WONDER · Low-Bandgap Fused Ring Electron Acceptors towards High-Efficiency Organic Solar Cells

Organic solar cells (OSCs) based on fused ring electron acceptors (FREAs) attract significant attention recently and exhibit great potential to achieve high efficiency, due to the FREA’s merits of high absorption coefficients in visible region, easily tunable energy levels, relatively high electron mobility, and proper miscibility with donors for fine phase separation. Despite of the great advance in FREAs over the past few years, the power conversion efficiency (PCE) of FREA based OSCs is still lower than those of other solar cells so far. It is limited by two major problems: large bandgap of FREAs and large energy loss (Eloss) in devices.In this project, I aim to address these issues and develop high-efficiency OSCs from three aspects: 1) to develop novel FREAs with low bandgap, matching energy levels and high electron mobility via designing novel large fused ring donor units, 2) To reduce Eloss via adjusting and matching the energy levels of polymer donors and FREAs for high-efficiency OSCs, 3) to formulate key rules of designing FREAs to achieve low Eloss with high short-circuit current density (JSC) and fill factor (FF) via exploring the relationship between Eloss in OSCs and the intrinsic properties of FREAs. The expected outcomes of this project include new FREA materials and high-efficiency OSCs, as well as fundamental knowledge concerning Eloss in OSCs. In addition to the scientific achievements, the fellow will obtain new interdisciplinary knowledge and skills, and achieve professional maturity by training during the project. Successful implementation of this project will also promote the international competitiveness of the host organization in OSCs. Potential commercialization of the new FREA materials and OSC products will contribute to economic growth and afford new job opportunities for the European society.