Strain-Tunable Photovoltaic Properties of Non-Metal-Doped PtS2 under Biaxial Deformation

This study conducts a comprehensive first-principles density functional theory analysis on pristine PtS ₂ monolayers and those doped with O, Se, Te, Si, P, and Cl atoms. Geometry optimization reveals that different doping induces ordered changes in bond lengths and lattice parameters. Electronic structure calculations indicate that doping effectively tunes the bandgap from semiconducting to near-metallic states, inducing pronounced orbital hybridization at the Fermi level. Optical property analysis (real and imaginary dielectric functions, absorption coefficients, and reflectivity) reveals the differences in the response of doped systems in the UV, VIS, and NIR wavelength bands. Furthermore, the O and P-doped systems were investigated systematically. The band gap and main absorption/reflection peaks undergo reversible redshift and blueshift when bi-directional strain is applied to the O and P doped systems. The study provides a comprehensive and compact theoretical basis for the applications of tunable photovoltaic devices, IR detectors, and flexible strain sensors based on PtS ₂ .