Influence of aluminium doping on structural and optical properties of tin oxide nanoparticles

The major mechanism for activating and regulating optical characteristics, particularly band gap, in semi-conducting oxides has been theorised to be variations in dopant concentration. Nanoparticles of Sn1-xAlxO2 (x = 0.0, 0.01, 0.02, 0.03, 0.04) have been synthesized by the sol-gel method and characterized by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), FESEM, DRS, photoluminescence (PL), Raman spectroscopy. XRD measurements revealed that all the samples crystalize in tetragonal structure which was further supported by Raman spectroscopy. As the Al content grew from 0% to 4%, it was seen that the size of the crystallites varied from 8.89 nm to 4.01 nm. Using the Tauc relation, the optical band gap was computed, and it was discovered that it decreases from 3.44 eV to 3.05 eV as the Al concentration rose. Photoluminance measurements (PL) revealed that all the samples show violet emissions. Also, it was found that 3% doped sample shows lowest PL intensity which implies that the material has profound applications in photocatalysis, lithium-ion batteries and so on. Further, it was also observed that 3% aluminium doping is the optimum concentration for tin oxide sample to be used in photocatalytic applications.