Developing nanoscale morphology for high-performance organic bulk-heterojunction at a large area

Recently, organic photovoltaics show high efficiency over 20% in a cell, which showing the great potential of organic photovoltaic technology as a futuristic energy source. It is important to develop organic materials and printing technology to form high performance p-n junction at a large area. We have tried to understand an intrinsic material property of dielectric nature of the organic blends and pursue developing dielectric additives which can enhance charge generation of active materials at a large bulk-heterojunction (BHJ) area. In this presentation, we will introduce our recent research works about comprehensive understanding about the influences of chemical structures of organic materials on their excitonic properties and improvement of charge generation; in particular, appropriate incorporation of dielectric additives enables evolution of homogeneous morphology over large areas irrespective of surface energy of the electron-transporting layer. As a result, organic photovoltaic devices using binary D18:PM6 donors achieved efficiency of 17.44% at active area of 1 cm2 and the corresponding module showed 16.27% efficiency.