Influence of TiO2 concentration on the characteristics of ZnO nanoparticles fabricated via sonication assisted with gelatin

Highlights: • The effect of ultrasonication and gelatin addition on TiO₂@ZnO nanocomposites was reconnoitered. • The analysis revealed titanium rutile phase formation and band gap widening were observed. • The electrical investigation exhibited conductivity drop and grain boundary resistance effects of TiO₂ doping. Herein, TiO₂@ZnO nanocomposites were prepared via ultra-sonication using gelatin as a stabilizing agent. The structural characterization revealed the development of a rutile TiO₂ phase that monotonically increased with TiO₂ loading as confirmed by the Raman active modes. The micrographs indicated reduced size spherical structures endorsing the XRD 43 – 37 nm crystallite sizes and the EDS data ascertained the inclusion of Zn, Ti, and O in the nanocomposites. A Burstein-Moss band gap widening effect from 3.196 eV for pure ZnO to 3.237 eV was exhibited by the highest TiO₂ content. A decrease in dielectric constant and ac conductivity (from 4.12 × 10⁻⁴ Ω⁻¹.cm⁻¹ for bare ZnO to 1.41 × 10⁻⁴ Ω⁻¹.cm⁻¹ for highest doped sample) as a function of frequency and TiO₂ loading. The Nyquist plot exhibited single semicircle arcs and increased bulk resistance from 0.025 to 3.00 × 10⁷ Ω due to doping connoting the prevalence of grain boundary resistance.