Authors : D.N. Game, C. B. Palan, N.B. Ingale, S.K. Omanwar
Page Nos : 198-203
Description :
We have synthesized NaCaPO4 white emitting phosphors by modified solid state diffusion method doped with different concentration of Dy3+. Crystal structure, surface morphology, photoluminescence properties, concentration quenching, color co-ordinates and other characteristics of these phosphors with reference to SSL are studied. These phosphors exhibit number of excitation peaks in nUV region. Emission spectra have two characteristic narrow bands of Dy3+ at 481 nm (blue) and 575 nm (yellow) in visible spectrum resulting into white light emission with FWHM of these bands is around 20 nm. The XRD pattern of prepared phosphor well matches with JCPDS Card No.76-1456. Synthesized phosphor particles are of different sizes, with smooth surfaces, from less than 1 micron to few microns. CIE coordinates are (0.278, 0.298) at 351 nm (λex) falls in white region of CIE diagram in the close vicinity of standard white point C. These results indicates that the synthesized phosphors are promising material for a color converter using nUV LED as the primary light (pumping) source in phosphor converted white LED for solid state lighting.
