Fe doped TiO2 thin film as electron selective layer for inverted solar cells

WOS: 000377311400044Inverted P3HT:PCBM based organic solar cells were fabricated by using Fe2+ doped TiO2 films as electron selective layer. Pure and Fe2+ doped TiO2 films were prepared by sol gel method and the optical as well as the structural properties of the thin films were characterized by UV-Vis spectrophotometer and SEM. The concentration of Fe2+ was varied as 0.5%, 1%, 2% and 3% (w/w) in TiO2 layer and the influence of Fe2+ doping on the solar cell parameters were systemically investigated. Photocurrent density of the solar cells as increased from 8.75 to 13.8 mA/cm(2), whereas the solar cell efficiency changed from 1.7% to 2.79% by using Fe2+ doped TiO2 electron selective layer. It was experimentally found and demonstrated that charge injection and selection in the TiO2 interlayer was improved by doping of Fe2+ atoms in the TiO2. (C) 2016 Elsevier Ltd. All rights reserved.TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [113M935]This research is supported by TUBITAK Grant No.: 113M935

Performance enhancement of inverted type organic solar cells by using Eu doped TiO2 thin film

WOS: 000418617000010In the present work, europium (Eu) has been used as a dopant element in titanium dioxide (TiO2) crystal structure to enhance the photovoltaic performance of the inverted type organic solar cells fabricated with TiO2 thin film as an electron transport layer. Poly(3-hexylthiophene): phenylC61-butyric acid methyl ester (P3HT: PCBM) blend has been used as an active layer and Eu: TiO2 thin films have been fabricated with different Eu concentrations as 0, 1, 5, 7 and 10% (w/w) by sol-gel method. Effect of Eu doping concentration on the photovoltaic performance of the inverted type solar cells has been investigated. Inverted type organic solar cells using Eu doped TiO2 thin films as electron transport layer has been fabricated as a structure of ITO/Eu:TiO2/P3HT: PCBM/Ag. Power conversion efficiency of the fabricated solar cells increased from 1.16% to 2.47% at 5% Eu doping concentration. Electron transport and hole blocking properties of the TiO2 inter layer has been improved by Eu doping.Ahi Evran UniversityAhi Evran University [MMF.A3.16.009]This research is supported by Ahi Evran University Grant no.: MMF.A3.16.009

Electrochemical Growth of Pd Doped ZnO Nanorods

WOS: 000349827200059In this work, dense arrays of pure and Pd doped zinc oxide (ZnO) nanorods (NRs) were fabricated by an electrochemical growth. Pure and Pd doped ZnO NRs were characterized via scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and optic spectroscopy. Structural studies confirmed that pure and doped ZnO NRs present the hexagonal wurtzite crystal structures. The optical properties of pure and doped ZnO NRs were found to present redshift by increasing doping concentration. The diameters of the NRs increase with increasing Pd doping concentration under same condition. Compared with pure ZnO NRs, the Pd doped ZnO NRs presents improved optical properties in terms of bandgap energy from 3.24 eV to 1.97 eV. These bandgap values were obtained by optical absorption using a UV-Visible spectrophotometer. In addition, Pd doping concentration in ZnO affects the active species on the surface such as oxygen deficiencies and hydroxyls. The electrochemically growing mechanism is also discussed in detail in the scope of this work. (C) 2015 The Electrochemical Society. All rights reserved.TUBITAK [113F403, 113M935]The authors thank KUYTAM at Koc University and Dr. Baris Yagci for SEM measurements. This research is supported by TUBITAK grant no.: 113F403 and grant no.: 113M935

Comparison of Electronic Parameters of Low Voltage Organic Field-Effect Transistors with Novel Gel Gate Insulators

WOS: 000469369800012In this paper, regioregular poly(3-hexylthiophene-2,5-diyl) (rr-P3HT)-based low voltage organic field-effect transistors (OFETs) with three kinds of non-ionic gel gate insulators (NIGIs) were fabricated and compared in terms of their electronic properties. One of the NIGI was prepared by mixing solution-processed poly(methyl acrylate) (PMA) with propylene carbonate (PC) until it becoming a gel state and same procedure was applied to the solution-processed copolymers of PMA called as P18 and P28. As a result, it was seen that fabricated OFETs could be operated at low voltages which is very significant property in order to manipulate the devices in low power electronic applications. On the other hand, it was noted that mobilities of the transistors were enhanced by reducing the effective capacitance (EC) of the NIGIs. This could be attributed to less charge carrier self-localization formation between the insulator-semiconductor interface when the EC was decreased. Furthermore, devices showed similar on-to-off current (I-ON/I-OFF) ratio which was good for using them in inverter applications. Besides, subthreshold swing (SS) for the P18 non-ionic gel OFET (NIGOFET) was the highest probably due to the less water-repellent chemical structure of the P18 NIGI.Duzce University Scientific Research Projects unitDuzce University [2017.07.02.621, 2015.05.03.381]This study was presented in the 5th International Conference on Materials Science and Nanotechnology For Next Generation (MSNG2018) which held between 4-6 October 2018 in Cappadocia Turkey. Furthermore, we appreciate the Duzce University Scientific Research Projects unit for providing us financial support under the Grant [2017.07.02.621] and [2015.05.03.381]

Electrical conduction and NO2 gas sensing properties of ZnO nanorods

WOS: 000334293200013Thermally stimulated current (TSC), photoresponse and gas sensing properties of zinc oxide (ZnO) nanorods were investigated depending on heating rates, illumination and dark aging times with using sandwich type electrode system. Vertically aligned ZnO nanorods were grown on indium tin oxide (ITO) coated glass substrate by hydrothermal process. TSC measurements were performed at different heating rates under constant potential. Photoresponse and gas sensing properties were investigated in dry air ambient at 200 degrees C. For gas sensing measurements, ZnO nanorods were exposed to NO2 (100 ppb to 1 ppm) in dark and illuminated conditions and the resulting resistance transient was recorded. It was found from dark electrical measurements that the dependence of the dc conductivity on temperature followed Mott's variable range hopping (VRH) model. In addition, response time and recovery times of ZnO nanorods to NO2 gas decreased by exposing to white light. (C) 2014 Elsevier B. V. All rights reserved.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [111M261]This study was supported by Scientific and Technological Research Council of Turkey (TUBITAK) entitled "Development of Automotive Gas Sensors Based on Nano-Metal-Oxide Semiconductor with increased Selectivity, Sensitivity and Stability" (Project Number: 111M261)

Fabrication of 1D ZnO nanostructures on MEMS cantilever for VOC sensor application

WOS: 000339994900047This study reports the fabrication method and sensing performance for novel 1D zinc oxide (ZnO) nanorods and nanotubes grown on nickel MEMS cantilevers. The fabrication of the nanostructures and the cantilevers are simple and low-cost using standard lithography, electrodeposition, and hydrothermal etching processes. 1D ZnO nanostructures increase the total sensitive area for biological and chemical sensor applications. We performed experiments with various VOCs with a real-time sensor system developed in our laboratory. While Ni microcantilevers produced no signal, ZnO nanostructure coated microcantilevers showed good sensitivity and repeatable changes. Furthermore, the nanotube coated microcantilevers showed more than 10 fold increase in sensitivity compared to the nanorod coated microcantilevers which can be explained to the fact that ZnO nanotubes have higher surface area and subsurface oxygen vacancies and these provide a larger effective surface area with higher surface-to-volume ratio as compared to ZnO nanorods. The tests are performed using dynamic mode of operation near resonant frequency using magnetic actuation and optical sensing. The phase stability and the limit of detection of ZnO nanotube coated microcantilevers exposed to diethylamine (DEA) were 0.02 degrees and lower than 10 ppm, respectively. ZnO nanostructure coated microcantilevers have good potential for VOC sensor applications especially for amine groups. (C) 2014 Elsevier B.V. All rights reserved.TUBITAK-BIDEB National Postdoctoral Research Fellowship Program; TUBITAK [111E184, 113F403]Necmettin Kilinc was supported by TUBITAK-BIDEB National Postdoctoral Research Fellowship Program. The authors thank KUY-TAM and Dr. Bans Yagci for SEM measurements. This research is supported by TUBITAK Grant no.: 111E184 and 113F403

Preparation of Transparent Conductive Electrode via Layer-By-Layer Deposition of Silver Nanowires and Its Application in Organic Photovoltaic Device (vol 10, 46, 2020)

Basarir, Fevzihan/0000-0003-0055-7151;WOS:000526090400097[No Abstract Available]National Research Foundation (NRF) [NRF-2018K2A9A1A06066082]; Technology Development Program to Solve Climate Changes of the National Research Foundation (NRF) - Ministry of Science, ICT & Future Planning [NRF-2016M1A2A2940914]; TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [113M772]; Pukyong National University Research Fund in 2017 [CD-2017-1504]The first two authors contributed equally to this work. This research was supported by the National Research Foundation (NRF) (NRF-2018K2A9A1A06066082) and the Technology Development Program to Solve Climate Changes of the National Research Foundation (NRF) funded by the Ministry of Science, ICT & Future Planning (NRF-2016M1A2A2940914). The authors would like to acknowledge the financial support from TUBITAK (Grant No. 113M772). This work was also supported by the Pukyong National University Research Fund in 2017 (CD-2017-1504)

Use of side chain thiophene containing copolymer as a non-ionic gel-dielectric material for sandwich OFET assembly

The performances of non-ionic-gel-gated poly(3-hexylthiophene) [P3HT] transistors were investigated by using poly(methyl methacrylate) [PMMA] homopolymer and poly(3-methylthienyl methacrylate-co-methyl methacrylate) [P(MMA-co-MTM)] copolymer alternatively in the gel of a novel organic field effect transistors (OFETs) assembly. The results are quite remarkable and open a new approach to obtain high mobility and low operating voltage. This new fabrication process, namely the sandwich model with a non-ionic-gel-dielectric material has been improved by using a compatible copolymer [P(MMA-co-MTM)] in terms of chemical similarity at the interface of the active and dielectric layers. The gel material proposed, included side chain thiophene-based copolymer, has been found to enhance the mobility of the device for almost two times and decreases the working and threshold voltages slightly as well. (C) 2012 Elsevier B.V. All rights reserved

An efficient organic inverted solar cell with AnE-PVstat:PCBM active layer and V2O5/Al anode layer

WOS: 000330489900009An inverted organic solar cell, which is based on anthcene-containing poly (p-phenylene-ethynylene)-alt-poly(p-phenylene-vinylene) (PPE-PPV) polymer (AnE-PVstat) and phenyl C-61 butyric acid methyl ester (PCBM), was fabricated with Titanium dioxide (TiO2) electron transport layer and V2O5/Al anode layer. In this study, we have investigated the effect of V2O5 thickness on solar cell efficiency. Power conversion efficiency of 3.26% has been achieved for 15 nm V2O5 layer. The lifetime of the cell was investigated using ISOS-L-1. The test indicated that the durability of the solar cell, which is designed in ITO/TiO2/AnE-PVstat:PCBM/V2O5 (15 nm)/Al configuration, is 99% under standard solar irradiation of 100 mW/cm(2) (AM 1.5 G) at ambient conditions for 24 h. (C) 2013 Elsevier Ltd. All rights reserved

Preparation of Transparent Conductive Electrode via Layer-By-Layer Deposition of Silver Nanowires and Its Application in Organic Photovoltaic Device

Basarir, Fevzihan/0000-0003-0055-7151; Lee, Bo Ram/0000-0002-4670-6717; kosemen, arif/0000-0002-7572-7963WOS:000516825600046PubMed: 31878159Solution processed transparent conductive electrodes (TCEs) were fabricated via layer-by-layer (LBL) deposition of silver nanowires (AgNWs). First, the AgNWs were coated on (3-Mercaptopropyl)trimethoxysilane modified glass substrates. Then, multilayer AgNW films were obtained by using 1,3-propanedithiol as a linker via LBL deposition, which made it possible to control the optical transmittance and sheet resistance of multilayer thin films. Next, thermal annealing of AgNW films was performed in order to agent their electrical conductivity. AgNW monolayer films were characterized by UV-Vis spectrometer, field emission scanning electron microscopy, optical microscopy, atomic force microscopy and sheet resistance measurement by four-point probe method. The high performances were achieved with multilayer films, which provided sheet resistances of 9 Omega/sq, 11 Omega/sq with optical transmittances of 71%, 70% at 550 nm, which are comparable to commercial indium tin oxide (ITO) electrodes. Finally, an organic photovoltaic device was fabricated on the AgNW multilayer electrodes for demonstration purpose, which exhibited power conversion efficiency of 1.1%.National Research Foundation (NRF) [NRF-2018K2A9A1A06066082]; TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [113M772]; Pukyong National University Research Fund [CD-2017-1504]First two authors contributed equally to this work. This research was supported by the National Research Foundation (NRF) (NRF-2018K2A9A1A06066082). The authors would like to acknowledge the financial support from TUBITAK (Grant No: 113M772). This work was supported by the Pukyong National University Research Fund in 2017 (CD-2017-1504)