Synthesis and luminescence properties of Sm3+ doped CaTiO3 nanophosphor for application in white LED under NUV excitation

Abstract

CaTiO3:Sm3+ (1–11mol%) nanophosphors were successfully synthesized by a low temperature solution combustion method [LCS]. The structural and morphological properties of the phosphors were studied by using Powder X-ray diffractometer (PXRD), Fourier transform infrared (FTIR), X-ray photo electron spectroscopy (XPS), scanning electron microscope (SEM) and transmission electron microscopy (TEM). TEM studies indicate that the size of the phosphor is ∼20–35nm. Photoluminescence (PL) properties of Sm3+ (1–11mol%) doped CaTiO3 for NUV excitation (407nm) was studied in order to investigate the possibility of its use in White light emitting diode (WLED) applications. The emission spectra consists of intra 4f transitions of Sm3+, such as 4G5/2→6H5/2 (561nm), 4G5/2→6H7/2 (601–611nm), 4G5/2→6H9/2 (648nm) and 4G5/2→6H11/2 (703nm) respectively. Further, the emission at 601–611nm show strong orange–red emission and can be applied to the orange–red emission of phosphor for the application for near ultra violet (NUV) excitation. Thermoluminescence (TL) of the samples irradiated with gamma source in the dose range 100–500Gy was recorded at a heating rate of 5°Cs−1. Two well resolved glow peaks at 164°C and 214°C along with shouldered peak at 186°C were recorded. TL intensity increases up to 300Gy and thereafter, it decreases with further increase of dose. The kinetic parameters namely activation energy (E), frequency factor (s) and order of kinetics were estimated and results were discussed in detail.