Temperature activated ionic conductivity in gallium and indium phthalocyanines

The effects of introducing gallium and indium metals into phthalocyanine molecules were investigated via temperature and frequency dependent dielectric spectroscopy. The dielectric properties of Ga(III) and In(III) phthalocyanine pellets were measured at frequencies from 1 kHz to 1 MHz in the temperature range 300–530 K. The temperature dependence of the real part of the dielectric constant suggested that these compounds exhibit semiconductor behavior. The activation energy values were calculated from the Arrhenius plots at different frequencies. A distinct transition in these plots indicated the activation of ionic conductivity at higher temperatures

PENTACENE-BASED ORGANIC THIN FILM TRANSISTOR WITH SiO2 GATE DIELECTRIC

An organic thin film transistor (OTFT) based on pentacene was fabricated with SiO2 as the gate dielectric material. We have investigated the effects of the thickness of pentacene layer and the organic semiconductor (OSC) material on OTFT devices at two different thicknesses. Au metal was deposited for gate, source and drain contacts of the device by using thermal evaporation method. Pentacene thin film layer was also prepared with thermal evaporation. Our study has shown that the change in pentacene thickness makes a noteworthy difference on the field effect mobility (mu(FET)), values, threshold voltages (V-T) and on/off current ratios (I-on/I-off). OTFTs exhibited saturation at the order of mu(FET) of 3.92 cm(2)/Vs and 0.86 cm(2)/Vs at different thicknesses. I-on/I-off and V-T are also thickness dependent. I-on/I-off is 1 x 10(3), 2 x 10(2) and V-T is 15 V, 27 V of 40 nm and 60 nm, respectively. The optimized thickness of the pentacene layer was found as 40 nm. The effect of the OSC layer thickness on the OTFT performance was found to be conspicuous

Manufacturing of inorganic-organic hybrid solar cells by screen printing method

In this study, hybrid bulk heterojunction (BHJ) organic solar cells with a poly(3-hexylthiophene-2,5- diyl)(P3HT):(6,6)-phenyl $C _{61}$ -butyric acid methyl ester (PC61 BM) active layer, a poly(3,4-ethylenedioxyt- hiophene)-poly(styrenesulfonate)(PEDOT:PSS) buffer layer, and an electrochemically deposited zinc oxide (ZnO) n-type inorganic layer were produced. The PET/ITO/ZnO/PEDOT:PSS/P3HT:PC61 BM/Al device was manufactured and tested under solar illumination (AM1.5G, 100 mW/$Cm^ 2$ )

PENTACENE-BASED ORGANIC THIN FILM TRANSISTOR WITH SiO2 GATE DIELECTRIC

WOS: 000354413700006An organic thin film transistor (OTFT) based on pentacene was fabricated with SiO2 as the gate dielectric material. We have investigated the effects of the thickness of pentacene layer and the organic semiconductor (OSC) material on OTFT devices at two different thicknesses. Au metal was deposited for gate, source and drain contacts of the device by using thermal evaporation method. Pentacene thin film layer was also prepared with thermal evaporation. Our study has shown that the change in pentacene thickness makes a noteworthy difference on the field effect mobility (mu(FET)), values, threshold voltages (V-T) and on/off current ratios (I-on/I-off). OTFTs exhibited saturation at the order of mu(FET) of 3.92 cm(2)/Vs and 0.86 cm(2)/Vs at different thicknesses. I-on/I-off and V-T are also thickness dependent. I-on/I-off is 1 x 10(3), 2 x 10(2) and V-T is 15 V, 27 V of 40 nm and 60 nm, respectively. The optimized thickness of the pentacene layer was found as 40 nm. The effect of the OSC layer thickness on the OTFT performance was found to be conspicuous.Sakarya University Research Project UnitSakarya University [2013-02-02-009]; Duzce University Research Project UnitDuzce University [2013.05.02.195]This work has been supported financially by Sakarya University Research Project Unit under project No. 2013-02-02-009, and Duzce University Research Project Unit under project No. 2013.05.02.195. Authors thank Prof. Salih Okur for his support with his facilities during Pentacene deposition

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

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

Effect of Intrinsic Polymer Properties on the Photo Sensitive Organic Field-effect Transistors (Photo-OFETs)

In this work, we have demonstrated how the intrinsic properties of a conjugated polymer can influence the electro-optical characteristics of photo sensitive organic field - effect transistors (Photo-OFETs). Photo-OFETs fabricated with three batches of poly[2-methoxy,5-(3′,7′- dimethyl-octyloxy)]-p-phenylene vinylene (MDMO-PPV) were investigated in the scope of our work. Photo-OFETs were fabricated with the polymers, than electrically and electrooptically characterized. It was observed that the channel current and the field-effect mobility increase with increasing polymer molecular weight. Interestingly, the electro-optical characteristics and photo switching properties of the transistors were found to depend on the polydispersity (PDI) of the polymer as well. These results are explained in terms of influences of chain packing, ordering and trap density on the FET switching properties and transistor parameters

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