High-performance color-tunable organic light-emitting diodes based on an exciplex-forming co-host

Color-tunable organic light-emitting diodes (OLEDs) have great potential for use in information security, smart lighting, and wearable healthcare. However, the performance of color-tunable OLEDs is currently far from meeting practical requirements. Here we present high-performance color-tunable OLEDs based on a novel, to the best of our knowledge, exciplex-forming co-host. The exciplex-forming co-host consists of the donor FSF4A and the acceptor B3PYMPM. High-performance color-tunable OLEDs have been demonstrated by combining an orange-doped emitting layer (EML) with a blue ultrathin or doped EML. The device with a blue ultrathin EML demonstrates extremely wide correlated color temperature (CCT) span of 11,411 K, which is attributed to the movement of the main exciton recombination zone and the exciton quenching effect in the blue ultrathin EML. The device with a blue-doped EML delivers a sunlight-style emission with a maximum power efficiency of 57.3 lm/W and achieves CCT span from 3451 K to 8073 K. It is expected that our work paves the way for fabricating high-performance color-tunable OLEDs for smart lighting applications.