Pyrazinoquinoxaline-Based Conjugated Copolymers with Coplanar Indolocarbazole Moieties Designed for Efficient Photovoltaic Applications
作者：Qiang Peng, Xiangju Liu, Yuancheng Qin, Mingjun Li, Jun Xu, Guanwen Fu and Liming Dai
關鍵字：Polymer solar cell
論文來源：期刊
具體來源：Journal of Materials Chemistry, 2011，21，7714-7722.
發表時間：2011年
A series of low band gap copolymers consisting of electron-accepting pyrazino[2,3-g]quinoxaline (PQx) and an electron-donating indolo[3,2-b]carbazole and thiophene units have been designed and synthesized by Stille coupling polymerization. Their optical and electrical properties could also be facilely fine-modulated for photovoltaic application by adjusting the donor/acceptor ratios. UV-vis measurements showed that increasing the content of PQx units led to enhanced absorption. The band gaps obtained from UV-vis spectra, CV scanning, and DFT modeling all indicated a narrowing band gap with increasing the PQx content in the copolymer structure. The photovoltaic solar cells (PSCs) based on these copolymers were fabricated and tested with a structure of ITO/PEDOT:PSS/copolymer:PCBM/Ca/Al under the illumination of AM 1.5G, 100 mW/cm2. The best performance was achieved using P3/[70]PCBM blend (1:3) with Jsc = 9.55 mA/cm2, Voc = 0.81 V, FF = 0.42, and PCE = 3.24%, which is the highest efficiency for the PQx and indolo[3,2-b]carbazole based devices. The present results also indicate that the efficient photovoltaic materials with suitable electronic and optical properties can be achieved by just fine-tuning the ratios of the strong electron-deficient accepters and large-π planar donors.