Resonance hosts for high efficiency solution-processed blue and white electrophosphorescent devices

The exploration of high-performance solution-processible host materials for blue and white electrophosphorescent devices is a key and fundamental challenge in the ongoing development of organic semiconductors. Herein, two solution-processible resonance host materials with self-adaptive characteristics are delicately designed and constructed. Because of the dynamic tautomerization upon resonance variation, these smart hosts show self-adaptive and selectively enhanced charge carrier flux at high triplet energy levels. Conferred by the resonance molecules, solution-processed blue and white devices exhibit excellent maximum current efficiencies (CEs) of 29.8 and 57.3 cd A⁻¹, and external quantum efficiencies (EQEs) up to 14.5% and 23.5%, respectively. Our works highlight the significant progress of the solution-processed phosphorescent organic light-emitting diodes (PhOLEDs) using resonance host molecules, potentially furnishing a leap forward in constructing advanced organic semiconductors for next-generation optoelectronic devices.[Figure not available: see fulltext.].