Insight into the interface engineering between methylammonium lead halide perovskites and gallium oxide: a first-principles approach

Interface engineering of the organo-lead halide perovskite devices has shown the potential to improve their efficiency and stability. In this study, the atomic, electronic, optical and transport characteristics of MAPbI3/Ga2O3 and MAPbCl3/Ga2O3 interfaces were investigated by using first-principles calculations. Eight different interfacial models were established and the interfacial properties were discussed. The results show that the PbI/O configuration exhibits the largest bonding strength out of all eight interfacial configurations. Owing to the larger interfacial interaction, the charge transfer at the PbI/O interface is significantly more than that at the other interfaces. The analysis of absorption spectra indicates that the Ga-terminated perovskite/Ga2O3 heterostructures are expected to have great potential for efficient optoelectronic applications. The analysis of transmission spectra shows that the MA/O configurations with more transmission peaks near the Fermi level exhibit lower resistance compared to others. The results of our study could help understand the interfacial engineering mechanism between perovskite and Ga2O3. DFT coupled with NEGF calculations provide atomic insights into the interactions of MAPbCl3/Ga2O3 and MAPbI3/Ga2O3 heterostructures.