Photonics / Fotonik

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

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Access type: Open accessAuthor: search.filters.author.Açıkbaş, Yaser

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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: 6
    Anisotropic Etching of Cvd Grown Graphene for Ammonia Sensing
    (Institute of Electrical and Electronics Engineers Inc., 2022) Yağmurcukardeş, Nesli; Bayram, Abdullah; Aydın, Hasan; Yağmurcukardeş, Mehmet; Açıkbaş, Yaser; Peeters, François M.; Çelebi, Cem
    Bare chemical vapor deposition (CVD) grown graphene (GRP) was anisotropically etched with various etching parameters. The morphological and structural characterizations were carried out by optical microscopy and the vibrational properties substrates were obtained by Raman spectroscopy. The ammonia adsorption and desorption behavior of graphene-based sensors were recorded via quartz crystal microbalance (QCM) measurements at room temperature. The etched samples for ambient NH3 exhibited nearly 35% improvement and showed high resistance to humidity molecules when compared to bare graphene. Besides exhibiting promising sensitivity to NH3 molecules, the etched graphene-based sensors were less affected by humidity. The experimental results were collaborated by Density Functional Theory (DFT) calculations and it was shown that while water molecules fragmented into H and O, NH3 interacts weakly with EGPR2 sample which reveals the enhanced sensing ability of EGPR2. Apparently, it would be more suitable to use EGRP2 in sensing applications due to its sensitivity to NH3 molecules, its stability, and its resistance to H2O molecules in humid ambient.
  • Article
    Citation - WoS: 17
    Citation - Scopus: 20
    Electrospun Polyacrylonitrile (pan) Nanofiber: Preparation, Experimental Characterization, Organic Vapor Sensing Ability and Theoretical Simulations of Binding Energies
    (Springer, 2022) İnce Yardımcı, Atike; Yağmurcukardeş, Nesli; Yağmurcukardeş, Mehmet; Çapan, İnci; Erdoğan, Matem; Çapan, Rıfat; Tarhan, Özgür; Açıkbaş, Yaser
    In this study, polyacrilonitrile (PAN) nanofibers obtained by electrospinning were directly coated on the surface of a quartz crystal microbalance (QCM) and were investigated for their sensing characteristics against chloroform, dichloromethane and carbon tetrachloride as volatile organic compounds (VOCs). PAN nanofibers were characterized by SEM, DSC, Raman Spectroscopy, and FT-IR and the results indicated that beadless and regular nanofibers with the average diameter of 182.7 ± 32 nm were obtained. Kinetic measurements indicated that electrospun PAN nanofibers were sensitive to the VOCs and they were appropriate for sensing applications of chlorine compounds. The reproducibility of PAN nanofiber sensor was also shown in this study. The results revealed that the diffusion coefficients of VOCs increased with the order carbontetrachloride < dichloromethane < chloroform which was supported by the density functional theory (DFT) simulations that revealed the highest binding energy for chloroform.