Low turn-on voltage CsPbBr3 perovskite light-emitting diodes with regrowth crystal MAPbBr3 hole transport layer

This work reports the effect of a MAPbBr3 layer in CsPbBr3 perovskite light-emitting diodes (PeLEDs). The MAPbBr3 layer employed MAPbBr3 powder as the evaporation source, which was obtained from using MAPbBr3 bulk crystals prepared by the inverse temperature crystallization method. The devices exhibited the best quality and performance when a 20-nm-thick MAPbBr3 layer was used as the nucleation and hole transport layer. The rc-MAPbBr3/CsPbBr3 structure apparently boosted the carrier lifetime such that the injection holes and electrons quickly recombine and then transfer into photons and emissions. The champion luminescence and external quantum efficiency were 21,850 cd/m2 at a bias of 7.0 V and 1.18% at a bias of 6.5 V, respectively.