Control of the stability, transport, and confinement of charge carriers (electrons and holes) at interfaces is a key requirement to realize robust halide perovskite devices. The PbS-CsPbBr3 interface is atomically matched with low lattice strain, opening the potential for epitaxial growth. We assess the atomic nature of the interface using first-principles density functional theory calculations to identify (1) the thermodynamically stable (100) surface termination of the halide perovskite; (2) the most favorable (100)|(100) contact geometry; (3) the strong interfacial chemical bonding between PbS and CsPbBr3; (4) the type I (straddling) band alignment that enables electron and hole confinement in the lead sulfide layer. The combination of metal halide perovskites and IV-VI semiconductors represents an important platform for probing interfacial chemical processes and realizing new functionality.
Bibliographical noteFunding Information:
We thank A. Soon for fruitful discussions. The work at ICL was supported by the EPSRC (Grant No. EP/K016288/1 and EP/ M009580/1) and the ERC (Grant No. 277757). A.W. is supported by a Royal Society University Research Fellowship. Via our membership of the U.K.’s HEC Materials Chemistry Consortium, which is funded by EPSRC (EP/L000202), this work used the ARCHER UK National Supercomputing Service (http://www.archer.ac.uk).
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films