Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Citation - WoS: 61Citation - Scopus: 74Solution-Processable Bodipy-Based Small Molecules for Semiconducting Microfibers in Organic Thin-Film Transistors(Amer Chemical Soc, 2016-05-23) Ozdemir, Mehmet; Choi, Donghee; Kwon, Guhyun; Zorlu, Yunus; Cosut, Bunyemin; Kim, Hyekyoung; Usta, HakanElectron-deficient pi-conjugated small molecules can function as electron-transporting semiconductors in various optoelectronic applications. Despite their unique structural, optical, and electronic properties, the development of BODIPY-based organic semiconductors has lagged behind that of other pi-deficient units. Here, we report the design and synthesis of two novel solution-proccessable BODIPY-based small molecules (BDY-3T-BDY and BDY-4T-BDY) for organic thin-film transistors (OTFTs). The new semiconductors were fully characterized by H-1/C-13 NMR, mass spectrometry, cyclic voltammetry, UV-vis spectroscopy, photoluminescence, differential scanning calorimetry, and thermogravimetric analysis. The single-crystal X-ray diffraction (XRD) characterization of a key intermediate reveals crucial structural properties. Solution-sheared top-contact/bottom-gate OTFTs exhibited electron mobilities up to 0.01 cm(2)/V center dot s and current on/off ratios of >10(8). Film microstructural and morphological characterizations indicate the formation of relatively long (similar to 0.1 mm) and micrometer-sized (1-2 mu m) crystalline fibers for BDY-4T-BDY-based films along the shearing direction. Fiber-alignment-induced charge-transport anisotropy (mu?/mu approximate to 10) was observed, and higher mobilities were achieved when the microfibers were aligned along the conduction channel, which allows for efficient long-range charge-transport between source and drain electrodes. These OTFT performances are the highest reported to date for a BODIPY-based molecular semiconductor, and demonstrate that BODIPY is a promising building block for enabling solution-processed, electron-transporting semiconductor films.Conference Object Citation - WoS: 25Citation - Scopus: 26Semiconducting Copolymers Based on Meso-Substituted BODIPY for Inverted Organic Solar Cells and Field-Effect Transistors(Wiley, 2017-12-11) Ozdemir, Mehmet; Kim, Sang Woo; Kim, Hyungsug; Kim, Myung-Gil; Kim, Bumjoon J.; Kim, Choongik; Usta, HakanThe synthesis, physicochemical, and optoelectronic properties of a new class of low band-gap (approximate to 1.3 eV) donor-acceptor copolymers based on a highly electron-deficient meso-5-(2-octyldodecyl)thiophene-substituted BODIPY pi-unit are presented. The polymeric solutions exhibit strong aggregation-dependent excitonic properties indicating the presence of enhanced pi-coherence as a result of strong interchain interactions. The polymeric semiconductor thin films prepared by spin coating show isotropic nodule-like grains with essentially no ordering in the out-of-plane direction. Field-effect hole mobilities of 0.005 cm(2) V-1.s(-1) are observed in bottom-gate top-contact organic field-effect transistors, and inverted bulk-heterojunction organic photovoltaics employing the polymer:PC71BM active layer exhibit excellent power conversion efficiencies of 6.2% with a short-circuit current of 16.6 mA cm(-2). As far as it is known, this is a record high value achieved to date for a boron-containing donor polymer in the photovoltaic literature indicating a significant enhancement in power conversion efficiency (>3-4 times). The findings clearly present that rationally designed BODIPY-based donor-acceptor copolymers can be a key player in photovoltaic applications.Article Citation - WoS: 20Citation - Scopus: 20Frequency and Electric Field Controllable Photodevice: FYTRONIX Device(Elsevier Science Bv, 2017-08) Tataroglu, A.; Al-Sehemi, Abdullah G.; Ozdemir, Mehmet; Ozdemir, Resul; Usta, Hakan; Al-Ghamdi, Ahmed A.; Yakuphanoglu, F.Al/p-Si/BODIPY/Al diode was fabricated by forming BODIPY organic layer on p-Si having ohmic contact. The electrical and photoresponse properties of the prepared diode were investigated in detail. The current-voltage ( I-V) measurements were performed under dark and various illumination intensities. It is observed that the photocurrent under illumination is higher than the dark current. The transient measurements indicate that the device exhibits both photodiode and photocapacitor behavior. We called this device as FYTRONIX device. The photoresponse behavior of the FYTRONIX device is controlled simultaneously by frequency and electric field. The FYRONIX device can be used as a photoresponse sensor in optoelectronic applications.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).