Browsing by Author "Lin, Fang-Yu"

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Force Sensor Design and Measurement for Endodontic Therapy
(2013-07-01)
Tsao, Chih-Chiang
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Lin, Fang-Yu
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Liou, Ji-Wei
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Wen, Ping-Han
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Peng, Chieh-Chung
To assist endodontic therapy, in this paper, a force sensor is designed and fabricated for measuring the axial force and the bending moment simultaneously. By detecting the bending moment, we can know the severity of bending. Axial force detection is also desired, as excessive axial forces may result in instrument buckling or even root canal perforation. This paper installs three sensing cells in each of two planes to detect the bending direction. Each sensing cell consists of a pressure-sensitive electric conductive rubber and an electrode. The size of the force sensor is 1.4-mm wide and 6-mm high for matching the size of endodontic instruments and making it feasible in the endodontic treatment. Experimental results on accuracy, repeatability, and nonlinearity are presented to validate the proposed sensor.
Naphthobisthiadiazole-Based Selenophene-Incorporated Quarterchalcogenophene Copolymers for Field-Effect Transistors and Polymer Solar Cells
(2019-03-27)
Cao, Fong-Yi
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Lin, Fang-Yu
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Tseng, Cheng-Chun
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Hung, Kai-En
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Hsu, Jhih-Yang
In this research, we developed six new selenophene-incorporated naphthobisthiadiazole-based donor-acceptor polymers PNT2Th2Se-OD, PNT2Se2Th-OD, PNT4Se-OD, PNT2Th2Se-DT, PNT2Se2Th-DT, and PNT4Se-DT. The structure-property relationships have been systematically established through the comparison of their structural variations: (1) isomeric biselenophene/bithiophene arrangement between PNT2Th2Se and PNT2Se2Th polymers, (2) biselenophene/bithiophene and quarterselenophene donor units between PNT2Th2Se/PNT2Se2Th and PNT4Se polymers, and (3) side-chain modification between the 2-octyldodecylthiophene (OD)- and 2-decyltetradecyl (DT)-series polymers. The incorporation of selenophene units in the copolymers induces stronger charge transfer to improve the light-harvesting capability while maintaining the strong intermolecular interactions to preserve the intrinsic crystallinity for high carrier mobility. The organic field-effect transistor device using PNT2Th2Se-OD achieved a high hole mobility of 0.36 cm(2) V-1 s(-1) with an on/off ratio of 1.9 x 10(5). The solar cells with PNT2Th2Se-OD:PC71BM exhibited a power conversion efficiency of 9.47% with a V-oc of 0.68 V, an fill factor of 67%, and an impressive J(SC), of 20.69 mA cm(-2).
Selenophene-Incorporated Quaterchalcogenophene-Based Donor-Acceptor Copolymers To Achieve Efficient Solar Cells with J(sc) Exceeding 20 mA/cm(2)
(2017-12-12)
Cao, Fong-Yi
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Tseng, Cheng-Chun
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Lin, Fang-Yu
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Chen, Yuzhong
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Yan, He
Three selenophene-incorporated quaterchalcogenophene-based donoracceptor copolymers PFBT2Th2Se, PFBT2Se2Th, and PFBT4Se are designed and synthesized. To systematically fine-tune the molecular properties and investigate the chalcogen effect, PFBT2Th2Se and PFBT2Se2Th hybridize two thiophenes and two selenophenes as the donor with different isomeric main-chain placement while thiophene-free PFBT4Se uses quaterselenophene as the donor. On account of the selenophenes advantageous features such as higher quinoidal population and higher molecular polarizability, the three polymers show good light-harvesting ability, strong intermolecular interactions, high crystallinity, and high charge mobilities. Bulk-heterojunction solar cells incorporating these selenophene-containing polymers have exhibited promising photovoltaic performance with impressive current densities over 20 mA/cm(2). The device with the PFBT2Se2Th:PC71BM blend showed a PCE of 9.02% with a J(sc) of 21.02 mA/cm(2). In addition, the device using quaterselenophene-based PFBT4Se:PC71BM blend exhibited a PCE of 8.92% with a superior J(sc) of 22.63 mA/cm(2) which represents one of the highest current densities from polymer:fullerene-based solar cells reported in the literature.
Synthesis and Isomeric Effects of Ladder-Type Alkylated Terbenzodithiophene Derivatives
(2016-03-18)
Chen, Yung-Lung
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Hsu, Jhih-Yang
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Lin, Fang-Yu
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Lai, Yu-Ying
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Chou, Hsiao-Chieh
A new class of heptacyclic ladder-type terbenzodithiophene (TBDT) structures merging three fused benzodithophenes was developed. Two TBDT conjugated isomers, named as syn-TBDT and anti-TBDT, where the two thienyl rings in the outmost BDT units are in the syn- and anti-fashion, are designed. Two decyl groups are introduced to their 6,13 and 7,14-positions to form four isomeric 6,13-syn-TBDT, 7,14-syn-TBDT, 6,13-anti-TBDT, and 7,14-anti-TBDT structures which are constructed by the DBU-induced 6-benzannulation involving propargyl-allenyl isomerization of the dieneyne moieties in the corresponding precursors followed by 6 pi-electro-cyclization/aromatization, while isomeric TD-syn-TBDT and TD-anti-TBDT with four decyl groups substituted at 6,7,13,14-positions are synthesized via palladium-catalyzed dialkylacetylene insertion/C-H arylation of the corresponding iodobiaryl precursors. The intrinsic properties can be modulated by molecular manipulation of the main-chain and side-chain isomeric structures. anti-TBDT derivatives exhibit higher melting points, larger bandgaps, stronger intermolecular interactions, and higher mobility than the corresponding syn-TBDT analogues. These molecules can be further utilized as building blocks to make various TBDT-based materials for optoelectronic applications.