Aluminum-doped SnO2 nanoparticles: Synthesis, structural, and optical modifications for enhanced photocatalytic environmental applications

Aluminum-doped tin oxide (ATO) nanoparticles were synthesized using the sol-gel method and analyzed for structural, morphological, and optical properties. X-ray diffraction confirmed the successful incorporation of Al3+ ions into the SnO2 lattice, retaining its tetragonal rutile structure. The shifts in diffraction peaks to higher 2θ values indicated lattice contraction due to the smaller ionic radius of Al3+ compared to Sn4+. Scanning electron microscopy revealed a uniform particle distribution with reduced agglomeration. UV–visible spectroscopy exhibited a hypsochromic shift in the absorption edge, attributed to bandgap widening caused by aluminum doping. Fourier transform infrared spectroscopy identified characteristic vibrational modes of functional groups, confirming chemical bonding. Photoluminescence studies showed enhanced emission intensities due to oxygen vacancies and electronic interactions between Al dopants and the SnO2 lattice, suggesting defect state creation. The proposed structural and optical characteristics suggest improved charge separation and light absorption, highlighting the potential of ATO nanoparticles for photocatalytic pollutant degradation, environmental remediation, gas sensing, and optoelectronic applications.