Engineering of interface exciplex system for highly efficient white organic light-emitting diodes based on single-emission-layer architecture

Highly efficient white organic light-emitting diodes (WOLEDs) with low turn-on voltages and efficiency roll-offs actualized by simplified structure are still a great challenging subject. Herein, the interface exciplex structure is manipulated to achieve high-efficiency phosphorescent WOLEDs with single-emitting-layer for the first time. The key to our strategy is the enhancement of Förster energy transfer from interface exciplex to guest and well restriction of exciton recombination region. By incorporating complementary emitters into acceptor layer, color-stable WOLEDs with low turn-on voltages are demonstrated. The maximum efficiencies of 81.1 cd A−1 and 101.9 lm W−1 are realized in the optimized device with suppressed roll-off. These results provide an effective approach to construct high performance WOLEDs based on simplified architecture.