Molecular Design of High-performance Wide-bandgap Acceptor Enables Versatile Organic Photovoltaic Applications

Abstract

As the exploration of organic photovoltaic (OPV) applications deepens, wide-bandgap (WBG) OPV cells exhibit great potential in various novel applications. However, advancements in high-performance WBG acceptors are relatively slow. Here, we designed and synthesized a WBG acceptor, FPCC-Br, by reducing the overlap of the highest occupied molecular orbital and the lowest unoccupied molecular orbital distributions. Due to the simplified synthetic route and high synthesis yield, FPCC-based acceptors exhibit the lowest raw material cost among all WBG acceptors. Benefitting from its excellent charge transfer and exciton dissociation ability, PBQx-TF:FPCC-Br-based cell exhibits a power conversion efficiency (PCE) of 13.6%, which is the champion efficiency for OPV cells with bandgap below 720 nm. Besides, the PBQx-TF:eC9-2Cl:FPCC-Br-based ternary cell exhibits an impressive PCE of 19.3%. When placed under a light-emitting diode lamp with an illumination of 1000 lux, the PBQx-TF:FPCC-Br-based cells achieve an impressive PCE of 29.3%. Then, the PBQx-TF:FPCC-Br-based cell was employed as the front cell in a tandem cell, realizing a noteworthy PCE of 20.1%. Besides, the cells connected in series are employed to directly produce hydrogen through underwater photovoltaic electrolysis (UPE), achieving a solar-to-hydrogen efficiency of 6.91%. Moreover, the cells demonstrate remarkable thermal stability at 80°C, indicating its feasibility for application in UPE. Our work provides a viable molecular design approach for WBG acceptors and underscores the promising prospects of WBG OPV cells for versatile applications.