Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Conference Object Citation - WoS: 26Citation - 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: 17Citation - Scopus: 19Optimized Activation of Solution-Processed Amorphous Oxide Semiconductors for Flexible Transparent Conductive Electrodes(Wiley, 2017-12-21) Choi, Byung Doo; Park, Joohyung; Baeg, Kang-Jun; Kang, Minji; Heo, Jae Sang; Kim, Seonhyoung; Kim, Myung-GilHere, the preparation of transparent amorphous oxide semiconductor (AOS) films with unprecedented conductivity via an optimized activation process under hydrogen atmosphere for applications in solution-processed large-area optoelectronics is reported. Owing to their high cost and mechanical vulnerability, conventional vacuum-processed indium-tin oxide (ITO) electrodes are inappropriate for use in next-generation flexible and wearable electronic devices and systems. As an alternative to the ITO electrodes, solution-processed AOS films, such as alpha-IZO and alpha-ZITO, with an optimized composition and postreduction treatment under hydrogen show the highest electrical conductivity of approximate to 300 S cm(-1) and a high optical transmittance of over 90% at 550 nm. The microstructures and electrical properties of these AOS films are also studied in order to determine the optimized chemical composition and postreduction conditions. It is found that a controlled hydrogen reduction treatment of AOS films is critical for achieving high electrical conductivity by suppressing the surface morphology degradation and grain boundary disconnection. Furthermore, the alpha-IZO transparent conductive electrodes are successfully implemented for high efficiency organic photovoltaic cells based on the PTB7/PC71BM active layers. This technique promises the low-cost fabrication of high mobility and/or conductive AOSs for their applications in large-area transparent and flexible optoelectronics.