Elemental composition, spectral characteristics, and quantum chemical insights into SRTIO3 perovoskite
Abstract
The sol-gel synthesized SrTiO<sub>3</sub> perovskite was investigated by EDS analysis, which confirmed that its chemical composition was in good agreement with the initial precursors, both qualitatively and quantitatively. UV-Vis absorption spectra revealed a sharp decrease in light intensity in the 250÷300 nm region, while the absorption in the visible range remained relatively weak. This optical behavior suggests that the material is well suited for photocatalytic applications and optoelectronic devices operating in the ultraviolet region. Furthermore, the structural and electronic properties studied by DFT calculations at the B3LYP/6-31G** (d, p) level showed a band gap energy of approximately 3.2 eV corresponding to a wavelength of 387 nm, confirming its semiconducting nature. Thermodynamic analysis by DFT showed that the Gibbs free energy of formation (-379.6 kcal mol<sup>-1</sup>) reflects the high stability of SrTiO<sub>3</sub> and its spontaneous formation from elemental components under ambient conditions. The relatively low standard molar entropy indicates limited configurational freedom, consistent with the ordered crystalline nature of this perovskite oxide.