A computational study of electrical contacts to all-inorganic perovskite CsPbBr₃

All-inorganic halide perovskites are promising candidates for optoelectronic devices due to their excellent physicochemical properties and better thermal stability than their hybrid counterparts. The electrical contact to perovskite plays a crucial role in determining the device's performance. This paper investigated the contacts of two types of CsPbBr₃surface to a series of metals (Pd, In, Pb, Zr, Ti, Zn, graphene, and Ti₃C₂) through first-principles calculations. On the PbBr₂-terminated surface, all the studied metals form Schottky contacts with minimum barriers ranging from 0.63 to 0.97 eV. On the CsBr-terminated surface, Ti and Ti₃C₂forms n-type Ohmic contacts while others form Schottky contacts with minimum barriers ranging from 0.25 to 0.97 eV. Ti₃C₂, considering the small Schottky barrier, large tunneling barrier, and high electronic localization function, is found to be proper ohmic metal contacts with the CsBr-terminated surface. In addition, a -16.4% to 15.1% change in the size of the CsPbBr₃band gap is found because of the interfacial interaction. The Fermi pinning factor of the CsPbBr₃-metal contact is estimated via a modified method considering the gap change, and that of the PbBr₂-terminated one is slightly larger than that of the CsBr-terminated one, indicating a more flexible Schottky barrier in the former through changing the metal work function. This work presents a comprehensive understanding of metal contacts to all-inorganic perovskite CsPbBr₃and offers theoretical guidance for preparing high-performance inorganic perovskite photoelectric devices.