Effect of gadolinium inclusion on the raman spectra and photoluminescence of TiO2 nanoparticles

GdxTi1-xO2 nanocomposites with x=0.00, 0.02, 0.04, 0.06, 0.08 & 0.10 were prepared through sol-gel method.  The samples were characterized using X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), High resolution scanning electron microscope (HR-SEM), Raman spectroscopy and photoluminescence spectroscopy (PL).  The XRD pattern and Raman spectra confirmed the presence of crystalline nature and phase pure anatase tetragonal system.  The average crystallite size of the samples was between 10 to 18 nm.  HR-SEM images indicated the formation of spherical like particles of GdxTi1-xO2 nanocomposites.  An obvious reduction in particle size of   GdxTi1-xO2 nanocomposites were noticed while comparing the SEM images of bare TiO2 and composite samples.  Coupling of Gd is responsible for slight blue shift in absorption edge.  The presence of oxygen vacancies is confirmed in Raman and PL spectra.  These oxygen vacancies potentially trap electrons and restrict the electron-hole recombination and thus improve the photocatalytic reactions.