Yazar "Demiri, S." seçeneğine göre listele

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    Electrochromic NiO Thin Films Prepared by Spin Coating
    (Amer Inst Physics, 2017) Ozutok, F.; Demiri, S.; Ozbek, E.
    Recently, smart windows are very important because they are often being used in smart buildings and car glasses (windows). At this point, producing effective electrochromic materials is so necessary. In this study, we produced NiO thin films by using spin coating technique on In-doped SnO2 (ITO) substrate. Nickel proportions of these nickel oxide (NiO) films are 3, 5 and 7 %. Nickel acetate tetrahydrate is the initial solution and solvents are ethylene gl ycol and n-hexzane. Structural properties and surface images are investigated by using x-ray diffactometer (XRD) and scanning electron microscope (SEM) device, respectively. In addition, electrochemical behavior is investigated by cyclic voltammet. A correlation between surface morphology and electrochromic performance was observed as well.
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    Enhancing the Co gas sensing properties of ZnO thin films with the decoration of MWCNTs
    (Springer, 2019) Özütok, Fatma; Karaduman Er, Irmak; Acar, S.; Demiri, S.
    Multi-walled carbon nanotubes (MWCNTs) onto flower-like patterned ZnO seed layers were prepared by spin coating method. The etching of the MWCNTs was examined by HCl acid treatment. The effect of structural, morphological and elemental properties of the ZnO/MWCNTs were determined by XRD, SEM, and EDX, respectively. The gas sensing properties of ZnO seed layer and MWCNT/ZnO nanocomposites were studied as a function of operating temperature and gas concentration. The incorporation of MWCNT were given results such as reducing the operating temperature to 70 degrees C and enhancement in sensor response for 25ppm CO gas. It was obtained that the highest sensing response of 62% at 70 degrees C for raw-MWCNTs/ZnO sensor as compared to etched-MWCNT/ZnO and ZnO sensor which gave a sensing response of 19% and 21% at operating temperature of 70 degrees C and 150 degrees C, respectively. Results showed that the deposition of metal oxide sensors with MWCNT is a promising strategy for improvement of CO gas sensing properties.
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    Nanoflower-like ZnO films prepared by modified chemical bath deposition: Synthesis, optical properties and NO2 gas sensing mechanism
    (Inst Materials Physics, 2017) Özütok, F.; Demiri, S.
    In the present work, nanoflower-shape zinc oxide (ZnO) films synthesized by modified chemical bath deposition (CBD). The optimum working temperature and pH was determined 50±5 °C and 9.8, respectively. Conditioning solution can functioned as an adhesive in CBD process which have been used for the first time. The effect of annealing temperature (450, 500 and 550 °C) was studied and the changing structural, elemental and morphological properties were investigated by using XRD, EDX and SEM devices, respectively. All polycrystalline films had [002] preferential orientation and the maximum crystallization was observed in ZnO films that annealed at 500 °C. Detailed optical properties (absorption, band gap energy) were investigated by using Uv-Vis spectroscopy. Optical transmittance spectra showed high optical absorption below to 370 nm in the range 300-900 nm. Gas sensing mechanism for 0.5 ppm NO2 gas was investigated by using home-made gas sensing chamber that sensor working at 200 °C and nano-flower dimensions severly affected to gas sensitivities. © 2017, Inst Materials Physics. All rights reserved.
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    NANOFLOWER-LIKE ZnO FILMS PREPARED BY MODIFIED CHEMICAL BATH DEPOSITION: SYNTHESIS, OPTICAL PROPERTIES AND NO2 GAS SENSING MECHANISM
    (Inst Materials Physics, 2017) Ozutok, F.; Demiri, S.
    In the present work, nanoflower-shape zinc oxide (ZnO) films synthesized by modified chemical bath deposition (CBD). The optimum working temperature and pH was determined 50 +/- 5 degrees C and 9.8, respectively. Conditioning solution can functioned as an adhesive in CBD process which have been used for the first time. The effect of annealing temperature (450, 500 and 550 degrees C) was studied and the changing structural, elemental and morphological properties were investigated by using XRD, EDX and SEM devices, respectively. All polycrystalline films had [002] preferential orientation and the maximum crystallization was observed in ZnO films that annealed at 500 degrees C. Detailed optical properties (absorption, band gap energy) were investigated by using Uv-Vis spectroscopy. Optical transmittance spectra showed high optical absorption below to 370 nm in the range 300-900 nm. Gas sensing mechanism for 0.5 ppm NO2 gas was investigated by using home-made gas sensing chamber that sensor working at 200 degrees C and nano-flower dimensions severly affected to gas sensitivities.