Strain Engineering of the Pentagonal PtSiTe Monolayer for Enhanced Photovoltaic and Thermoelectric Efficiency: A First-Principles Investigation

Recently, there has been a significant interest in the theoretical exploration of stable two-dimensional (2D) polar transition metal monolayers, which exhibit intriguing piezoelectric and photovoltaic properties. This has not only led to an expansion of the 2D materials family but also generated enthusiasm for the possibility of manipulating various properties without altering the chemical composition or introducing defects. In this first-principles study, we investigated the impact of strain on the optoelectronic and thermoelectric properties of the pentagonal PtSiTe monolayer. Using density functional theory calculations, we explored the electronic band structure, optical properties, and thermoelectric characteristics of PtSiTe under varying strain conditions. Our results reveal that the application of tensile strain significantly enhances the band structure, leading to an intriguing indirect–direct transition of the band gap, with a transformation occurring at 8% strain. This strain-induced modification differentiates the material from its strain-free counterpart, resulting in a band gap variation of 10%. Additionally, we analyze the thermoelectric response and photovoltaic properties of the strained monolayer. The efficiency of the solar cell is improved by about 27% for the strained system compared to that of the unstrained one. Furthermore, we find that the figure of merit of ZT increases by approximately three times for the strained system, indicating a significant enhancement in the thermoelectric performance. Our findings shed light on the potential of strain engineering as a promising tool to tune the optoelectronic and thermoelectric behavior of 2D materials, with implications for future device applications. The study contributes to the broader exploration of stable 2D polar transition metal monolayers, indicating the versatility and potential of 2D solar cell materials in advanced photovoltaic and thermoelectric technologies.