1, Nanjing Tech University, Nanjing, , China
Solution-processed light-emitting diodes (LEDs) are attractive for applications in low-cost, large-area lighting sources and displays. Organometal halide perovskites can be processed from solutions at low temperatures to form crystalline direct-bandgap semiconductors with intriguing optoelectronic properties. However, their electroluminescence (EL) efficiencies are limited by either exciton quenching in the two-dimensional perovskites or imperfect film morphologies in the three-dimensional perovskites. I will present that strikingly high-efficiency, room-temperature EL can be achieved from solution-processed hybrid perovskite films consisting of self-organized multiple quantum wells (MQWs) with an energy cascade. The perovskite MQW films deposited at low temperatures exhibit uniform morphology and high photoluminescence efficiencies resulting from efficient cascade energy transfer between the quantum wells. LEDs based on perovskite MQWs show peak external quantum efficiency (EQE) up to 11.7% with good operation stability. Our study shows that perovskite MQWs are promising as a new class of solution-processed emitters for LEDs.