Calcium Aluminate Phosphor Supported TiO2 Nanoparticles
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초록
Rare earth based calcium aluminate phosphor (CaAl2O4:Eu2+, Nd3+) supported TiO2 nanoparticles are synthesized by using sol-gel method, which are further characterized using powder X-ray diffraction (XRD), fourier transform infrared (FT-IR), diffuse reflectance UV-Visible spectroscopy (DRS UV-Vis) and transmission electron microscopy (TEM). The XRD pattern of as-prepared and sintered phosphor supported TiO2 does not show the tendency to change the crystal structure from anatase to rutile phase up to 600oC. This indicates that the phosphor support might inhibit the densification and crystallite growth by providing dissimilar boundaries. The diffuse reflectance spectral (DRS) measurements showed shift towards longer wavelength indicating reduction in the band-gap energy as compared to free TiO2. The FT-IR spectra of phosphor supported TiO2 nanoparticles show shift in the peak positions to lower wavelengths. This indicates that the TiO2 nanoparticles are not free, but covalently bonded to the phosphor support. TEM micrographs show presence of crystalline and spherical TiO2 nanoparticles (8 - 15 nm diameter) dispersed uniformly on the surface of phosphor.
Abstract
Rare earth based calcium aluminate phosphor (CaAl2O4:Eu2+, Nd3+) supported TiO2 nanoparticles are synthesized by using sol-gel method, which are further characterized using powder X-ray diffraction (XRD), fourier transform infrared (FT-IR), diffuse reflectance UV-Visible spectroscopy (DRS UV-Vis) and transmission electron microscopy (TEM). The XRD pattern of as-prepared and sintered phosphor supported TiO2 does not show the tendency to change the crystal structure from anatase to rutile phase up to 600oC. This indicates that the phosphor support might inhibit the densification and crystallite growth by providing dissimilar boundaries. The diffuse reflectance spectral (DRS) measurements showed shift towards longer wavelength indicating reduction in the band-gap energy as compared to free TiO2. The FT-IR spectra of phosphor supported TiO2 nanoparticles show shift in the peak positions to lower wavelengths. This indicates that the TiO2 nanoparticles are not free, but covalently bonded to the phosphor support. TEM micrographs show presence of crystalline and spherical TiO2 nanoparticles (8 - 15 nm diameter) dispersed uniformly on the surface of phosphor.
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