Two-dimensional MXO/MoX₂ (M = Hf, Ti and X = S, Se) van der Waals heterostructure: a promising photovoltaic material

Nanoscale materials with multifunctional properties are necessary for the quick development of high-performance devices for a wide range of applications, hence theoretical research into new two-dimensional (2D) materials is encouraged. 2D materials have a distinct crystalline structure that leads to intriguing occurrences. Stacking diverse two-dimensional (2D) materials has shown to be an efficient way for producing high-performance semiconductor materials. We explored a 2D nanomaterial family, an MXO/MoX₂ heterostructure (M = Hf, Ti and X = S, Se), for their various applications using first-principles calculations. We discovered that all of the heterostructure materials utilized are direct band gap semiconductors with band gaps ranging from 1.0 to 2.0 eV, with the exception of hexagonal HfSeO/MoSe₂, which has a band gap of 0.525 eV. The influence of strain on the band gap of this HfSeO/MoSe₂ material was investigated. In the visible range, we obtained promising optical responses with a high-power conversion efficiency. With fill factors of 0.5, MXO/MoX₂ photovoltaic cells showed great PCE of up to 17.8%. The tunable electronic characteristics of these two-dimensional materials would aid in the development of energy conversion devices. According to our findings, the 2D Janus heterostructure of MXO/MoX₂ (M = Hf, Ti and X = S, Se) material is an excellent choice for photovoltaic solar cells.