A pathway to coexistence of electroluminescence and photovoltaic conversion in organic devices.

Achieving both high electroluminescence (EL) efficiency and power conversion efficiency (PCE) in a single organic device has long been considered difficult, since the design principles optimising one often compromise the other. In this study, we present a strategy employing multiple-resonance thermally activated delayed fluorescence materials with strong absorption and high emission efficiency, enabling coexistence of high EL and photovoltaic (PV) efficiencies. By precisely controlling charge-transfer states at donor/acceptor interfaces, we successfully achieve full-spectrum visible EL while maintaining efficient charge generation essential for PV operation. The optimised multifunctional devices exhibit emission colours ranging from blue to red, as well as white, with the green- and orange-light-emitting devices achieving an external quantum efficiency of EL exceeding 8.5% and a PCE of about 0.5%. These findings not only mitigate conventional efficiency trade-offs in organic devices but also open future avenues for emerging applications, including self-powered displays and lighting, potentially advancing optoelectronic technologies.