Fluorescence regulation derived from Eu³⁺ in miscible-order fluoride-phosphate blocky phosphor

Miscible-order fluoride-phosphate blocky phosphor (FBP), composed with ordered-phase of NaYF₄ crystals and unordered phase of tin-fluorophosphate glass, is prepared by a two-step process and luminescent properties of FBPs embedded with different particle sizes of NaYF₄ crystals are presented. High-frequency fluorescence from higher metastable ⁵D_J (J = 1, 2 and 3) energy levels are effectively released in Eu³⁺ doped fluoride crystals. Taking the blue emission of Sn²⁺ as the framework, multi-peak emissions from metastable energy levels are controlled to adjust the color coordinates of the FBP to the white-light region, which the color rendering index (CRI) reaches 89. Tunable color FBP with high CRI retains splendid luminescence property of fluoride, providing a potential candidate for the development of white LED.