Photonics / Fotonik

Permanent URI for this collectionhttps://hdl.handle.net/11147/2590

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Access Right: Closed AccessAuthor: search.filters.author.Yağmurcukardeş, Nesli

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  • Article
    Citation - WoS: 9
    Citation - Scopus: 11
    Electrospun Polyacrylonitrile (pan)/Polypyrrole (ppy) Nanofiber-Coated Quartz Crystal Microbalance for Sensing Volatile Organic Compounds
    (Springer, 2023) Yağmurcukardeş, Nesli; İnce Yardımcı, Atike; Yağmurcukardeş, Mehmet; Çapan, İnci; Erdoğan, Matem; Çapan, Rifat; Açıkbaş, Yaser
    In this study, electrospun polyacrylonitrile (PAN)/polypyrrole (PPy) nanofibers (NFs) coated quartz crystal microbalance (QCM) were investigated for their sensing characteristics against six different volatile organic compounds (VOCs): chloroform, dichloromethane, carbon tetrachloride, benzene, toluene and xylene. SEM, TEM, FT-IR and TGA analysis were carried out for the characterization of PAN/PPy nanofibers and characterization results of PAN/PPy NFs showed that these nanofibers were morphologically well-arranged and straightforward with a cylindrical shape with the average fiber diameter of 253.17 +/- 27 nm. Among all the gas measurement tests, dichloromethane displayed the highest response values for PAN/PPy coated QCM sensors. When the reproducibility of kinetic studies for PAN/PPy NFs coated QCM sensors were examined, the most repetitive results were obtained by this QCM sensor during dichloromethane investigation and the diffusion coefficients of VOCs for the first and second regions increased with the order of xylene < toluene < benzene < carbontetrachloride < chloroform < dichloromethane. The sensitivities of the PAN/PPy nanofibers-coated QCM sensor against organic vapors are determined between 4.71 and 6.17 (Hz ppm(-1)) x 10(-4). As a result, PAN/PPy nanofibers exhibited high sensitivity and selectivity for VOCs sensor applications, especially for dichloromethane.
  • Article
    Citation - WoS: 7
    Citation - Scopus: 8
    Stable janus TaSe2 single-layers via surface functionalization
    (Elsevier Ltd., 2021) Kahraman, Zeynep; Başkurt, Mehmet; Yağmurcukardeş, Nesli; Chaves, A.; Şahin, Hasan
    First-principles calculations are performed in order to investigate the formation of Janus structures of single-layer TaSe2. The structural optimizations and phonon band dispersions reveal that the formation and stability of hydrogenated (HTaSe2), fluorinated (FTaSe2), and the one-side hydrogenated and one-side fluorinated (Janus-HTaSe2F) single-layers are feasible in terms of their phonon band dispersions. It is shown that bare metallic single-layer TaSe2 can be turned into a semiconductor as only one of its surface is functionalized while it remains as a metal via its two surfaces functionalization. In addition, the semiconducting nature of single-layers HTaSe2 and FTaSe2 and the metallic behavior of Janus TaSe2 are found to be robust under applied uniaxal strains. Further analysis on piezoelectric properties of the predicted single-layers reveal the enhanced in-plane and out-of-plane piezoelectricity via formed Janus-HTaSe2F. Our study indicates that single-layer TaSe2 is a suitable host material for surface functionalization via fluorination and hydrogenation which exhibit distinctive electronic and vibrational properties. © 2020 Elsevier B.V.