Despite the high performance of OLEDs consisting of host–guest blend systems in the emissive layer, OLEDs containing a single molecule as an emitter in the emissive layer (i.e. non-doped OLEDs) have significant advantages including easy fabrication procedures and enhanced device stability.

Thermally activated delayed fluorescence materials exhibited outstanding external quantum efficiencies in OLEDs along with good CIE color coordinates and improved device stabilities. Hence these are most promising for commercialization of OLEDs.

Three new color‐tunable (deep‐blue to sky‐blue) and solution‐processable emitters—9′‐(2,12‐di‐tert‐butyl‐5,9‐dioxa‐13b‐boranaphtho[3,2,1‐de]anthracen‐7‐yl)‐9′H‐9,3′:6′,9″‐tercarbazole (TB‐3Cz), 9′‐(2,12‐di‐tert‐butyl‐5,9‐dioxa‐13b‐boranaphtho[3,2,1‐de]anthracen‐7‐yl)‐9,9″‐diphenyl‐9H,9′H,9″H‐3,3′:6′,3″‐tercarbazole (TB‐P3Cz), and 9‐(2,12‐di‐tert‐butyl‐5,9‐dioxa‐13b‐boranaphtho[3,2,1‐de]anthracen‐7‐yl)‐N3,N3,N6,N6‐tetraphenyl‐9H‐carbazole‐3,6‐diamine (TB‐DACz)—are demonstrated, which are cleverly designed and synthesized by appending a boron‐fused entity as an electron acceptor to different electron‐rich entities containing carbazole derivatives as donors. The thermal, photophysical, electrochemical, and electroluminescent characteristics of all the new materials are extensively investigated. Comprehensive photophysical investigations reveal that these emitters exhibit not only thermally activated delayed fluorescence (TADF) but also aggregation‐induced emission (AIE) properties. Consequently, solution‐processable organic light‐emitting diodes (OLEDs) fabricated using these new materials as nondoped emitters in the emissive layer exhibit a maximum external quantum efficiency (EQE) and Commission Internationale de l'Éclairage (CIE) color coordinates of 9.90% and (0.17, 0.07), respectively, for TB‐3Cz; 6.13% and (0.15, 0.08), respectively, for TB‐P3Cz; and 6.04% and (0.18, 0.40), respectively, for TB‐DACz. As far as it is known, the performance and ultrahigh color purity satisfying the deep‐blue CIE coordinates of the National Television System Committee (NTSC) for TB‐3Cz and TB‐P3Cz are the highest reported thus far for nondoped solution‐processable TADF emitters, indicating the great potential of these materials as deep‐blue luminogens in OLED applications.

Efficient electron transporting blue emitting materials obtained from excimer emission assisted by thermally activated delayed fluorescence.

A new solution-processable polymeric emitter containing non-conjugated cyclohexane units was developed for high-performing TADF-OLEDs.