Yazar "Kosemen, Arif" seçeneğine göre listele

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    Boosting inverted type organic solar cell efficiency through the use of spray coated Y and Sn co-doped zinc oxide nanoparticles as an electron transport layers
    (Springer, 2023) Gegin, Keziban; Demir, Ahmet; Ozturk, Sadullah; Erkovan, Mustafa; Kosemen, Arif
    The purpose of this study was to investigate the use of zinc oxide nanoparticles (ZnO NPs) as an electron transport layer (ETL) in inverted type organic solar cells (IOSCs). Three different forms of ZnO NPs were synthesized: undoped, doped with Sn or Y, and co-doped with combinations of these elements (Sn-co-doped Y). The ZnO NPs ETL was introduced into the solar cells using a spray coating technique, resulting in a bulk heterojunction structure of ZnO NPs/P3HT:PCBM/V2O5/Ag. Various methodological approaches were used to characterize the ZnO nanoparticles, including scanning electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, and ultraviolet/visible spectrophotometer. The current-voltage performance of the solar cells was measured under 100 mW/cm(2) white light. The results showed that the efficiency of the solar cells using undoped ZnO as ETL was 3.09%. However, the use of 0.5 wt% Sn and 1 wt% Y co-doped ZnO as ETL significantly improved the efficiency to 3.67%, representing an approximate increase of 19% compared to the undoped ETL. All experimental processes were performed under ambient air conditions. In conclusion, this study highlights the potential of using doped or co-doped ZnO NPs as ETL for fabricating IOSCs at low temperatures and improving their efficiency.
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    The novel n-channel liquid crystal organic field effect transistor (LC-n-OFET): A promising technology for low-power electronics
    (Elsevier, 2024) Kip, Sule Zeynep; Gegin, Keziban; Demir, Ahmet; Koysal, Oguz; Ozturk, Sadullah; Kosemen, Arif
    In this study, a novel n-channel liquid crystal organic field effect transistor (LC-n-OFET) was fabricated using a mixture of E7 nematic liquid crystal (NLC) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) in an OFET cell. The LC-n-OFET performance was investigated regarding dielectric properties, UV illumination sensitivity, and channel length dependence. Output and transfer current-voltage (I-V) characteristics were measured to evaluate the electrical properties in dark and under UV illumination for varying channel lengths. Additionally, the dielectric characteristics of the LC-n-OFET were determined along with the capacitance-frequency response (Ci-f), threshold voltage (VTh), field-effect mobility (mu FET), and on/off current ratio (Ion/off) as a function of UV illumination intensity and channel length changes. Electrical measurements showed the Ion/off current ratio is inversely proportional to channel length but directly proportional to UV intensity. Meanwhile, the threshold voltage (VTh) and mobility (mu FET) increased with longer channel length and higher light intensity. Overall, the novel LC-n-OFET exhibited promising performance with low VTh, high mu FET, and large Ion/off.