標題: Dithienocarbazole-Based Ladder-Type Heptacyclic Arenes with Silicon, Carbon, and Nitrogen Bridges: Synthesis, Molecular Properties, Field-Effect Transistors, and Photovoltaic Applications
作者: Wu, Jhong-Sian
Cheng, Yen-Ju
Lin, Tai-Yen
Chang, Chih-Yu
Shih, Peng-I.
Hsu, Chain-Shu
應用化學系
Department of Applied Chemistry
關鍵字: ladder-type structures;polymer solar cells;field-effect transistors
公開日期: 24-四月-2012
摘要: A new class of ladder-type dithienosilolo-carbazole (DTSC), dithienopyrrolo-carbazole (DTPC), and dithienocyclopenta-carbazole (DTCC) units is developed in which two outer thiophene subunits are covalently fastened to the central 2,7-carbazole cores by silicon, nitrogen, and carbon bridges, respectively. The heptacyclic multifused monomers are polymerized with the benzothiadiazole (BT) acceptor by palladium-catalyzed cross-coupling to afford three alternating donor-acceptor copolymers poly(dithienosilolo-carbazole-alt-benzothiadiazole) (PDTSCBT), poly(dithienocyclopenta-carbazole-alt-benzothiadiazole) (PDTCCBT), and poly(dithienopyrrolo-carbazole-alt-benzothiadiazole) (PDTPCBT). The silole units in DTSC possess electron-accepting ability that lowers the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of PDTSCBT, whereas stronger electron-donating ability of the pyrrole moiety in DTPC increases the HOMO and LUMO energy levels of PDTPCBT. The optical bandgaps (Egopt) deduced from the absorption edges of thin film spectra are in the following order: PDTSCBT (1.83 eV) > PDTCCBT (1.64 eV) > PDTPCBT (1.50 eV). This result indicated that the donor strength of the heptacyclic arenes is in the order: DTPC > DTCC > DTSC. The devices based on PDTSCBT and PDTCCBT exhibited high hole mobilities of 0.073 and 0.110 cm2 V-1 s-1, respectively, which are among the highest performance from the OFET devices based on the amorphous donor-acceptor copolymers. The bulk heterojunction photovoltaic device using PDTSCBT as the p-type material delivered a promising efficiency of 5.2% with an enhanced open circuit voltage, Voc, of 0.82 V.
URI: http://hdl.handle.net/11536/16025
ISSN: 1616-301X
期刊: ADVANCED FUNCTIONAL MATERIALS
Volume: 22
Issue: 8
結束頁: 1711
顯示於類別:期刊論文


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