Molecular Design toward Efficient Polymer Solar Cells with High Polymer Content

ABSTRACT: A novel polythiophene derivative, PBT1, was designed, synthesized, and applied in polymer solar cells (PSCs). This work provides a successful example of using molecular structure as a tool to realize optimal photovoltaic performance with high polymer content, thus enabling the realization of efficient photoabsorption in very thin films. As a result, an efficiency of 6.88 % was recorded in a PSC with a 75 nm active layer. Polymer solar cells (PSCs) with bulk heterojunction (BHJ)structure are particularly attractive because of their ease of processing, large area with mechanical flexibility, and potential low-cost production.1 The typical BHJ layer in PSCs is composed of a blend of two ingredients, a polymer as the electron donor and a polymer or small-molecule compound as the electron acceptor. Great effort has been devoted to modulating the properties of the BHJ layers, which strongl