Luminescence investigation of red phosphors Ca0.54Sr0.34-1.5xEu0.08Smx(MoO4)y (WO4)1-y for UV-white LED device

Ca0.54Sr0.34-1.5xEu0.08Smx(MoO4)y (WO4)1-y red phosphors were prepared by solid-state reaction using Na+ as a charge compensator for light-emitting diodes (LED). The effects of Na+ concentration, synthesis temperature, reaction time and Eu3+ concentration were studied for the properties of luminescence and crystal structure of red phosphors. The results show that the optimum reaction condition is 6%, 900 deg. C, 2 h and 8%. The photoluminescence spectra show that red phosphors are effectively excited at 616 nm by 292, 395 and 465 nm. The wavelengths of 465 nm nicely match the widely applied emission wavelengths of blue LED chips.