Ruddlesden-Popper compound Sr2TiO4 doped with chalcogens for optoelectronic applications: Insights from first-principle calculations

Doping techniques are generally used as an effective means for tailoring the physical features of a target compound. In this research paper, we investigated the effect of different concentrations of oxygen group elements on the structural, electronic, and optical properties of Ruddlesden-Popper compound Sr₂TiO₄ by using first-principles density functional theory calculations with LSDA + TB-mBJ approach. Formation energies of each doped structure are computed to examine the feasibility of the synthesis. The findings suggest that the band gaps are significantly reduced by increasing chalcogens concentration, and the absorption ability is improved in the visible light (380~790 nm). Therefore, Sr₂TiO_4-xY_x (Y = S, Se, Te) quaternary alloys may be promising materials in advanced optoelectronic and solar cell applications. Other optical properties, such as optical band gap, Urbach energy, and optical conductivity, are also studied and the results indicate that the doped compounds are significantly absorbent and productive.