Synthesis and Host-Sensitized Luminescence in Mg <sub>2</sub> YVO <sub>6</sub> :M <sup>3+</sup> (M = Eu, Er, Sm, Dy, Tm, Bi) Phosphor for Application in Human-Centric Lighting
Ashvini Pusdekar, Nilesh S. Ugemuge, Renuka Nafdey, S. V. Moharil
Abstract
Luminescence of lanthanides Eu 3+, Er 3+, Sm 3+, Dy 3+, Tm 3+, and the ns 2 activator Bi 3+ was explored in the Mg 2 YVO 6 host. An excitation band around 330 nm was a common feature for all of these phosphors; hence, this was attributed to the host, specifically to the 1 A 1 → 1 T 2 transition of the (VO 4 ) 3– group. Pure Mg 2 YVO 6 also exhibited blue emission when excited at 330 nm. The luminescence of the above-mentioned activators is thus host-sensitized. A variety of emission colors, which included primary colors red, green, and blue, as well as cyan and yellow, were observed in different activators. All these phosphors exhibited intense emission. Human-centric LED lamps were designed by blending these phosphors and coating them on a PCF-10-V1 315 nm LED chip. Different blends produced a range of LED parameters. The correlated color temperature could be adjusted in the range of 3100–5200 K, and the color rendition index in the range of 53–83. Most importantly, the circadian action factor of the prototype LED lamps was much lesser than that of the existing white LED lamps produced with blue chips and YAG:Ce phosphor. Low CAF is essential for avoiding the side effects of the existing white LED lamps arising from blue light. The results show that through doping rare-earth ions into Mg 2 YVO 6 host, the luminescent intensity was enhanced, the CIE coordinates were adjusted, and the correlated color temperature was reduced, demonstrating that Mg 2 YVO 6:M 3+ (M = Eu, Er, Sm, Dy, Tm) phosphors are promising single-phase converting phosphors for white LEDs with UV chips.