Enhanced Broad-Spectrum Protection Against High-Energy Visible Light Using Co-Doped Ag2O and ZnO–TiO2 Nanocomposites

An Ag₂O-Zn/TiO₂ (AZT) nanocomposite was developed to overcome the limitations of conventional ZnO- and TiO₂-based sunscreens, which offer UV protection but lack efficacy against high-energy visible (HEV) light. The nanocomposite was synthesized using a sol–gel co–doping method, incorporating Ag₂O to enhance photocatalytic activity and enable plasmonic absorption in the HEV range. Its morphological structure and elemental composition were analyzed using field emission scanning electron microscopy (FE-SEM) with energy-dispersive X-ray spectroscopy (EDX). X-ray diffraction (XRD) was used to assess the crystalline structure, and optical properties were evaluated using a UV–visible spectrophotometer. The nanocomposite exhibited crystallite sizes ranging from 28.6 to 33.2 nm, with a predominant rutile phase. Optical properties revealed an energy bandgap ranging from 2.16 to 3.02 eV and broad-spectrum absorption extending into the HEV region (417–574 nm). The incorporation of Ag₂O improved HEV attenuation compared to conventional ZnO and TiO₂. In vitro SPF testing showed that Ag₂O-Zn/TiO₂ provided moderate UV protection, with values comparable to conventional TiO₂. Notably, it offered a more balanced UVA/UVB protection profile, highlighting its potential as an effective broad-spectrum UV filter.