The interfacial charge transfer and band edge alignment coupled with strong visible light absorption in the heterostructure is a fundamental tuning criterion for both photovoltaic and photocatalytic efficiencies. We have envisaged how both criteria evolve under the influence of electric field and temperature in a novel van der Waals (VdW) heterostructure composed of the all-inorganic perovskite CsSnI3 and the two-dimensional (2D) MXene Zr2CO2. Using density functional theory (DFT), we have systematically investigated the structural, electronic, and optical responses of the CsSnI3−Zr2CO2 heterostructure under these external perturbations. Our results reveal that controlled tuning of thermal and electric field conditions effectively modulates the band alignment, enabling enhanced charge separation and extraction, crucial for optimizing photovoltaic performance. Beyond photovoltaics, we demonstrate that the synergistic influence of electric field and temperature promotes favorable band-edge positions relative to water redox potentials, alongside strong visible light absorption, leading to a theoretical solar-to-hydrogen (STH) conversion efficiency approaching 30%. These insights underscore the promise of 2D perovskite-MXene VdW heterostructures as multifunctional materials for efficient solar energy harvesting and conversion.
Arijeet Sarangi