Multichannel emissions from ⁵D_J metastable levels of Eu³⁺ in miscible-phase phosphors

BaYF₅: Eu³⁺-fluorophosphate (BYF: E-FP) miscible-phase phosphors with tunable white fluorescence and high color-rendering index (CRI) are synthesized by blending Ba(Y_1−xEu_x)F₅ (BYF: E) submicron crystals (SCs) into fluorophosphate glass. Adjusting the concentration of Eu³⁺ purposefully, the comparable intensity of blue, green and red components by multichannel emissions can be regulated to achieve the adjustable white light. The quantum efficiency of ⁵D₀ level in Eu³⁺ reaches up to 90.8%, and the millisecond fluorescence lifetime of blue and green emissions from ⁵D₁, ⁵D₂ and ⁵D₃ levels exhibit the effectiveness of metastable levels. In coordination with blue emission from Sn²⁺, the color coordinates of BYF: E-FP are concentrated in white region of chromaticity diagram and its CRI is able to reach as high as 86. Tunable white fluorescence and high CRI indicate that miscible-phase phosphors possess promising applications in optoelectronic lighting.