Cr 3+ Doping Effects on Structural, Optical, and Morphological Characteristics of BaTiO 3 Nanoparticles and Their Bioactive Behavior.

This study investigates the effects of chromium (Cr³⁺) doping on BaTiO₃ nanoparticles synthesized via the sol–gel route. X-ray diffraction confirms a Cr-induced cubic-to-tetragonal phase transition, with lattice parameters and crystallite size varying systematically with Cr³⁺ content. UV–visible spectroscopy reveals a monotonic decrease in bandgap energy from 3.168 eV (pure BaTiO₃) to 2.604 eV (5% Cr³⁺-doped BaTiO₃). Raman and FTIR spectroscopy elucidate structural distortions and vibrational mode alterations caused by Cr³⁺ incorporation. Transmission electron microscopy and energy-dispersive X-ray spectroscopy verify nanoscale morphology and successful Cr³⁺ doping (up to 1.64 atom%). Antioxidant activity, evaluated using the DPPH assay, shows stable radical scavenging for pure BaTiO₃ (40.70–43.33%), with decreased activity at higher Cr³⁺ doping levels. Antibacterial efficacy against Escherichia coli peaks at 0.5% Cr³⁺ doping (10.569 mm inhibition zone at 1.5 mg/mL), decreasing at higher concentrations. This study demonstrates the tunability of structural, optical, and bioactive properties in Cr³⁺-doped BaTiO₃ nanoparticles, highlighting their potential as multifunctional materials for electronics, photocatalysis, and biomedical applications. [ABSTRACT FROM AUTHOR]