Synthesis and Characterization of Semiconducting Conjugated Polymers Containing 2,7-Dibenzosilole for High Open-Circuit Voltage in Organic Solar Cells

Abstract

We synthesized a donor-acceptor (D–A) type conjugated polymer for organic solar cells composed of 2,7-dibenzosilole (DBS) as an electron-rich unit and benzo[c][1,2,5]oxadiazole (BO) as an electron-deficient unit by Suzuki coupling. We also synthesized dithienosilole based D–A type alternating copolymer, PDTSDTBO as reference. The HOMO energy levels of PDBSDTBO and PDTSDTBO were -5.52 eV and -5.23 eV, respectively.The solar cell device fabricated by blending with PDBSDTBO and PC71BM as the active layer has higher VOC than that of the PDTSDTBO-based device, mainly due to the deeper HOMO energy level. The device fabricated with PDBSDTBO and PC71BM exhibits a power conversion efficiency (PCE) of 2.34%, which is higher than that of PDTSDTBO-based device.