The formation of perovskite multiple quantum well structures for high performance light-emitting diodes

Recent works showed that high efficient perovskite light-emitting diodes can be achieved from solution-processed, self-organized multiple quantum wells (MQWs) with an energy cascade. We investigate how the mixing of QWs with different band gaps can affect the perovskite LED device performance. We find that the annealing process can significantly affect the constitution of the MQWs films, where the dominant phase can evolve from large band gap QWs to small band gap QWs. The optimal constitution for LED application lies in a transition point of small- n QWs dominant phase to large- n QWs dominant phase, when the MQW film presents highest photoluminescence while still remains uniform film morphology.