Fluorescence improvement of Ba1.3Ca0.7SiO4:EU2+,Mn2+ phosphors via Dy3+ addition and their color-tunable properties

A series of novel single-phase white phosphors Ba1.3Ca0.69-x-ySiO4:0.01Eu(2+),xMn(2+), yDy(3+) were synthesized by the solid-state method. The excitation spectra of these phosphors exhibit a broad band in the range of 260-410 nm, which can meet the application requirements for near-UV LED chips (excited at 350-410 nm). The emission spectra consist of two broad bands positioned around 455 nm and 596 nm, which are assigned to 5d -> 4f transition of Eu2+, and T-4(1)->(6)A(1) transition of Mn2+, respectively. The luminescence intensity of phosphors enhances obviously by doping Dy3+ ions, and the intensity of two bands reaches an optimum when Dy3+ amounts to 2 mol%. In addition, thermoluminescence investigation of phosphor was conducted, getting two shallow trap defects with activation energy of 0.43 eV and 0.45 eV, which demonstrates the energy transfer mechanism of Dy-Eu through the process of hole and electron traps. By precisely tuning the Mn2+ content, an optimized white light with color rendering index (CRI) of R-a=84.3%, correlated color temperature (CCT) of T-c=8416 K and CIE chromaticity coordinates of (0.2941, 0.2937) is generated. The phosphor could be a potential white phosphors for near-UV light emitting diodes. (C) 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.