Role of flux on morphology and luminescence properties of Sm3+ doped Y2SiO5 nanopowders for WLEDs

Abstract

The study involves preparation of samarium doped Y2SiO5 (YSO) nano powders by solution combustion method using urea as a fuel for the first time. Effect of different fluxes on the crystallization behavior, morphology and photoluminescence (PL) properties of YSO:Sm3+ (1–9mol%) were investigated. The final product was characterized by Powder X-ray diffraction (PXRD), Scanning Electron Microscopy (SEM) and UV–Vis spectroscopy. The average crystallite size estimated by Debye–Scherer’s and Williamson–Hall plots were found to be in the range of 10–50nm. Samples calcined at 1100°C show pure monoclinic X1 phase; whereas, samples calcined at 1200 and 1300°C show pure X2 phase of YSO. Photoluminescence (PL) studies of Sm3+ (1–9mol%) doped YSO for near ultra violet (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 (∼560nm), 4G5/2→6H7/2 (600–613nm), 4G5/2→6H9/2 (∼650nm), 4G5/2→6H11/2 (715nm) and 4G5/2→6H13/2 (763nm) respectively. The emission intensity of the phosphor was found to be enhancing after addition of fluxes. Further, the emission at 600–613nm show strong orange–red emission and can be applied to the orange–red emission of phosphor for near ultra violet excitation.