Effects of Biaxial Strain on the Optical and Electronic Properties of Monolayer PtS₂ with Sulfur Defects: A First‐Principles Study

This study investigates the electronic and optical properties of defective monolayer PtS 2 under biaxial strain based on density functional theory. Initially, the stability of models is demonstrated through calculations of phonon dispersion and molecular dynamics. The formation energies of three defect structures are discussed, proving that the single S defect is the most stable defect structure and possesses a direct bandgap different from the intrinsic model. The bandgap of this system decreases with increasing tensile strain and increases with increasing compressive strain. A lower bandgap than the nondefective state can be achieved when a 6% tensile strain is applied. For the defective system, the absorption and reflection coefficients in the low‐energy region gradually increase under tensile strain and exhibit a redshift. Under compressive strain, both coefficients gradually decrease and exhibit a blueshift. This article reveals the modulation effect of strain on the electronic properties of defective monolayer PtS 2 , which holds significant importance for the expansion of material functionalities and the optimization of device performance.