Synthesis and characterization of new asymmetric thieno[3,4-b]pyrazine-based D−π−A−A type small molecular donors with near-infrared absorption and their photovoltaic applications - Chou, Shu-Hua; Chen, Hsieh-Chih; Wang, Chun-Kai; Chung, Chin-Lung; Hung, Chieh-Ming; Hsu, Jung-Chun; Wong, Ken-Tsung (Organic electronics, 2019)