Perovskite CsPbBr3 decorating PbS nanocrystals for efficient near-infrared light-emitting diodes: A first-principles study

Abstract

Assembling near-infrared emitting materials with another semiconductor material is a promising approach to improve the performance of NIR light-emitting devices. Here we performed a computational and theoretical study on feasibility of improving performance PbS based near-infrared emitting devices by perovskite CsPbBr3 decorating. Physical mechanism of improved light-emitting efficiency is revealed by electronic structure calculations. The type-I band alignment of CsPbBr3/PbS interface facilitates the transferring of electrons and holes in CsPbBr3 quantum dots to PbS active material, which is confirmed by the charge density difference results. The rather small lattice mismatch and analogous octahedral framework ensure an almost perfect contact and little density of gap states at CsPbBr3/PbS interface. The improved light absorption in CsPbBr3/PbS heterostructured nanocrystals ensures an enhanced near-infrared light-emitting in PbS. Our work provides a theoretical understanding on the physical mechanism of improved near-infrared emitting performance in CsPbBr3 decorated PbS based light-emitting devices, and suggests a promising route to design near-infrared emitting devices with high performance.