Bright White‐Emitting Phosphors Ba2Gd(BO3)2Cl: Dy3+/Dy3+‐Tm3+ for Hg‐Free Lamps and White LEDs Applications

Abstract

Spectroscopic properties of Ba2Gd(BO3)2Cl: Dy3+ and Ba2Gd(BO3)2Cl: Dy3+, Tm3+ under vacuum ultraviolet (VUV) and ultraviolet (UV) light excitations were investigated. Dy3+ single‐doped Ba2Gd(BO3)2Cl showed broad absorption band in the VUV region, and bright warm white light with chromaticity coordinates (CIE) of (0.340, 0.381) upon VUV excitation at 172 nm, demonstrating this phosphor's applicability in mercury free lamps. Upon direct excitation Tm3+ from its 6F6 level to 1D2 level, the decrease of emission intensity and lifetime of Tm3+ 1D2–3F4 emission with increasing concentration of Dy3+ in Ba2Gd(BO3)2Cl: Dy3+, Tm3+ confirmed the occurrence of energy transfer from Tm3+ to Dy3+. In addition, Ba2Gd(BO3)2Cl: Dy3+, Tm3+ could be efficiently excited by 358 nm UV light and its emission color could be tuned from blue to yellow by codoping Tm3+. When 1% Tm3+ and 5% Dy3+ were codoped in the Ba2Gd(BO3)2Cl, intensive white‐emitting light with CIE of (0.352, 0.328) and correlated color temperature of 4589 K was achieved upon 358 nm excitation, revealing the potential application of Ba2Gd(BO3)2Cl: Dy3+, Tm3+ for white light‐emitting diodes (LEDs).