Low Bandgap Polymers Based on Regioregular Oligothiophenes Linked with Electron-Accepting Units
Extensive research has been conducted on organic solar cells (OSCs), because they are light weight, inexpensive to produce, and can potentially be used in flexible devices. OSCs based on a typical donor of regioregular poly(3-hexylthiophene) (P3HT) and acceptor of 6,6-phenyl-C61-butyric acid methyl ester (PCBM) have been reported to achieve a power conversion efficiency (PCE) of up to 4.5％. To further improve PCE, a common strategy relies on donor-acceptor (D-A) alternating copolymers, where the backbone is composed of an electron-rich donor unit and an electron-deficient acceptor unit, and the intramolecular charge transfer (ICT) results in a lower bandgap. Several OSCs based on these types of polymers have recently been reported to show PCEs of over 6％. However, there are several drawbacks to these copolymers. Although ICT shifts the absorption band to the longer wavelength region, the absorbance in the short wavelength range is generally weakened or even lost, owing to the large splitting of the absorption band. Moreover, D-A alternating copolymers with acceptor units having strong electron affinity in the backbone often show lower charge carrier mobility compared with highly crystalline semiconducting polymers, possibly due to the localized HOMO in the main chain, or less ordered interchain packing induced by the lower regularity of the polymer structures.
Luozheng ZHANG Yue ZHANG Keisuke TAJIMA Kazuhito HASHIMOTO
Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo
国际会议
天津
英文
49-50
2011-09-16（万方平台首次上网日期，不代表论文的发表时间）