Two-Dimensional Perovskite/HfS₂ van der Waals Heterostructure as an Absorber Material for Photovoltaic Applications

Van der Waals (vdW) heterostructures of perovskites and transition metal dichalcogenides (TMDCs) have attracted increased interest owing to their extraordinary optoelectronic properties and encouraging applications. Two-dimensional (2D) TMDCs, i.e., hafnium disulfide (HfS2), are also interesting because of their unique optoelectronic properties. Therefore, the combination of these different types of materials is very smart in terms of the fundamental science of interface interaction, as well as for the understanding of ultrathin optoelectronic devices with superior performance. Here, we have systematically modeled the 2D CH3NH3PbI3/HfS2 vdW heterostructure by using first-principles calculations. The substituted interface has enhanced visible-light sensitivity and photoelectrocatalytic activity by reducing the transition energies. The interfacial interaction of both materials effectively tunes the band gap of the interface; therefore, it would significantly improve the photoreactivity for solar cell applications. Due to the presence of small effective masses of electrons-holes, high optical absorption on the order of 10(5) and high spectroscopic limited maximum efficiency of 28.45% in the CH3NH3PbI3 /HIS2 vdW heterostructure will be better candidates in the field of absorber materials. The considered systems are expected to be more efficient in separating the photogenerated electrons-holes and active in the visible spectrum. These theoretical results suggest that the CH3NH3PbI3/HfS2 vdW heterostructure may lead to many novel applications in efficient light-absorbing materials for photovoltaic applications.