Color Tuning of Avobenzone Boron Difluoride as an Emitter to Achieve Full‐Color Emission

Organic light‐emitting diodes (OLEDs) displaying a wide range of emission colors with emission peaks from 450 to 665 nm using a single emitting material, avobenzone boron difluoride (AVB‐BF 2 ), are reported. Color tuning is achieved by controlling the aggregation of AVB‐BF 2 and the formation of a “triadic” exciplex of an AVB‐BF 2 dimer and a host molecule. Various electroluminescent devices containing AVB‐BF 2 cover the whole visible light spectrum and a white‐emitting device with CIE coordinates of (0.35, 0.37) is obtained with a single emitting material in a single emissive layer. Furthermore, an exceptionally high external quantum efficiency of nearly 13% is achieved for a green‐emitting OLED because AVB‐BF 2 exhibits thermally activated delayed fluorescence by forming the exciplex.