The exploration of acceptor ratio in thermally activated delayed fluorescent donor for the effect on exciplex OLED

The effect of PO-T2T acceptor ratio in thermally activated delayed fluorescent donor of DMAC-DPS on exciplex organic light-emitting diodes (OLED) performance is explored herein. As the ratio decrease of PO-T2T acceptor, we found an obvious blue shift of electroluminescence (EL) spectra from 536 nm to 496 nm, while the EL efficiency maintain a high level with maximum current efficiency of 25.7–38.1 cd/A, power efficiency of 24.2–39.5 l m/W and external quantum efficiency (EQE) of 10.4–12.1%, respectively. That means a wide spectral move range of 40 nm without damaging device EQE in exciplex OLED could be realized. The strong interaction between exciplex induced from charge separation is responsible for the blue shift as acceptor ratio reduce.