Fabrication and characterization of rare earth-free nanophosphor based devices for solid-state lighting applications

Abstract

This study presents a novel, rare-earth-free Zn₃V₂O₈ nanophosphor (ZnVO NP) with exceptional luminescent properties, making it ideal for phosphor-converted white light-emitting diodes (pc-WLEDs). When coupled with a 385 nm LED chip, ZnVO NP delivers white light with a correlated color temperature of approximately 4920 K, a high quantum yield of 74%, and an excellent color rendering index (CRI) of R_a = 91. Notably, the R₉ value of 90.5 surpasses that of commercially available Y₃Al₅O₁₂:Ce³⁺ (R₉ = 14.3), highlighting superior red color rendering. The white light, excited at 385 nm, has CIE coordinates of (0.330, 0.301). Temperature-dependent photoluminescence spectra indicate high thermal stability, with emission peaking in the yellow region at CIE coordinates (0.43, 0.52) under 290 nm, 361 nm, and 385 nm excitation. This broadband yellow-emitting ZnVO NP offers a promising rare-earth-free alternative for pc-WLEDs, providing excellent color quality and stability under diverse operating conditions, demonstrating its practical potential in advanced lighting applications.