WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394
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Article Citation - WoS: 88Citation - Scopus: 83Organic Light-Emitting Physically Unclonable Functions(Wiley-VCH Verlag GmbH, 2021-12-22) Kayaci, Nilgun; Ozdemir, Resul; Kalay, Mustafa; Kiremitler, N. Burak; Usta, Hakan; Onses, M. SerdarThe development of novel physically unclonable functions (PUFs) is of growing interest and fluorescent organic semiconductors (f-OSCs) offer unique advantages of structural versatility, solution-processability, ease of processing, and great tuning ability of their physicochemical/optoelectronic/spectroscopic properties. The design and ambient atmosphere facile fabrication of a unique organic light-emitting physically unclonable function (OLE-PUF) based on a green-emissive fluorescent oligo(p-phenyleneethynylene) molecule is reported. The OLE-PUFs have been prepared by one-step, brief (5 min) thermal annealing of spin-coated nanoscopic films (approximate to 40 nm) at a modest temperature (170 degrees C), which results in efficient surface dewetting to form randomly positioned/sized hemispherical features with bright fluorescence. The random positioning of molecular domains generated the unclonable surface with excellent uniformity (0.50), uniqueness (0.49), and randomness (p > 0.01); whereas the distinctive photophysical and structural properties of the molecule created the additional security layers (fluorescence profile, excited-state decay dynamics, Raman mapping/spectrum, and infrared spectrum) for multiplex encoding. The OLE-PUFs on substrates of varying chemical structures, surface energies and flexibility, and direct deposition on goods via drop-casting are demonstrated. The OLE-PUFs immersed in water, exposed to mechanical abrasion, and read-out repeatedly via fluorescence imaging showed great stability. These findings clearly demonstrate that rationally engineered solution-processable f-OSCs have a great potential to become a key player in the development of new-generation PUFs.Article Citation - WoS: 68Citation - Scopus: 68Micro-/Nanostructured Highly Crystalline Organic Semiconductor Films for Surface-Enhanced Raman Spectroscopy Applications(Wiley-VCH Verlag GmbH, 2015-08-11) Yilmaz, Mehmet; Ozdemir, Mehmet; Erdogan, Hakan; Tamer, Ugur; Sen, Unal; Facchetti, Antonio; Demirel, GokhanThe utilization of inorganic semiconductors for surface-enhanced Raman spectroscopy (SERS) has attracted enormous interest. However, despite the technological relevance of organic semiconductors for enabling inexpensive, large-area, and flexible devices via solution processing techniques, these p-conjugated systems have never been investigated for SERS applications. Here for the first time, a simple and versatile approach is demonstrated for the fabrication of novel SERS platforms based on micro-/nanostructured 2,7-dioctyl[1]benzothieno[3,2-b][1] benzothiophene (C8-BTBT) thin films via an oblique-angle vapor deposition. The morphology of C8-BTBT thin films is manipulated by varying the deposition angle, thus achieving highly favorable 3D vertically aligned ribbon-like micro-/nanostructures for a 90 degrees deposition angle. By combining C8-BTBT semiconductor films with a nanoscopic thin Au layer, remarkable SERS responses are achieved in terms of enhancement (approximate to 10(8)), stability (>90 d), and reproducibility (RSD < 0.14), indicating the great promise of Au/C8-BTBT films as SERS platforms. Our results demonstrate the first example of an organic semiconductor-based SERS platform with excellent detection characteristics, indicating that p-conjugated organic semiconductors have a great potential for SERS applications.Article Citation - WoS: 18Citation - Scopus: 20Electrochemical Polymerization of Ambipolar Carbonyl-Functionalized Indenofluorene With Memristive Properties(Elsevier, 2019-08) Figa, Viviana; Usta, Hakan; Macaluso, Roberto; Salzner, Ulrike; Ozdemir, Mehmet; Kulyk, Bohdan; Bruno, MaurizioCarbonyl-functionalized indenofluorene was electropolymerized with a high faradaic efficiency of 85% and the solid state properties of the resulting polymeric thin films were investigated. They displayed modular optical properties depending on their oxidation state. The approach used for inorganic semiconductors was applied to polyindeonofluorene derivative. Mott-Schottky analysis evidenced a switching from p-type to n-type electrical conduction, suggesting an ambipolar behaviour of the polymer. As an application, flexible organic memristors were fabricated and resistive switching properties were observed.Article Citation - WoS: 19Citation - Scopus: 20A Solution-Processable Meso-Phenyl N-Channel Semiconductor With Enhanced Fluorescence Emission(Wiley-VCH Verlag GmbH, 2019-06-26) Ozcan, Emrah; Ozdemir, Mehmet; Ho, Dongil; Zorlu, Yunus; Ozdemir, Resul; Kim, Choongik; Cosut, BunyeminThe cover feature shows the delicate balance between locally excited (LE) and twisted intramolecular charge-transfer (TICT) states, which could be controlled by solvent polarity and nano-aggregation, of a meso-phenyl-BODIPY-based fluorescent semiconductor. The dihedral angle between the meso-aromatic unit and BODIPY pi-core was found to be the key factor in this balance. This is the first report of highly emissive characteristics for an A-D-A type BODIPY-based n-channel semiconductor. Details are given in the Full Paper by B. Cosut, H. Usta, C. Kim, and co-workers (DOI: 10.1002/cplu.201900317).