High-power-efficiency and ultra-long-lifetime white OLEDs empowered by robust blue multi-resonance TADF emitters

Abstract

White organic light-emitting diodes (WOLEDs) show very promising as next-generation light-sources, but achieving high power efficiency (PE) and long operational lifetime remains challenging because of the lack of stable blue emitters that can harvest all triplet (T₁) excitons for light emission. Herein, we propose integrating stable azure multi-resonance thermally activated delayed fluorescent (MR-TADF) emitters into tri-color hybrid WOLEDs to tackle these issues. By meticulously selecting MR-TADF emitters and precisely tuning the exciton recombination zone, the optimized tri-color devices based on BCzBN-3B achieve color-stable white light emission with maximum external quantum efficiency (EQE_max) and maximum PE (PE_max) of 34.4% and 101.8 lm W⁻¹, respectively. Furthermore, the LT₉₀, defined as the time for the luminance to drop to 90% of its initial value at 1000 cd m⁻², reaches 761 h. In addition, a hybrid WOLED with deep blue emitter developed using our strategy achieves a high color rendering index of 88 and an EQE_max of 30.6%, further demonstrating the versatility and effectiveness of our approach. The record-breaking efficiency and ultra-long lifetime underscore the success of hybrid white-light devices by incorporating robust blue MR-TADF emitters. These advancements open new avenues for commercialization of hybrid WOLEDs, presenting promising solutions for energy-efficient lighting and display technologies.