Highly efficient two-dimensional conjugated benzodithiophene-based photovoltaic polymers

Abstract

In order to improve the photovoltaic properties of polymer solar cells (PSC), varieties of donor and acceptor units were designed and synthesized to construct the highly efficient conjugated polymers. Recent years, materials based on benzo [1.2-b:4,5-b ¢ ]dithiophene (BDT) units have showed promising applications in the field of organic photovoltaics for its excellent properties. As compared to BDT-based polymers with flexible side chains, polymers based on two-dimensional conjugated BDT (2D-BDT) usually had better thermal stability, slightly red-shifted of absorption spectra, lower HOMO levels, higher hole mobility and consequently improved photovoltaic properties. By using novel 2D-BDT-based polymers, the power conversion efficiency (PCE) of the PSC devices has been boosted to over 10%. In this article, we first briefly introduce the synthesis methods of 2D-BDT unit, and then focus our attention to summarize the numerous of 2D-BDT-based polymers and their applications in highly efficient PSC devices.