應用苯并呋喃於主鏈予體－受體高分子之異質接面太陽能電池元件研究

Abstract

在本研究中，我們分別使用施蒂勒(Stille)與鈴木(Suzuki)聚合一系列包含C-、Si-、N-鍵橋之聯噻吩(Bithiophene)與芴(Fluorene)推電子基團和2,1,3-苯并呋喃(2,1,3-Benzooxadiazole)強拉電子基團高分子−PCyTBO、PCySiTBO、PCyNTBO、PFTBO、PAFTBO和PCTBO。PCyTBO、PCySiTBO和PCyNTBO高分子具有寬廣吸收光譜(300−700 nm)，而且PCySiTBO具有結晶性可以增加載子傳輸(短路電流高達10.8 mA cm–2)，其中PCySiTBO與PC71BM摻混比例1：1製成元件並使用1,8-二碘辛烷(1,8-diiodooctane)當作添加劑可得效率高達5.0%。另外，PFTBO、PAFTBO和PCTBO高分子具有不錯的溶解度和較低之最高佔有分子軌域(其中PFTBO之HOMO能階為−5.53 eV)，此高分子PFTBO、PAFTBO和PCTBO分別具有不錯的電洞遷移率(3.1 × 10–5, 8.7 × 10–5, 1.8 × 10–4 cm2 V–1 s–1)，PCTBO具有平均分子量46.3 kD且製備成元件顯示其具有較大的開路電壓可高達1.04 V，且元件摻混PC61BM不需其他前製程可得效率4.1%。

In this study, we used Stille and Suzuki coupling polymerization to synthesize a series of polymers (PCyTBO, PCySiTBO, PCyNTBO, PFTBO, PAFTBO and PCTBO) containing electron-rich C-, Si-, N-bridged bithiophene、Fluorene and strong electron-deficient 2,1,3-Benzooxadiazole units respectively. Polymers (PCyTBO, PCySiTBO and PCyNTBO) exhibited broad spectral absorptions (300−700 nm), and PCySiTBO showed some crystallinity with increased transparency (Jsc as high as 10.8 mA cm–2). The photovoltaic device incorporating the PCySiTBO/PC71BM (1:1) blend system and 1,8-diiodooctane (2 vol %) as an additive exhibited good performance up to 5.0%. Besides, Polymers (PFTBO, PAFTBO and PCTBO) exhibited good solubility, low-lying energy for the highest occupied molecular orbital (HOMO) (as low as −5.53 eV for PFTBO). These polymers also possess good hole mobility of 3.1 × 10–5, 8.7 × 10–5, 1.8 × 10–4 cm2 V–1 s–1 for PFTBO, PAFTBO and PCTBO, respectively. As a result, The best performance was obtained when number-average molecular weughts (Mn) are around 46.3 kDa and photovoltaic devices showed high open circuit votage (Voc as high as 1.04 V for PCTBO). And power conversion efficiency up to 4.1% was blended PC61BM without any post treatment.