperature chemical bath method and used to fabricate pH sensor. We examined the effect of the pH on the growth of the CuO nanostructures, by changing the pH of the precursor solutions different morphologies of the CuO nanostructures were obtained. CuO nanoflowers have recently become important as a material that provides an effective surface for electrochemical activities with enhanced sensing characteristics. The proposed sensor exhibited a linear electrochemical response within a wide pH range of (2-11). The experimental results (time response, electrochemical activity, reproducibility, absorption spectra, and XRD) indicate that the CuO nanoflowers can be used in pH sensor applications with enhanced properties.

    Place, publisher, year, edition, pages
    Elsevier, 2011
    Keywords
    CuO nanoflower; Morphological effect; Electrochemical; pH sensor; Repeatability
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-73334 (URN)10.1016/j.jelechem.2011.09.015 (DOI)000297881200020 ()
    Available from: 2012-01-03 Created: 2012-01-02 Last updated: 2014-01-15
    7. Synthesis and Characterization of CuO/ZnO Composite Nanostructures: Precursor’s Effects, and their Optical Properties
    Open this publication in new window or tab >>Synthesis and Characterization of CuO/ZnO Composite Nanostructures: Precursor’s Effects, and their Optical Properties
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    2012 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    A two steps hydrothermal method was developed to synthesize CuO/ZnO composite nanostructures (NSs) on glass substrate. The CuO NSs were selectively assembled on the lateral surface of ZnO nanorods (NRs) upon short growth duration. While the CuO NSs were entirely covered the surface of ZnO NRs at extended growth durations. The growth kinetics of CuO NSs is strongly dependent on the nature and the pH value of the precursor solution. When a single precursor solution of copper nitrate was applied in the synthesis process, a coral-like CuO/ZnO NSs were obtained. However, by adding a pH controlling agent to the precursor solution significant increase in the size of the grown CuO NSs was observed. The results revealed that the grown CuO NSs were robustly adhered to ZnO NRs, however, no explicit epitaxial relationship was found. The ZnO NRs band to band and defects emissions ratio was decreased compared to that of pure ZnO NRs, suggesting that oxygen vacancies are the probable growth sites of CuO NSs. The CuO/ZnO composite NSs exhibited a broad light absorption covering the whole visible range compared to the constituent materials. The low growth temperatures along with the optical properties of CuO/ZnO suggest these composite NSs may carry great potentials in light harvesting, sensing and emitting applications.

    Keywords
    Hydrothermal, ZnO nanorods, CuO nanostructures, deep level defects, composite
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-81428 (URN)
    Available from: 2012-09-14 Created: 2012-09-14 Last updated: 2014-01-15Bibliographically approved
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    Lighting and Sensing Applications of Nanostructured ZnO, CuO and Their Composites
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  • 230.
    Elsharif Zainelabdin, Ahmed
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Amin, Gul
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Zaman, Siama
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Metal Oxide Nanostructures and White Light Emission2012In: Proceedings of SPIE, the International Society for Optical Engineering, ISSN 0277-786X, E-ISSN 1996-756X, Vol. 8263, no 82630NArticle in journal (Refereed)
    Abstract [en]

    We report on white light emission from zinc oxide nanostructures chemically grown on paper substrates. The effect of the growth solution pH on the morphology is discussed. The light emission form light emitting diodes based on ZnO nanorods/organic polymer hybrids on paper substrate is presented. Further copper oxide was grown on the walls of zinc oxide nanorods and the optical properties were investigated.

  • 231.
    Erdmann, Tim
    et al.
    Leibniz Institute Polymerforschung Dresden eV, Germany; Technical University of Dresden, Germany; Polyera Corp, IL 60077 USA.
    Fabiano, Simone
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering. Polyera Corp, IL 60077 USA.
    Milian-Medina, Begona
    University of Valencia, Spain; Ciudad University of Cantoblanco, Spain.
    Hanifi, David
    Stanford University, CA 94305 USA.
    Chen, Zhihua
    Polyera Corp, IL 60077 USA.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Gierschner, Johannes
    Ciudad University of Cantoblanco, Spain.
    Salleo, Alberto
    Stanford University, CA 94305 USA.
    Kiriy, Anton
    Leibniz Institute Polymerforschung Dresden eV, Germany; Technical University of Dresden, Germany.
    Voit, Brigitte
    Leibniz Institute Polymerforschung Dresden eV, Germany; Technical University of Dresden, Germany.
    Facchetti, Antonio
    Polyera Corp, IL 60077 USA; Northwestern University, IL 60208 USA; Northwestern University, IL 60208 USA.
    Naphthalenediimide Polymers with Finely Tuned In-Chain pi-Conjugation: Electronic Structure, Film Microstructure, and Charge Transport Properties2016In: ADVANCED MATERIALS, ISSN 0935-9648, Vol. 28, no 41, p. 9169-+Article in journal (Refereed)
    Abstract [en]

    Naphthalenediimide-based random copolymers (PNDI-TVTx) with different p-conjugated dithienylvinylene (TVT) versus p-nonconjugated dithienylethane (TET) unit ratios (x = 100 -amp;gt; 0%) are investigated. The PNDI-TVTx-transistor electron/hole mobilities are affected differently, a result rationalized by molecular orbital topologies and energies, with hole mobility vanishing but electron mobility decreasing only by approximate to 2.5 times when going from x = 100% to 40%.

  • 232.
    Fabiano, Simone
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Abdollahi Sani, Negar
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering. RISE Acreo, Sweden.
    Kawahara, Jun
    RISE Acreo, Sweden; LINTEC Corp, Japan.
    Kergoat, Loig
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering. Aix Marseille University, France.
    Nissa, Josefin
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Engquist, Isak
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Ferroelectric polarization induces electronic nonlinearity in ion-doped conducting polymers2017In: Science Advances, ISSN 0036-8156, E-ISSN 2375-2548, Vol. 3, no 6, article id e1700345Article in journal (Refereed)
    Abstract [en]

    Poly(3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT:PSS) is an organic mixed ion-electron conducting polymer. The PEDOT phase transports holes and is redox-active, whereas the PSS phase transports ions. When PEDOT is redox-switched between its semiconducting and conducting state, the electronic and optical properties of its bulk are controlled. Therefore, it is appealing to use this transition in electrochemical devices and to integrate those into large-scale circuits, such as display or memory matrices. Addressability and memory functionality of individual devices, within these matrices, are typically achieved by nonlinear current-voltage characteristics and bistability-functions that can potentially be offered by the semiconductor-conductor transition of redox polymers. However, low conductivity of the semiconducting state and poor bistability, due to self-discharge, make fast operation and memory retention impossible. We report that a ferroelectric polymer layer, coated along the counter electrode, can control the redox state of PEDOT. The polarization switching characteristics of the ferroelectric polymer, which take place as the coercive field is overcome, introduce desired nonlinearity and bistability in devices that maintain PEDOT in its highly conducting and fast-operating regime. Memory functionality and addressability are demonstrated in ferro-electrochromic display pixels and ferro-electrochemical transistors.

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    fulltext
  • 233.
    Fabiano, Simone
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Effect of Gate Electrode Work-Function on Source Charge Injection in Electrolyte-Gated Organic Field-Effect Transistors2014In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 24, no 5, p. 695-700Article in journal (Refereed)
    Abstract [en]

    Systematic investigation of the contact resistance in electrolyte-gated organic field-effect transistors (OFETs) demonstrates a dependence of source charge injection versus gate electrode work function. This analysis reveals contact-limitations at the source metal-semiconductor interface and shows that the contact resistance increases as low work function metals are used as the gate electrode. These findings are attributed to the establishment of a built-in potential that is high enough to prevent the Fermi-level pinning at the metal-organic interface. This results in an unfavorable energetic alignment of the source electrode with the valence band of the organic semiconductor. Since the operating voltage in the electrolyte-gated devices is on the same order as the variation of the work functions, it is possible to tune the contact resistance over more than one order of magnitude by varying the gate metal.

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  • 234.
    Fabiano, Simone
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Weverberghs, Eric
    University of Mons-UMONS, Belgium.
    Gerbaux, Pascal
    University of Mons-UMONS, Belgium.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Poly(ethylene imine) impurities induce n-doping reaction in organic (semi)conductors2014In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 26, no 34, p. 6000-6006Article in journal (Refereed)
    Abstract [en]

    Volatile impurities contained in polyethyleneimine (PEI), and identified as ethyleneimine dimers and trimers, are reported. These N-based molecules show a strong reducing character, as demonstrated by the change in electrical conductivity of organic (semi) conductors exposed to the PEI vapor. The results prove that electron transfer rather than a dipole effect at the electrode interface is the origin of the work-function modification by the PEI-based layers.

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  • 235.
    Fabiano, Simone
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Ferroelectric Polarization Induces Electric Double Layer Bistability in Electrolyte-Gated Field-Effect Transistors2014In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 6, no 1, p. 438-442Article in journal (Refereed)
    Abstract [en]

    The dense surface charges expressed by a ferroelectric polymeric thin film induce ion displacement within a polyelectrolyte layer and vice versa. This is because the density of dipoles along the surface of the ferroelectric thin film and its polarization switching time matches that of the (Helmholtz) electric double layers formed at the ferroelectric/polyelectrolyte and polyelectrolyte/semiconductor interfaces. This combination of materials allows for introducing hysteresis effects in the capacitance of an electric double layer capacitor. The latter is advantageously used to control the charge accumulation in the semiconductor channel of an organic field-effect transistor. The resulting memory transistors can be written at a gate voltage of around 7 V and read out at a drain voltage as low as 50 mV. The technological implication of this large. difference between write and read-out voltages lies in the non-destructive reading of this ferroelectric memory.

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  • 236.
    Fabiano, Simone
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Usta, Hakan
    Polyera Corp, IL 60077 USA; Abdullah Gul University, Turkey.
    Forchheimer, Robert
    Linköping University, Department of Electrical Engineering, Information Coding. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Facchetti, Antonio
    Polyera Corp, IL 60077 USA.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Selective Remanent Ambipolar Charge Transport in Polymeric Field-Effect Transistors For High-Performance Logic Circuits Fabricated in Ambient2014In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 26, no 44, p. 7438-7443Article in journal (Refereed)
    Abstract [en]

    n/a

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  • 237.
    Faghani, Farshad
    Linköping University, Department of Science and Technology, Physics and Electronics.
    Thermal conductivity Measurement of PEDOT:PSS by 3-omega Technique2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Conducting polymers (CP) have received great attention in both academic and industrial areas in recent years. They exhibit unique characteristics (electrical conductivity, solution processability, light weight and flexibility) which make them promising candidates for being used in many electronic applications. Recently, there is a renewed interest to consider those materials for thermoelectric generators that is for energy harvesting purposes. Therefore, it is of great importance to have in depth understanding of their thermal and electrical characteristics. In this diploma work, the thermal conductivity of PEDOT:PSS is investigated by applying 3-omega technique which is accounted for a transient method of measuring thermal conductivity and specific heat.

    To validate the measurement setup, two benchmark substrates with known properties are explored and the results for thermal conductivity are nicely in agreement with their actual values with a reasonable error percentage. All measurements are carried out inside a Cryogenic probe station with vacuum condition. Then a bulk scale of PEDOT:PSS with sufficient thickness is made and investigated. Although, it is a great challenge to make a thick layer of this polymer since it needs to be both solid state and has as smooth surface as possible for further gold deposition.

    The results display a thermal conductivity range between 0.20 and 0.25 (W.m-1.K-1) at room temperature which is a nice approximation of what has been reported so far. The discrepancy is mainly due to some uncertainty about the exact value of temperature coefficient of resistance (TCR) of the heater and also heat losses especially in case of heaters with larger surface area. Moreover, thermal conductivity of PEDOT:PSS is studied over a wide temperature band ranging from 223 - 373 K.

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  • 238.
    Faisal, Fahad
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Analysis of methods for EMF in-situ measurements of LTE base stations2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this thesis is to analyze two proposed methods for in-situ measurements of electromagnetic fields transmitted by LTE base stations. One of the methods is based on measurements of physical broadcast channel (PBCH) using basic spectrum analyzer, whereas the other method is based on measurements of the reference signal (RS) using a decoder. Both alternatives are proposed to be used for extrapolation to the maximum electromagnetic field exposure level at full base station traffic load. The analysis is conducted with respect to instrument requirements, accuracy and time requirements. Different instrument settings of the spectrum analyzer and their impact on the measurement results is analyzed and discussed.

    In this work around 70% cases from all the measurements; the spectrum analyzer method overestimate the electric field strength compared with the LTE decoder method. All spectrum analyzer based measurements conducted in the main beam of an antenna at distances of less than 100 m were within ± 20% compared with the decoder results. Measurement results obtained in a reflective environment show that both methods are affected by fading, but significant deviations between the two methods indicate that the spectrum analyzer method is more sensitive to frequency selective fading.

    Based on the results and experiences obtained in this work the following conclusions have been drawn:

    • In the main beam of an antenna and for distances from the antenna of less than 100 m the two methods agree within ± 20 %.
    • When conducting spectrum analyzer based measurements in reflective environments it is important to follow standardized guidelines in order to avoid underestimating results
    • The decoder based method is most suitable when assessing the electric fields within a specific cell, for example to determine the compliance boundary of an antenna, whereas the spectrum analyzer based method is more suitable for general assessment, e.g. measurements in environments such as offices or other areas where no specific antenna is considered and slight deviation is acceptable.
    • The max-hold time for the spectrum analyzer method currently recommended in the latest draft of EN 50492 can be reduced to 5 s.
  • 239.
    Fakhar-E-Alam, M.
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering. GC University, Pakistan.
    Kishwer, Sultana
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Abbas, Najeeb
    GC University, Pakistan.
    Atif, M.
    King Saud University, Saudi Arabia; National Institute Laser and Optron, Pakistan.
    Nour, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Amin, Nasir
    GC University, Pakistan.
    Farooq, W. A.
    King Saud University, Saudi Arabia.
    Anticancer effects of nanometallic oxides and their ligands with photosensitizers in osteosarcoma cells2015In: Journal of Optoelectronics and Advanced Materials, ISSN 1454-4164, E-ISSN 1841-7132, Vol. 17, no 11-12, p. 1808-1815Article in journal (Refereed)
    Abstract [en]

    We studied the cytotoxic effects in Osteosarcoma (U2OS) cells to different nanosized metallic oxides e.g. zinc oxide nanowires (ZnO-NRs), manganese di-oxide nanowires (MnO2 NWs), ferric oxide nanoparticles (Fe2O3 NPs) individually and their connplexed forms with photosensitizers photofrin (R), 5-Aminolevulinic acid (5-ALA), and protoporphyrin IX (Pp IX). Cellular toxicity was assayed by cellular morphology, reactive oxygen species (ROS) detection, MTT assay under ultraviolet (UV), visible light and laser exposed conditions. Prominent cell death with above cited nanomaterials in their complexed forms with Photosensitizer was observed in labeled U2OS cells. This cell death might be due to their synergetic effect via the release of singlet oxygen species in Osteosarcoma cells showing their anticancer-cell effects.

  • 240.
    Fakhar-e-Alam, M
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. Pakistan Institute of Engineering and Applied Sciences, Pakistan.
    Usman Ali, Syed
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. , NED University of Engineering and Technology, Pakistan.
    Hussain Ibupoto, Zafar
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Atif, M
    Pakistan Institute of Engineering and Applied Sciences, Pakistan;Physics and Astronomy Department, College of Science, King Saud University, Saudi Arabia.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Erratum: “Phototoxic effects of zinc oxide nanowires (ZnO NWs) complexed with 5-ALA in RD cell line” (Laser Physics 21, 2165 (2011))2012In: Laser physics, ISSN 1054-660X, E-ISSN 1555-6611, Vol. 22, no 2, p. 476-476Article in journal (Other academic)
    Abstract [en]

    n/a

  • 241.
    Fakhar-e-Alam, M
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad, Pakistan.
    Usman Ali, Syed
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. Department of Electronic Engineering, NED University of Engineering and Technology, Karachi, Pakistan.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Atif, M
    Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad, Pakistan; Physics and Astronomy Department, College of Science, King Saud University, Riyadh, Saudi Arabia.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Erratum: “Phototoxic Effects of Zinc Oxide Nanowires (ZnO NWs) Complexed with 5-ALA in RD Cell Line” (Laser Physics 21, 2165 (2011))2012In: Laser physics, ISSN 1054-660X, E-ISSN 1555-6611, Vol. 22, no 1, p. 338-338Article in journal (Other academic)
    Abstract [en]

    n/a

  • 242.
    Fakhar-e-Alam, Muhammad
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. GC University, Faisalabad, Pakistan .
    Kishwar, Sultana
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Photodynamic effects of zinc oxide nanowires in skin cancer and fibroblast2014In: Lasers in Medical Science, ISSN 0268-8921, E-ISSN 1435-604X, Vol. 29, no 3, p. 1189-1194Article in journal (Refereed)
    Abstract [en]

    Cytotoxic effects of zinc oxide (ZnO) nanomaterials, individual and conjugated with a photosensitizer (protoporphyrin IX), were studied in the presence and absence of ultraviolet light exposure (240 nm of light wavelength for a very short time exposure) in cell cultures of human normal and cancerous skin models. Zinc Oxide nanowires (ZnO NWs) were grown on the capillary tip and conjugated with protoporphyrin IX (PpIX). This coated tip was used as tool/pointer for intracellular drug delivery protocol in suggested normal as well as carcinogenic cellular models. After true delivery of optimal drug, the labelled biological model was irradiated with UV-A, which led to a loss of mitochondrial membrane potential, as tested by neutral red assay (NRA).

  • 243.
    Fakhar-e-Alam, Muhammad
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. Pakistan Institute of Engineering and Applied Sciences, Pakistan.
    Usman Ali, Syed
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology. , NED University of Engineering and Technology, Pakistan.
    Ibupoto, Zafar Hussain
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Khun, Kimleang
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Atif, M.
    King Saud University, Saudi Arabia; National Institute of Laser and Optronics, Pakistan.
    Kashif, Muhammad
    University Malaysia Perlis, Kangar, Malaysia.
    Kai Loong, Foo
    University Malaysia Perlis, Kangar, Malaysia.
    Hashim, Uda
    University Malaysia Perlis, Kangar, Malaysia.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Sensitivity of A-549 human lung cancer cells to nanoporous zinc oxide conjugated with Photofrin2012In: Lasers in Medical Science, ISSN 0268-8921, E-ISSN 1435-604X, Vol. 27, no 3, p. 607-614Article in journal (Refereed)
    Abstract [en]

    In the present study, we demonstrated the use of nanoporous zinc oxide (ZnO NPs) in photodynamic therapy. The ZnO NPs structure possesses a high surface to volume ratio due to its porosity and ZnO NPs can be used as an efficient photosensitizer carrier system. We were able to grow ZnO NPs on the tip of borosilicate glass capillaries (0.5 mu m diameter) and conjugated this with Photofrin for efficient intracellular drug delivery. The ZnO NPs on the capillary tip could be excited intracellularly with 240 nm UV light, and the resultant 625 nm red light emitted in the presence of Photofrin activated a chemical reaction that produced reactive oxygen species (ROS). The procedure was tested in A-549 cells and led to cell death within a few minutes. The morphological changes in necrosed cells were examined by microscopy. The viability of control and treated A-549 cells with the optimum dose of UV/visible light was assessed using the MTT assay, and ROS were detected using a fluorescence microscopy procedure.

  • 244.
    Fakhar-E-Alam, Muhammad
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering. University of Elect Science and Technology China, Peoples R China; GC University, Pakistan.
    Waseem Akram, M.
    University of Elect Science and Technology China, Peoples R China.
    Iqbal, Seemab
    GC University, Pakistan.
    Alimgeer, K. S.
    COMSATS Institute Informat Technology, Pakistan.
    Atif, M.
    King Saud University, Saudi Arabia; National Institute Laser and Optron, Pakistan.
    Sultana, Kishwar
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Wang, Zhiming M.
    University of Elect Science and Technology China, Peoples R China.
    Empirical Modeling of Physiochemical Immune Response of Multilayer Zinc Oxide Nanomaterials under UV Exposure to Melanoma and Foreskin Fibroblasts2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 46603Article in journal (Refereed)
    Abstract [en]

    Carcinogenesis is a complex molecular process starting with genetic and epigenetic alterations, mutation stimulation, and DNA modification, which leads to proteomic adaptation ending with an uncontrolled proliferation mechanism. The current research focused on the empirical modelling of the physiological response of human melanoma cells (FM55P) and human foreskin fibroblasts cells (AG01518) to the multilayer zinc oxide (ZnO) nanomaterials under UV-A exposure. To validate this experimental scheme, multilayer ZnO nanomaterials were grown on a femtotip silver capillary and conjugated with protoporphyrin IX (PpIX). Furthermore, PpIX-conjugated ZnO nanomaterials grown on the probe were inserted into human melanoma (FM55P) and foreskin fibroblasts cells (AG01518) under UV-A light exposure. Interestingly, significant cell necrosis was observed because of a loss in mitochondrial membrane potential just after insertion of the femtotip tool. Intense reactive oxygen species (ROS) fluorescence was observed after exposure to the ZnO NWs conjugated with PpIX femtotip model under UV exposure. Results were verified by applying several experimental techniques, e.g., ROS detection, MTT assay, and fluorescence spectroscopy. The present work reports experimental modelling of cell necrosis in normal human skin as well as a cancerous tissue. These obtained results pave the way for a more rational strategy for biomedical and clinical applications.

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  • 245.
    Fali, Alireza
    et al.
    Univ Georgia, GA 30602 USA.
    Gamage, Sampath
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Howard, Marquez
    Univ Georgia, GA 30602 USA.
    Bolotin, Kirill
    Free Univ Berlin, Germany.
    Abate, Yohannes
    Univ Georgia, GA 30602 USA.
    Nanoimaging and Nano-FTIR of Muscovite Mica2018In: 2018 IEEE RESEARCH AND APPLICATIONS OF PHOTONICS IN DEFENSE CONFERENCE (RAPID), IEEE , 2018, p. 361-361Conference paper (Refereed)
    Abstract [en]

    n/a

  • 246.
    Faltpihl, Peter
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Ultrasonic sensing design and implementation for detecting and interacting with human beings in an AI system2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis covers the work performed to implement a Sonar sensor solution to detect human beings on a robotic lamp. A previously available solution was evaluated, but had to be redesigned due to faulty electronics. New hardware was developed, together with software to control this hardware. A software implementation of this new Sonar sensor system was also developed, on the robotic lamp itself.

    The nature of this thesis was very practical, so this report will focus on describing the different design stages that were performed, together with a wide discussion about future improvements and work, in order to achieve a robotic lamp that interacts with a human in an interesting manner.

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  • 247.
    Faxälv, Lars
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Bolin, Maria
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Jager, Edwin
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Lindahl, Tomas
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Chemistry.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Electronic control of platelet adhesion using conducting polymer microarrays2014In: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 14, no 16, p. 3043-3049Article in journal (Refereed)
    Abstract [en]

    We hereby report a method to fabricate addressable micropatterns of e-surfaces based on the conducting polymer poly(3,4-ethylenedioxythiophene) doped with the anion tosylate (PEDOT:Tos) to gain dynamic control over the spatial distribution of platelets in vitro. With thin film processing and microfabrication techniques, patterns down to 10 mu m were produced to enable active regulation of platelet adhesion at high spatial resolution. Upon electronic addressing, both reduced and oxidized surfaces were created within the same device. This surface modulation dictates the conformation and/or orientation, rather than the concentration, of surface proteins, thus indirectly regulating the adhesion of platelets. The reduced electrode supported platelet adhesion, whereas the oxidized counterpart inhibited adhesion. PEDOT:Tos electrode fabrication is compatible with most of the classical patterning techniques used in printing as well as in the electronics industry. The first types of tools promise ultra-low-cost production of low-resolution (greater than30 mu m) electrode patterns that may combine with traditional substrates and dishes used in a classical analysis setup. Platelets play a pronounced role in cardiovascular diseases and have become an important drug target in order to prevent thrombosis. This clinical path has in turn generated a need for platelet function tests to monitor and assess platelet drug efficacy. The spatial control of platelet adherence presented here could prove valuable for blood cell separation or biosensor microarrays, e.g. in diagnostic applications where platelet function is evaluated.

  • 248.
    Ferreira da Silva, Antonio
    et al.
    Instituto de Física, Universidade Federal da Bahia, Ondina, Salvador-Ba, Brazil .
    Castro Meira, M.V.
    CETEC-Universidade Federal do Recôncavo da Bahia, Cruz das Almas-Ba, Brazil and Instituto de Física, Universidade Federal da Bahia, Ondina, Salvador-Ba, Brazil.
    Persson, Clas
    Department of Materials Science and Engineering, Royal Institute of Technology, Stockholm, Sweden.
    Gutman, Nadav
    Racah Institute of Physics and the Center for Nanoscience and Nanotechnology, the Hebrew University of Jerusalem, Jerusalem, Israel.
    Sa’ar, Amir
    Racah Institute of Physics and the Center for Nanoscience and Nanotechnology, the Hebrew University of Jerusalem, Jerusalem, Israel.
    Klason, Peter
    Department of Physics, Göteborg University, Göteborg, Sweden.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Growth, Optical Characterization and Modelling of ZnO Nanorods on Si, SiC and Macroporous Si Structure2009In: Nanotech 2009 Vol. 3Nanotechnology 2009: Biofuels, Renewable Energy, Coatings, Fluidics and Compact Modeling: Technical proceedings of the 2009 NSTI Nanotechnology Conference and Expo, May 3-7, 2009, George R. Brown Convention Center, Houston, Texas, U.S.A, Austin, TX, USA: Nano Science and Technology Institute , 2009, p. 206-209Conference paper (Other academic)
    Abstract [en]

    Zinc Oxide (ZnO) and 4H-SiC are prominent materials with large applicability such as optoelectronic nanodevices and for instance ultraviolet detectors. There is lack of more information about optical transitions beyond the indirect band gap energy (BGE) of 4H-SiC and even more for ZnO direct BGE grown on the former material. Using the vapor-liquid-solid and the aqueous chemical growth methods we have grown ZnO nanorods on different substrates, such as quartz, n- and p-type silicon porous silicon and n-type 4H-SiC. The Scanning electron microscopy (SEM) are shown and compared for all samples. We have calculated the absorption and energy gap by employing a first-principle and a full-potential linearized augmented plane-wave (FPLAPW) method within the local density approximation (LDA). The absorption of ZnO nanorods, on different substrates, is lower than that of quartz substrate when photon energy is low. It is shown the strong effect of 4H-SiC on ZnO nanorods. Experiment and theory show a good aggreement when the optical energy gap is considered for both materials.

  • 249.
    Fornander, Gustaf
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Konstruktion av nätstation2012Independent thesis Basic level (university diploma), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Denna rapport behandlar ett examensarbete utfört av Gustaf Fornander våren 2012. Där uppgiften som låg till grund för examensarbetet var behov av en konstruktör för elkonstruktion av en nätstation på Scania i Oskarshamn. Uppgifterna blev att ta fram arbetsritningar, apparatlistor och reläskyddsinställningar. Projektet som drevs som en totalentreprenad av Sydsvenska Elanläggningar resulterade i en komplett nätstation med högspänningsställverk, transformator och lågspänningsställverk.

  • 250.