UV-inspired three rare-earth-doped molybdate glass and NaGd(MoO4)2 glass-ceramic phosphors for white LEDs

To seek novel fluorescent materials, a series of three rare-earth-doped molybdate precursor glass (PG) and glass-ceramics (GCs) containing NaGd(MoO 4 ) 2 nanocrystals were achieved by high-temperature melting and subsequent controlled crystallization technique. The results reveal that adjustable color emission from blue to white region can be achieved in PG specimen with increasing contents of Eu 3+ ions. At the optimal concentration of 1.4Tm 3+ /2.8Tb 3+ /0.8Eu 3+ , the PG exhibits the color coordinates of (0.3279, 0.3142) and correlated color temperature of 5737 K, and the obtained GC sample (GC720) after heat treatment at 720 °C shows the correlated color temperature of 6106 K and the color coordinates of (0.3138, 0.3173), which are closest to the standard white light. The fluorescence luminescence intensity of GC720 is significantly higher than that of PG. Decay curves and photoluminescence spectra verify the existence of energy conversion from Tb 3+ and Tm 3+ to Eu 3+ . Furthermore, the LED lamps encapsulated with GC720 and PG emit a bright white light and have a high color-rendering index of more than 86. These findings demonstrate that the developed 1.4Tm 3+ /2.8Tb 3+ /0.8Eu 3+ doped PG and GC720 have tremendous potential in white LEDs.