Optimizing ATO nanoparticles: synthesis and electrical properties for future electronic device applications

Tin dioxide plays a crucial role in gas detection, solar cells, and photocatalysis. This study focuses on nanostructured antimony-doped tin dioxide (ATO) synthesized via a modified sol–gel technique under supercritical co-solvent conditions. The crystalline structure and electrical properties were investigated with varying levels of antimony doping (1, 2, and 3 at.%). X-ray diffraction analysis revealed tetragonal rutile structure nanoparticles with sizes ranging from 13 to 22 nm, depending on the doping content. Impedance spectroscopy confirmed its semiconductor behavior, and dc conductivity exhibited a thermal activation, wherein the energy required for conduction progressively increased alongside Sb content. The ac conductivity followed the Jonscher law, dominated by the tunneling hopping mechanism. Nyquist diagrams assessed grain and grain boundary contributions, modeling samples through an equivalent circuit. The dielectric study identified interfacial polarization as the source of dielectric permittivity. The observed behavior of the imaginary component of impedance (Z′′) indicates a dielectric relaxation phenomenon within the sample, with activation energies closely matching those derived from the conductivity study. These findings elucidate the origins of conductivity and active sites in ATO nanoparticles, with deep implications for optoelectronic applications.