Synthesis and Characterization of New Dihydroindolo[3,2-6]indoIe and 5,6-Bis(octyloxy)-4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole-Based Polymer for Bulk Heterojunction Polymer Solar Cells

摘要

We have designed and developed a new ladder type tetrafused π-conjugated building block such as dihydroindolo[3,2-b]indole (DINT) and investigated its role as an electron rich unit. The photovoltaic properties of a new semiconducting π-conjugated polymer, poly[[5,10-bisocryl-5,10-dmydroindolo[3,2-b]indole-[5,6-bis(octyloxy)-4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole]], represented by PDTNI-OBTC8 are described. The new polymer PDINI-OBTC8 was synthesized in donor-acceptor (D-A) fashion, where fused π-conjugated tetracyclic DINI, and 5,6-bis(octyloxy)-4,7-di(thiophen-2-yl) benzo[c][1,2,5]thiadiazole (OBTC8) were employed as electron rich (donor) and electron deficient (acceptor) moieties, respectively. The conventional bulk heterojunction (BHJ) device structure ITO/PEDOT:PSS/PDTNI-OBTC8:PCB_(71)M/LiF/Al was utilized to fabricate polymer solar cells (PSCs), which comprises the blend of PD1NI-OBTC8 and [6,6]-phenyl-C_(71)-butyric acid methyl ester (PC71BM) in BHJ network. A BHJ PSC that contain PDTNI-OBTC8 delivered power conversion efficiency (PCE) value of 1.68% with 1 vol% of 1,8-diidooctane (DIO) under the illumination of A.M1.5G100mW/cm~2.