Solution-Processable Organic Molecule Photovoltaic Materials with Bithienyl-benzodithiophene Central Unit and Indenedione End Groups

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• 作者：Suling Shen ; Pei Jiang ; Chang He ; Jing Zhang ; Ping Shen ; Yi Zhang ; Yuanping Yi ; Zhanjun Zhang ; Zhibo Li ; Yongfang Li
• 刊名：Chemistry of Materials
• 出版年：2013
• 出版时间：June 11, 2013
• 年：2013
• 卷：25
• 期：11
• 页码：2274-2281
• 全文大小：456K
• 年卷期：v.25,no.11(June 11, 2013)
• ISSN：1520-5002

文摘

Two solution-processable acceptor鈥揹onor鈥揳cceptor (A-D-A) structured organic molecules with bithienyl-substituted benzodithiophene (BDTT) as central and donor unit, indenedione (ID) as acceptor unit and end groups, and thiophene (T) or bithiophene (bT) as 蟺-bridges, D1 and D2, are designed and synthesized for the application as donor materials in organic solar cells (OSCs). Two corresponding molecules with alkoxy side chains on BDT, DO1, and DO2 are also synthesized for comparison. The four compounds possess broad absorption covering the wavelength range 450鈥?40 nm and relatively lower HOMO energy levels from 鈭?.16 to about 鈭?.19 eV. D2 and DO2 with bithiophene 蟺-bridges demonstrate stronger absorbance and higher hole mobilities than the compounds with thiophene 蟺-bridges. The power conversion efficiency (PCE) values of the OSCs based on the organic compounds/PC₇₀BM (1.5:1, w/w) are 6.75% for D2, 5.67% for D1, 5.11% for DO2, and 4.15% for DO1. The results indicate that the molecules with thienyl conjugated side chains and bithiophene 蟺-bridges show better photovoltaic performance. The PCE of the D2-based OSC are among the highest values in the OSCs based on the solution-processed organic small molecules.

Keywords:

organic solar cells; D-A-D structured molecules with conjugated side chains; solution-processable organic photovoltaic materials