Fine Band Gap Tuning Via Sr Incorporated PbTiO3 for Optoelectronic Application: a DFT Study

To examine the impacts while taking cubic PbTiO 3 with various Sr concentrations, a thorough theoretical analysis is conducted. This study evaluates the effects of adding Sr to the ab-initio method using the generalized gradient approximation (GGA), which is used in the Cambridge serial total energy package (CASTEP), on the structural, total, and partial density of states (TDOS/PDOS), modification in the electronic bandgap, and optical properties. All of the PbTiO 3 structural properties are in good agreement with previously published values. For 100% Sr substitution, a change in the perfect cubic structure of SrTiO 3 is seen. The indirect bandgap of pure PbTiO 3 is found to be 1.655 eV. Due to the non-linear band gap dependency on the composition of the material, a reduction in bandgap is recorded by increasing the Sr percentage. As the Sr atoms in PbTiO 3 are repeatedly added, the contribution of these orbitals in creating energy states increases. Numerous optical properties have been compared throughout a range of Sr concentrations, and the results show that SrTiO 3 exhibits modified optical behaviour and a lower refractive index than PbTiO 3 . It is also shown how these optical characteristics change with Sr content. We suggest using this SrTiO 3 cubic phase as a possible material for optoelectronic applications.