Unsubstituted Benzodithiophene-Based Conjugated Polymers for High-Performance Organic Field-Effect Transistors and Organic Solar Cells

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• 作者：Weichao Chen ; Manjun Xiao ; Liangliang Han ; Jidong Zhang ; Huanxiang Jiang ; Chuantao Gu ; Wenfei Shen ; Renqiang Yang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：August 3, 2016
• 年：2016
• 卷：8
• 期：30
• 页码：19665-19671
• 全文大小：387K
• 年卷期：0
• ISSN：1944-8252

文摘

Unsubstituted benzo[1,2-b:4,5-b′]dithiophene (BDT) was used to construct a high-performance conjugated polymer with 5,6-difluoro-4,7-bis[4-(2-octyldodecyl)thiophene-2-yl]benzo[c][1,2,5] thiadiazole (DTFFBT), named PBDT-DTFFBT. The polymer shows the low-lying highest occupied molecular orbital (HOMO) energy level (−5.40 eV) and a broad absorption spectra with strong vibronic absorption peak. Pure polymer films exhibit good crystallinity and edge-on orientation, partially attributed to the BDT units without any side chains, and as a result, the corresponding thin-film transistor showed excellent hole mobility over 1 cm² V^–1 s^–1. Interestingly, a well-distributed nanofibrillar polymer aggregation with face-on orientation was obviously formed when blending with PC₇₁BM, which was in favor of the charge transportation. Consequently, the bulk heterojunction polymer solar cells based on the blends showed high power conversion efficiency of 9.29% with large short-current density (14.56 mA cm^–2) and high fill factor (0.751) without any process additives or thermal annealing.