A thermally stable lithium yttrium phosphate phosphor for solid-state lighting

Abstract

In this work, trivalent dysprosium was incorporated with lithium yttrium phosphate LiY₅P₂O₁₃ (LYP), obtaining a yellow-emitting material. The crystallographic sites of introduced Dy³⁺ activators are determined through the comprehensive analysis of the XRD investigation, DFT computation, and experimental luminescence spectra. Under 353 nm excitation, the LYP:Dy³⁺ phosphor shows bright yellow emission owing to dominant ⁴F_9/2 → ⁶H_13/2 transition (577 nm) of Dy³⁺. The luminescence quenching occurs when the Dy³⁺ content exceeds 0.07 mol, originating from the dipole–dipole interaction. Furthermore, the excellent thermal stability behavior (84 % at 423 K) and good resistance to color shifting (0.00634 at 473 K) for title phosphor are manifested by temperature-dependent investigation. Eventually, the w-LED fabricated with LYP:0.07Dy³⁺ and commercial materials exhibits stable white-emitting output (0.3595, 0.3179) with high R_a (85) and low CCT (4203 K). All the study demonstrates that the LYP:Dy³⁺ material is a perspective candidate in solid-state illustration field.