Computational insight on CsPbX3 (X = Cl, Br, I) and two-dimensional MYZ (M = Mo, W; YZ = Se, S) heterostructures

Since two-dimensional transition metal dichalcogenides (TMDs) and halide-based perovskites display superior optoelectronic properties, interfacing of TMDs and Janus materials with halide perovskites may improve the performance of photovoltaics and photodetectors. Using first-principles computations, this work thoroughly analyzes the electronic as well as optical properties of 2D CsPbX3/MYZ composites (X = Cl, Br, I; M = Mo, W; and YZ = S, Se). The findings demonstrate that the interaction of CsPbX3 with the MYZ surface enables bandgap tuning, and interfacial electric field causing spatial charge separation, and results in small values of effective mass. In CsPbI3/MYZ and CsPbX3/MoS2 hybrids, type-II band alignment ensures efficient carrier separation, thus lowering the recombination. While other heterostructures exhibited a type-I band alignment, suitable for long-lifetime photodetectors. The HSE06 bandgap for all heterostructures resides within desired range of 1.23–3 eV. The low tunnel barrier heights also favor high circuit voltages, suitable for photovoltaic applications. Next, remarkable absorption in hybrids promises their suitability for optoelectronics and radiation detection. Incorporation of water redox levels further validates their capability as photocatalysts driving overall water-splitting photocatalysis.