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Öğe Study of some sensitizers for gel polymer electrolyte based sensitized solar cells (SSCs)(ELSEVIER, 2019) Mingsukang, M. A.; Hisamuddin, S. N.; Baharun, N. N. S.; Lee, Y. C.; Abidin, Z. H. Z.; Buraidah, M. H.; Karakas, A.The performance of phthaloychitosan gel polymer electrolyte (GPE) based sensitized solar cells (SSCs) fabricated with different types of sensitizer have been studied in this work. Five types of sensitizer were used viz., curcumin, chlorophyll, (E)-4-hydroxyl-3-((4-iodophenyl)diazenyl)-2H-chromen-2-one (CAD5), (E)-4-hydroxyl-3-((4-methoxyphenyl) diazenyl)-2H-chromen-2-one (CAD7) and cadmium sulphide (CdS). These sensitizers were designated as S1, S2, S3, S4 and S5 respectively. The performance of the sensitized solar cells (SSCs) has been characterized and the experimental results showed that S1 (SSC fabricated with curcumin dye sensitizer) exhibits the best performance with short circuit current density (J(sc)) of 3.18 mA cm(-2), open circuit voltage (V-oc) of 0.41 V, fill factor (FF) 0.57 and power conversion efficiency (PCE) of 0.73%. (C) 2019 Elsevier Ltd. All rights reserved.Öğe Some optical properties of melanin thick film(ELSEVIER, 2019) Akın, Ü.; Çelik, İlhami; Avcı, Çağrı; Tuğluoğlu, Nihat; Yüksel, Ömer FarukThe melanin obtained from brown-black sheep wool was prepared in the form of thick film by using drop casting method on the soda-lime glass substrate. The optical properties of the melanin thick film have been investigated by means of the optical measurements. It was observed that the thick film showed high transmittance value nearly up to 84 % in the IR spectral region and it showed very high absorbance in both UV and visible regions. From standard optical analysis, it was observed that melanin thick film had the properties of the semiconductors with indirect band gap, and the band gap energy value was found as 1.24 eV. Also, it was seen that calculated refractive index of the melanin thick film varies between 1.37 and 1.63 throughout the spectral region considered. (C) 2019 Elsevier Ltd. All rights reserved.Öğe Nonlinear optical properties of zinc oxide thin films produced by pulsed laser deposition(ELSEVIER, 2019) Kepceoğlu, A.; Gezgin, S. Yiğit; Gündoğdu, Y.; Küçükçelebi, H.; Kılıç, H. S.In this work, the nonlinear optical properties of Zinc Oxide (ZnO) thin films produced on microscope slide glass substrates at room temperature (RT) using Pulsed Laser Deposition (PLD) method has been presented. PLD system consists of a vacuum chamber (pumped by a turbo molecular pump, backed with a rotary pump), rotating sample and substrate holders, optical thickness measurement system, infrared temperature measurement system and a nanosecond laser system. Previously deposition vacuum chamber evacuated down to similar to 10(-8) mbar and deposition was taken place about 1.3x10(-1) mbar oxygen background gas pressure value. Morphological properties of thin films were obtained by Atomic Force Microscopy (AFM) that shows homogenous and smooth film structure. Thin films crystallinity were investigated by using X-Ray Diffraction (XRD) method and showed that polycrystalline ZnO structure with the largest peak corresponding to (002) orientation but some films contain Zn with (101) orientation. The thicknesses of the films were deduced from reflectance measurement using a fitting software and crosschecked with profilometer and AFM measurements. The thickness of the films ranged between 10 nm and 220 nm. Linear optical properties were obtained by using UV-VIS Spectrometer. Furthermore, we presented the nonlinear optical properties of the ZnO thin films that were obtained by the z-scan method. (C) 2019 Elsevier Ltd. All rights reserved.Öğe Investigation of conversion efficiency of n-ZnO/p-Si heterojunction device produced by pulsed laser deposition (PLD)(ELSEVIER, 2019) Gezgin, Serap Yiğit.; Kepceoğlu, Abdullah.; Toprak, Ahmet.; Kılıç, Hamdi Şükür.In this study, n-ZnO/p-Si heterojunction was produced by growing polycrystalline Zinc Oxide (ZnO) thin films on p-type Si (100) substrate at 500 mu m thickness using Pulsed Laser Deposition (PLD) method. The crystalline and morphologic structure of ZnO thin film were analysed by X-ray diffraction (XRD) and Atomic Force Microscopy (AFM) techniques. The photovoltaic (PV) property of n-ZnO/p-Si heterojunction was investigated by using current-voltage (J-V) measurement under illumination at 70 mW/cm(2). The silver (Ag) metal thin film was deposited by PLD to make ohmic contacts to the n-ZnO/p-Si heterojunction structure. The barrier height and the ideality factor were calculated to be 0.51 eV and 12.37, respectively, at room temperature (RT). The largest values of open circuit voltage (V-oc) and short circuit current density (J(sc)) were about 250 mV and 1.63 mA/cm(2), respectively. The photoelectric conversion efficiency in the range of 0.12% have been achieved and presented in this paper. (C) 2019 Elsevier Ltd. All rights reserved.Öğe International congress on semiconductor materials and devices(ELSEVIER, 2019) Yüksel, Ö. Faruk.; Türüt, Abdülmecit; Karabulut, Elife Öznur.The International Congress on Semiconductor Materials and Devices (ICSMD-2017) was held in Konya, Turkey for the first time at Selcuk University between the 17th and 19th of August, 2017. The main aim of the congress was to bring together researchers from both academic and industrial community, working in the field of semiconductor science and technology, and to promote the exchange of their ideas and results, as well as to foster collaboration between them. The scientific topic of the congress spanned a broad range of research fields on 1) Semiconductor Materials and Devices, 2) Thin Films: Surface and Interface, 3) Nanofabrication, Nanotubes, and Nanowires, 4) Photonic Devices and Sensors, 5) Organic Semiconductors and Devices, 6) Magnetic Semiconductors, 7) Biological Applications of Semiconductors, 8) Computational Methods Applied to Semiconductor Materials. There were about 200 national and international participants comprised of university students, academicians, and experts from the industry. A total of 65 oral presentations, including 8 invited speakers, were given and about 150 posters were presented. The presentations mostly gave a critical assessment of existing work and future directions in semiconductor growth and device technology, including materials characterization and device fabrication processes, growth of semiconductors, photovoltaic materials, Schottky barrier diodes and hybrid organic/inorganic semiconductor devices. This special issue of Materials Today: Proceedings features 26 peer-reviewed articles which provide a general overview of topics in the field of semiconductor materials and devices discussed in ICSMD-2017. The guest editors are thankful to all the participants, and all the authors who contributed their time and effort submitting their excellent and extended works to the present special issue. The guest editors would also like to thank all the reviewers for their valuable comments and suggestions to the authors on improving the quality of the papers. (C) 2019 Elsevier Ltd. All rights reserved.Öğe Femtosecond laser ablation synthesis of nanoparticles and nano-hybrides in ethanol medium(ELSEVIER, 2019) Gündoğdu, Yasemin.; Kepceoğlu, Abdullah.; Yiğit Gezgin, Serap.; Küçükçelebi, Hayrettin.; Kılıç, Hamdi Şükür.The nanoparticle production has a significant importance because of its unique optical properties in molecular biology and medicine. Plasmonic metallic nanoparticles are widely used in cancer monitoring studies as contrast agents on the account of their surface plasmon resonance (SPR) effect. Beside, silicon (Si) semiconductor nanoparticles can provide several beneficial properties that they are used commonly intensifying the detecting signals. Nanoalloys/Nanohybides/Nanocomposites are more functional materials than a single material structure and having many restrictions. At that point, the application of Pulsed Laser Ablation (PLA) technique has many advantages if applied in the liquid. Since no any chemical technique is applied, this procedure promises a clean synthesis process; it is a simple and economical technique in the production process. It provides some possibilities to generate particles in the desired size, shape and density, and these properties of nanoparticles produced can be controlled by controlling the laser parameters. In this work, we have focused on the production of nanoparticles to rid off chemical processes using femtosecond laser ablation technique, and this technique presents a process to reach the fast and reliable results for production of nanoshells, nanocomposites and all nanoforms of particles. We have produced Si@Au nanohybrids in ethanol medium using femtosecond laser ablation depending on laser pulse energy. Absorption spectra were recorded day by day to determine the optical characteristics of produced nanoparticles within these time durations, Transmission Electron Microscopy (TEM) images were obtained for monitoring and determining the size/structure of nanoparticles, energy dispersive spectroscopy (EDS) for material compositions were produced, these results obtained are presented in the scope of this paper. (C) 2019 Elsevier Ltd. All rights reserved.
