摘要
Organic light-emitting diodes (OLEDs) with high external quantum efficiency and long operational lifetimes that have been solution-processed are still in their infancy. In this context, two new thermally activated delayed fluorescent (TADF) emitters, KCPOZ and KCPTZ, are designed using a new design strategy consisting of an interlocked unsymmetrical dual acceptor core for solution-processed yellow OLEDs. Unsymmetrical and twisted molecular structure aided twisted intramolecular charge transfer in their films. Narrow ΔE ST in both the emitters enabled efficient triplet exciton population and fast reverse intersystem crossing to manufacture high-efficiency OLED devices. A doped (5% in CBP) OLED device based on KCPOZ showed the best performance between both. The 5.0 wt % KCPOZ-doped device exhibited a PEmax of 85.6 lm/W, CEmax of 95.2 cd/A, EQEmax of 31.5%, and L max of 18,240 cd/m2. Both emitters were also employed as sensitizers for TBRb, an orange TADF emitter, to improve the orange device performance. EQEmax increased from 5% to 20 and 18.0% when KCPOZ and KCPTZ concentrations climbed from 0 to 10%. At 100 cd/m2, the KCPOZ-based device had an estimated half-lifetime of 19,844 h, while the KCPTZ-based device had a lifetime of 10,550 h. This work demonstrates using unconventional ways to design molecular core structures integrated with appropriate donors to enable high efficiency in the OLED device with a longer lifetime.