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    Earth-abundant Cu 2 CoSnS 4 nanofibers for highly efficient H 2 evolution at soft interfaces
    (Wiley-VCH Verlag, 2015) Özel, Faruk; Yar, Adem; Aslan, Emre; Arkan, Emre; Aljabour, Abdalaziz; Can, M.; Patır, İmren Hatay
    Cu 2 CoSnS 4 (CCTS) nanofibers have been fabricated by electrospinning and exhibit an excellent morphology with an average nanofiber diameter of 150 nm. Polyacrylonitrile (PAN) was used as templating polymer that leads to a decrease in imperfections in the crystalline nanofibers. CCTS and Cu 2 ZnSnS 4 (CZTS) nanofibers, based on abundant and environmental friendly elements, efficiently enhanced the rates of biphasic proton reduction in the presence of an organic solubilized electron donor, decamethylferrocene (DMFc). This work paves the way for the exploration of copper-based chalcogenides as electrocatalysts for the hydrogen evolution reaction to replace noble metal Pt. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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    Electrospinning of Cu2ZnSnSe4-xSx nanofibers by using PAN as template
    (Elsevier Science Bv, 2015) Özel, Faruk; Kus, Mahmut; Yar, Adem; Arkan, Emre; Yigit, M. Zeliha; Aljabour, Abdalaziz; Buyukcelebi, Sumeyra; Tozlu, Cem
    We firstly demonstrate the synthesis of Cu2ZnSnSe4-xSx (CZTSeS) nanofibers through versatile electrospinning technique. Polyacrylonitrile (PAN) was used as templating polymer that leads to decrease in imperfections on crystal fibers and yields outstanding structure including a few defects with diameter around 250 nm. Sulfurization and/or selenization processes were carried out separately and simultaneously depending upon the demanded chemical structure. Detailed characterization and electrochemical response indicate their potential application for solar cells as p-type semiconductors. (C) 2014 Elsevier B.V. All rights reserved.
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    Flexible nanofiber based triboelectric nanogenerators with high power conversion
    (Elsevier, 2020) Yar, Adem; Karabiber, Abdulkerim; Özen, Abdurrahman; Özel, Faruk; Coşkun, Şahin
    Triboelectric nanogenerators (TENGs) convert small mechanical movements into electrical energy based on electrostatic principles. Nowadays, the energy efficiency of TENGs is low and needs to be increased for use in self-powered electronic devices. The energy efficiency can be enhanced by developing new dielectric materials with higher electrical charge capacity. In this study, PAN/ZnO and PAN/B(OH)(3) flexible nanofibers as a triboelectric contact layer are fabricated for the first time to improve the power production performance of polyacrylonitrile (PAN). In the experiments, PAN/ZnO and PAN/B(OH)(3) were used as tribopositive dielectric and polyvinyl butyral (PVB) was used as a tribonegative dielectric of TENGs. According to the results, the power density of TENGs changes with dielectric material sizes and load conditions. The peak power density of 3 x 3 cm PAN/B(OH)(3) reaches 6.67 Wm(-2) when the load is 33 MU. Since, the solution-based synthesized ZnO has limited crystallinity, no favorable effect was observed on the power production performance of PAN. The results demonstrated that facile and low-cost fabrication method in accordance with the new TENGs design shed light on a new route for the enhancement of high-performance TENGs. In addition, the fabricated PAN-based nanofibrous structures can be beneficial for the improvement of advanced triboelectric technology.
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    Transition Metal Dichalcogenides as Effective Dopants in Nanofiber-Based Triboelectric Nanogenerators
    (Wiley, 2024) Karabiber, Abdulkerim; Dirik, Ömer; Okbaz, Abdulkerim; Yar, Adem; Özen, Abdurrahman; Özel, Faruk
    Triboelectric nanogenerators (TENGs) are advanced energy harvesters that convert mechanical energy in diverse environments into electrical energy via static electrification and electrostatic induction. However, their performance needs to be improved to expand their area of use and become more practical. In this study, we introduced molybdenum disulfide (MoS2) and tungsten disulfide (WS2) as separate additives into polyacrylonitrile (PAN) to produce composite nanofibers via electrospinning, aiming to increase the electrical output of the TENGs. This method increased contact area by narrowing the nanofiber diameters, which is a key factor in enhancing the triboelectric effect. The incorporation of MoS2 or WS2, characterized by high specific surface area, interface polarization, quantum confinement effects, and strong electron acceptance and trapping capabilities, led to a significant increase in the dielectric constant and overall electrical performance of the TENGs. Experimental evaluations, connecting the TENGs to circuits with various resistive loads, determined optimal performance at a load resistance of 4.7 M Omega. In particular, the 5 wt% WS2@PAN & polyvinylbutral (PVB) and 5 wt% MoS2@PAN & PVB TENGs exhibited a remarkable peak power output of 40.5 mW, corresponding to a power density of 25.3 W/m2 and provided open circuit voltage of 1,026 V. The integration of 5 wt% MoS2 or 5 wt% WS2 led to more than a twofold increase in electrical power density compared to pristine PAN. These outcomes demonstrate the significant impact of transition metal dichalcogenides in enhancing the energy conversion efficiency of contact-separation mode TENGs, thereby contributing to the advancement of energy harvesting technology.