Yazar "Ongul, Fatih" seçeneğine göre listele

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    Effect of UV exposure of ITO/PEDOT:PSS substrates on the performance of inverted-type perovskite solar cells
    (Springer, 2020) Alishah, Hamed Moeini; Kazici, Mehmet; Ongul, Fatih; Bozar, Sinem; Rodop, Macide Canturk; Kahveci, Cihangir; Arvas, Melih Besir
    We have fabricated inverted-type perovskite solar cells employing CH3NH3PbI3-xClx perovskite in the form of ITO/PEDOT:PSS/Perovskite/PCBM/Al. The effects of UV radiation on ITO/PEDOT:PSS substrates have been investigated for perovskite solar cells. ITO/PEDOT:PSS substrates were exposed to UV radiation for 5 to 15 min. The perovskite solar cells fabricated on UV-irradiated ITO/PEDOT:PSS substrates exhibited better performance as compared to those fabricated on substrates employing non-treated PEDOT:PSS. We used photovoltaic characterization, UV-VIS absorption, sheet resistance, X-ray diffraction (XRD), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), and external quantum efficiency (EQE) characterization techniques to investigate the effect of UV irradiation of ITO/PEDOT:PSS substrates on the performance of perovskite solar cells. The devices fabricated on ITO/PEDOT:PSS (UV irradiated for 10 min) exhibited the best device performance of all. We achieved a 9% increase in the overall power conversion efficiency for the devices fabricated on substrates exposed to UV radiation.
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    Effects of different formulation PEDOT:PSS hole transport layers on photovoltaic performance of organic solar cells
    (John Wiley and Sons, August 2017) Ongul, Fatih; Yuksel, Sureyya Aydin; Kazici, Mehmet; Bozar, Sinem; Gunbatti, Anil; Gunes, Serap
    In this study, the effects of the various types of PEDOT:PSS with different conductivities on the photovoltaic parameters of organic solar cells were investigated. The performances of five various commercially available PEDOT:PSS with formulations such as FET, PT2, PH1000, PH500 and PH were compared. It was observed that the device employing PH1000 as an interlayer between ITO and the active layer exhibited the highest photovoltaic performance as compared to other devices with FET, PT2, PH500 and PH.
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    Influences of CdSe NCs on the photovoltaic parameters of BHJ organic solar cells
    (Pergamon-Elsevier Science Ltd, 2018) Ongul, Fatih; Yuksel, Sureyya Aydin; Allahverdi, Cagdas; Bozar, Sinem; Kazici, Mehmet; Gunes, Serap
    In this study, the high quality CdSe nanocrystals (NCs) capped with stearic acid were synthesized in a solvent and then purified four times by using the precipitation and redissolution process. The average size of the synthesized CdSe NCs was determined similar to 3.0 nm via transmission electron microscopy (TEM) measurement and their corresponding optical band edge energy was also calculated as similar to 2.1 eV using ultraviolet-visible (UV-Vis) absorption spectroscopy. The bulk heterojunction (BHJ) hybrid solar cells based on a ternary system including P3HT, PCBM and CdSe NCs at different weight concentrations (0 wt%, 0.1 wt%, 0.5 wt%, 1 wt% and 2 wt%) were fabricated by spin-casting process. The effect of the concentration of CdSe NCs on the photovoltaic parameters of these BHJ organic solar cells was investigated. The surface morphology of the photoactive layer modified by the incorporation of CdSe NCs into P3HT:PCBM matrix was observed with scanning electron microscopy (SEM). It was shown that when the concentration of CdSe NCs increases above 0.1 wt% in this ternary system, the photovoltaic performance of the devices significantly decreases. The power conversion efficiency of the organic photovoltaic (OPV) device was enhanced similar to 20% by incorporating CdSe NCs with 0.1 wt% with respect to those without CdSe NCs. (C) 2017 Elsevier B.V. All rights reserved.
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    Theoretical and experimental investigations of the 2-(4-chlorophenyl)-3-{[5-(2-cyano-2-phenylethenyl)]furan-2-yl}acrylonitrile molecule as a potential acceptor in organic solar cells
    (Iop Publishing Ltd, 2016) Kazici, Mehmet; Bozar, Sinem; Yuksel, Sureyya Aydin; Ongul, Fatih; Gokce, Halil; Gunes, Serap; Goreci, Cigdem Yorur
    A novel soluble asymmetric acrylonitrile derivative, 2-(4-Chlorophenyl)-3-{[5-(2-cyano-2-phenylethenyl)]furan-2-yl}acrylonitrile (CPCPFA, 3) was synthesized in three steps by Knoevenagel condensation. The structure of the CPCPFA was characterized using UV-vis, FTIR, H-1 NMR, C-13 NMR, and LC-MS. CPCPFA was evaluated as an electron acceptor in bulk heterojunction organic solar cells. Its optical and electronic properties as well as photovoltaic performance were investigated.