Tunable optoelectronic, thermoelectric, and photocatalytic properties of β-SiTe and SiH monolayers as a photocatalytic water-splitting

One of the most interesting study areas in the renewable energy production is highly efficient water splitting that relies on the solar energy. More promising photocatalysts which can operate under irradiation from visible light are vitally required. Herein, based on the density functional theory, we demonstrated that two-dimensional SiH and β-SiTe monolayers exhibit indirect bandgap and suitable band edge locations for photocatalytic splitting of water. Using the PBE approach, we found that the bandgap values for the SiH and β-SiTe monolayer are 2.19 eV and 1.86 eV, respectively. The rectified bandgaps using the HSE06 function for SiH and β-SiTe were 2.93 eV and 2.43 eV, respectively. Surprisingly, photocatalytic property studies demonstrated that SiH and β-SiTe monolayers act as efficient photocatalysts for the production of hydrogen. Our outcomes emphasized that the highest peak of the absorption coefficient of SiH monolayer is 17.1 × 10⁴ cm⁻¹ in the UV region specifically at energy 7.90 eV. While β-SiTe monolayer has two peaks absorption of (13.5 × 10⁴ and 8.1 × 10⁴) cm⁻¹ in the UV region at energies (7.18 and 9.22) eV. The results presented here imply that the SiH and β-SiTe could be useful in thermoelectric applications and the construction of photovoltaic cells and catalysts.