Photoluminescence and photocatalytic activity of rare earth ions doped anatase TiO2 thin films

TiO2 thin films doped with 1% rare earth (RE) ions (Sm3+, Eu3+, and Dy3+) have been deposited by the sol-gel spin coating technique. The X-ray diffraction, confocal Raman, optical transmittance, and photoluminescence spectra of resultant films were recorded at room temperature (RT). As revealed by X-ray diffraction, RE ions doped TiO2 films were found to have a tetragonal crystal structure with anatase phase TiO2. The crystallite size gets declined with RE (III) ions doping. TEM analysis of 1% Sm3+ ions doped TiO2 and 1% Dy3+ ions doped TiO2 films endorsed the particles have spherical shape structure with an average size of about 10.9 nm and 10.5 nm, respectively. The characteristic vibrational Raman modes also revealed that the RE ions doped TiO2 films founded to anatase phase. The RE ions doped TiO2 nanostructures have high refractive indices and narrow band gaps. Under UV (375 nm, 388 nm, and 393 nm) excitations, the RE ions doped TiO2 nanophosphor thin films show characteristic photoluminescence in the visible spectral range. The PL decay spectra were recorded by time correlated single photon counting (TCSPC) and the decay times of phosphors were obtained by bi-exponential curve fitting. The RE ions doped Titania films possessing significant color coordinate (x, y) values might have potential uses in solid-state display devices. The photocatalytic ability of RE ions doped TiO2 showed that the excellent photocatalytic activity (PCA) response for the degradation of methyl orange (MO) under visible light irradiation.

Automated summary

TiO2 thin films doped with 1% rare earth ions using the sol-gel spin coating technique exhibit tetragonal crystal structure with anatase phase and reduced crystallite size. The films show high refractive indices and narrow band gaps, with characteristic photoluminescence under UV excitations. The doped TiO2 films also demonstrate excellent photocatalytic activity for the degradation of methyl orange under visible light irradiation.