WoS İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394

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Author: search.filters.author.Demirel, GokhanPublisher: search.filters.publisher.Amer Chemical Soc

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Now showing 1 - 9 of 9
  • Article
    Citation - WoS: 28
    Citation - Scopus: 29
    Three-Dimensional Au-Coated Electrosprayed Nanostructured BODIPY Films on Aluminum Foil as Surface-Enhanced Raman Scattering Platforms and Their Catalytic Applications
    (Amer Chemical Soc, 2017-05-16) Yilmaz, Mehmet; Erkartal, Mustafa; Ozdemir, Mehmet; Sen, Unal; Usta, Hakan; Demirel, Gokhan
    The design and development of three-dimensional (3D) nanostructures with high surface-enhanced Raman scattering (SERS) performances have attracted considerable attention in the fields of chemistry, biology, and materials science. Nevertheless, electrospraying of organic smalt molecules on low-cost flexible substrates has never been studied to realize large-scale SERS-active platforms. Here, we report the facile, efficient, and low-cost fabrication of-Stable and reproducible Au-coated electrosprayed organic semiconductor films (Au@BDY-4TEBDY) on flexible regular aluminum foil at a large scale (5 cm X 5 cm) for practical SERS and catalytic applications. To this end, a well-designed-acceptor-donor-atceptor-type solution-processable molecular semiconductor, BDY-4T-BDY, developed by our group, is used because of its advantageous structural and electrical properties. The morphology of the electrosprayed organic film changes by solution concentration, and two different 3D morphologies with out-of-plane features are obtained. Highly uniform dendritic nanoribbons with sharp needle-like tips and vertically oriented nanoplates (similar to 50 nm thickness) are achieved when electrospraying solution concentrations of 240 and 253% w/v.(mgimL) are, respectively, used. When these electrosprayed organic films are coated with a nanoscopic thin (30 nm) Au layer, the resulting Au@BDY-4T-BDY platforms demonstrate remarkable SERS enhancement factors up to 1.7 X 10(6) with excellent Raman signal reproducibility (relative standard deviation <= 0.13) for methylene blue over the entire film. Finally, Au@BDY-4T-BDY films showed good catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol with rate constants of 1.3 X 10(-2) and 9.2 X 10(-3) min(-1). Our results suggest that electrospraying of rationally designed organic semiconductor molecules on flexible substrates holds great promise to enable low-cost, solution-processed, SERS-active platforms.
  • Article
    Citation - WoS: 11
    Citation - Scopus: 13
    Solution-Processable Indenofluorenes on Polymer Brush Interlayer: Remarkable N-Channel Field-Effect Transistor Characteristics Under Ambient Conditions
    (Amer Chemical Soc, 2023-08-15) Can, Ayse; Deneme, Ibrahim; Demirel, Gokhan; Usta, Hakan
    The development of solution-processable n-type molecularsemiconductorsthat exhibit high electron mobility (& mu;(e) & GE;0.5 cm(2)/(V & BULL;s)) under ambient conditions, along withhigh current modulation (I (on)/I (off) & GE; 10(6)-10(7)) andnear-zero turn on voltage (V (on)) characteristics,has lagged behind that of other semiconductors in organic field-effecttransistors (OFETs). Here, we report the design, synthesis, physicochemicaland optoelectronic characterizations, and OFET performances of a libraryof solution-processable, low-LUMO (-4.20 eV) 2,2 & PRIME;-(2,8-bis(3-alkylthiophen-2-yl)indeno[1,2-b]fluorene-6,12-diylidene)dimalononitrile small molecules, & beta;,& beta;& PRIME;-C (n) -TIFDMTs, having varied alkyl chain lengths (n = 8, 12, 16). An intriguing correlation is identifiedbetween the solid-isotropic liquid transition enthalpies andthe solubilities, indicating that cohesive energetics, which are tunedby alkyl chains, play a pivotal role in determining solubility. Thesemiconductors were spin-coated under ambient conditions on denselypacked (grafting densities of 0.19-0.45 chains/nm(2)) ultrathin (& SIM;3.6-6.6 nm) polystyrene-brush surfaces.It is demonstrated that, on this polymer interlayer, thermally induceddispersive interactions occurring over a large number of methyleneunits between flexible alkyl chains (i.e., zipper effect) are criticalto achieve a favorable thin-film crystallization with a proper microstructureand morphology for efficient charge transport. While C-8 and C-16 chains show a minimal zipper effect upon thermalannealing, C-12 chains undergo an extended interdigitationinvolving & SIM;6 methylene units. This results in the formationof large crystallites having lamellar stacking ((100) coherence length & SIM;30 nm) in the out-of-plane direction and highly favorablein-plane & pi;-interactions in a slipped-stacked arrangement. Uninterruptedmicrostructural integrity (i.e., no face-on (010)-oriented crystallites)was found to be critical to achieving high mobilities. The excellentcrystallinity of the C-12-substituted semiconductor thinfilm was also evident in the observed crystal lattice vibrations (phonons)at 58 cm(-1) in low-frequency Raman scattering. Two-dimensionalmicrometer-sized (& SIM;1-3 & mu;m), sharp-edged plate-likegrains lying parallel with the substrate plane were observed. OFETsfabricated by the current small molecules showed excellent n-channelbehavior in ambient with & mu;(e) values reaching & SIM;0.9cm(2)/(V & BULL;s), I (on)/I (off) & SIM; 10(7)-10(8), and V (on) & AP; 0 V. Our study notonly demonstrates one of the highest performing n-channel OFET devicesreported under ambient conditions via solution processing but alsoelucidates significant relationships among chemical structures, molecularproperties, self-assembly from solution into a thin film, and semiconductingthin-film properties. The design rationales presented herein may openup new avenues for the development of high-electron-mobility novelelectron-deficient indenofluorene and short-axis substituted donor-acceptor & pi;-architectures via alkyl chain engineering and interface engineering.
  • Conference Object
    Organic Semiconductor Based Surface-Enhanced Raman Spectroscopy Platforms
    (Amer Chemical Soc, 2018) Demirel, Gokhan; Usta, Hakan; Facchetti, Antonio
  • Conference Object
    New Method for Measuring the Temperature Change of Photothermal Au Nanostructures Using Smart Polymers
    (Amer Chemical Soc, 2015) Cavusoglu, Halit; Sakalak, Huseyin; Buyukbekar, Burak Zafer; Demirel, Gokhan; Citir, Murat; Yavuz, Mustafa Selman
  • Conference Object
    Nanothermometer: Measuring Temperature Change in Nanometer Scale on Photothermal Au Nanoparticles
    (Amer Chemical Soc, 2015) Sakalak, Huseyin; Cavusoglu, Halit; Buyukbekar, Burak Zafer; Demirel, Gokhan; Citir, Murat; Yavuz, Mustafa Selman
  • Conference Object
  • Conference Object
    Measuring Temperature Change on Photothermal Au Nanorod and Nanocage Upon Laser Irradiation
    (Amer Chemical Soc, 2015) Cavusoglu, Halit; Sakalak, Huseyin; Buyukbekar, Burak Zafer; Demirel, Gokhan; Citir, Murat; Yavuz, Mustafa Selman
  • Conference Object
    Determining Temperature Change on Photothermal Au Nanorod and Au Nanocage Using Smart Polymers
    (Amer Chemical Soc, 2015) Buyukbekar, Burak Zafer; Cavusoglu, Halit; Sakalak, Huseyin; Citir, Murat; Demirel, Gokhan; Yavuz, Mustafa Selman
  • Conference Object
    Design and Development of Functional Organic Small Molecules and Polymers for Optoelectronics
    (Amer Chemical Soc, 2016) Usta, Hakan; Demirel, Gokhan; Facchetti, Antonio; Muccini, Michele