Bithienopyrroledione-Based Copolymers, Versatile Semiconductors for Balanced Ambipolar Thin-Film Transistors and Organic Solar Cells with Voc > 1 V
Advanced Functional Materials, 27 (4):
n/a--n/a (2017)DOI: 10.1002/adfm.201604286
Abstract
Conjugated polymer semiconductors P1 and P2 with bithienopyrroledione (bi-TPD) as acceptor unit are synthesized. Their transistor and photovoltaic performances are investigated. Both polymers display high and balanced ambipolar transport behaviors in thin-film transistors. P1-based devices show an electron mobility of 1.02 cm2 V−1 s−1 and a hole mobility of 0.33 cm2 V−1 s−1, one of the highest performance reported for ambipolar polymer transistors. The electron and hole mobilities of P2 transistors are 0.36 and 0.16 cm2 V−1 s−1, respectively. The solar cells with PC71BM as the electron acceptor and P1/P2 as the donor exhibit a high Voc about 1.0 V, and a power conversion efficiency of 6.46% is observed for P1-based devices without any additives and/or post treatment. The high performance of P1 and P2 is attributed to their crystalline films and short π–π stacking distance (<3.5 Å). These results demonstrate (1) bi-TPD is an excellent versatile electron-deficient unit for polymer semiconductors and (2) bi-TPD-based polymer semiconductors have potential applications in organic transistors and organic solar cells.