Poly(thieno[3,2-b]thiophene-alt-bithiazole): A D鈥揂 Copolymer Donor Showing Improved Photovoltaic Performance with Indene-C60 Bisadduct Acceptor

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• 作者：Xia Guo ; Maojie Zhang ; Lijun Huo ; Chaohua Cui ; Yue Wu ; Jianhui Hou ; Yongfang Li
• 刊名：Macromolecules
• 出版年：2012
• 出版时间：September 11, 2012
• 年：2012
• 卷：45
• 期：17
• 页码：6930-6937
• 全文大小：528K
• 年卷期：v.45,no.17(September 11, 2012)
• ISSN：1520-5835

文摘

A new D鈥揂 copolymer, poly(thieno[3,2-b]thiophene-alt-bithiazole) (PTTBTz), based on thieno[3,2-b]thiophene donor unit and bithiazole acceptor unit, was synthesized by the Pd-catalyzed Stille-coupling reaction for the application as donor material in polymer solar cells (PSCs). PTTBTz film possesses high thermal stability with 5% weight-loss temperature at 450 掳C, a lower-lying HOMO energy level at 鈭?.20 eV, a higher hole mobility of 6.45 脳 10^鈥? cm²/(V s), and a crystalline structure. Photovoltaic performance of the polymer was investigated with [6,6]-phenyl-C₇₁-butyric acid methyl ester (PC₇₀BM) or indene-C₆₀ bisadduct (ICBA) as acceptor and with 3% DIO additive. The power conversion efficiency (PCE) of the PSC based on PTTBTz:ICBA (1:1 w/w) reached 5.35% with a high V_oc of 1.03 V, a J_sc of 8.55 mA/cm², and an FF of 0.608, whereas the PCE of the PSC based on PTTBTz:PC₇₀BM (1:1 w/w) was 4.57% with a V_oc of 0.82 V, a J_sc of 9.89 mA/cm², and an FF of 0.563, under the illumination of AM1.5, 100 mW/cm². PTTBTz is one of the D鈥揂 copolymers that shows better photovoltaic performance with ICBA as acceptor than PC₇₀BM. PTTBTz/ICBA could be a promising front active layer for high-efficiency tandem PSC because of its high V_oc.