Electronic and optical properties of a novel two-dimensional semiconductor material TlPtS: a first-principles study.

Two-dimensional (2D) materials have attracted widespread attention due to their unique physical and chemical properties. Here, by using density functional theory calculations, we suggest a novel 2D TlPtS material whose layered bulk counterpart was synthesized in 1973. Theoretical calculation results indicate that the exfoliating energy of monolayer and bilayer TlPtS is 34.96 meV Å and 36.03 meV Å. We systematically studied the electronic and optical properties of monolayer and bilayer TlPtS, and revealed that they are indirect band gap semiconductors with band gaps of 2.26 eV and 2.10 eV, respectively. Monolayer and bilayer TlPtS exhibit superior carrier mobility (901.63 cm V s and 13635.04 cm V s for electron mobility of the monolayer and bilayer, respectively) and photocatalytic performance (as high as 1 × 10 light absorption coefficient in the visible light region). Interestingly, we find that monolayer TlPtS has significant hydrogen evolution performance, while in the bilayer, the electron band distribution shows complete oxygen evolution ability, which indicates that the proposed monolayer and bilayer TlPtS are potential novel 2D materials suitable for photocatalytic water splitting driven by visible light.