Eu3+-Activated Sr3ZnTa2O9 single-component white light phosphors: emission intensity enhancement and color rendering improvement

Abstract

Single-component white light phosphors with a broad and full color spectrum are urgently required to overcome residual problems with commercial phosphors. In this paper, we describe how Eu³⁺, as the dopant of Sr₃ZnTa₂O₉ (SZT), plays an important role in structural modulation (including structural order–disorder and intrinsic oxygen defects), as demonstrated by electronic structural calculations and systematic experiments. Furthermore, ⁵D₀ → ⁷F₂ emission of Eu³⁺ provides the red component of the emission spectrum and increases the color rendering index of SZT:Eu³⁺ phosphors. Consequently, the resulting phosphor SZT:10%Eu³⁺ shows significantly enhanced emission intensity, and its broadband emission covers the entire visible region from 400 nm to 720 nm. A fabricated LED device using a near-ultraviolet 370 nm chip coated with a single-component, the SZT:10%Eu³⁺ phosphor, shows warm white emission with a high color rendering index (R_a = 82).