Polyol Synthesized Y2Zr2O7:Bi3+, Tb3+ Phosphors with Tunable Blue–Green Emission for Display Applications

A low-cost polyol synthesis route was used to prepare Y₂Zr₂O₇ (YZO) phosphors doped with Bi³⁺ (1–2.5 at %) and co-doped with Tb³⁺ (1–3 at %). The structural, morphological, and optical properties were characterized using XRD, FESEM, UV-Vis, and PL spectroscopy. The Rietveld refinement of the XRD patterns confirmed that the undoped YZO host crystallizes in a cubic pyrochlore structure with the Fd\({{\bar {3}}}\)m space group. The FESEM images revealed agglomerated granule-like particles with an average size of ~105 nm. The UV-Vis absorption spectra showed characteristic peaks of Bi³⁺ and Tb³⁺ ions. The Photoluminescence studies demonstrated a blue emission at ~430 nm from the Bi³⁺ (³P₁ → ¹S₀ transition) under 305 nm excitation, with an optimal composition of YZO:1.5% Bi³⁺. Further, Co-doping with Tb³⁺ and exciting at 225 nm produced weak blue emissions and a dominant green emission at 545 nm from the ⁵D₄ → ⁷F₅ transition of Tb³⁺ ions. The optimal composition of the phosphor sample is identified to be Y_1.965Zr₂O₇:1.5% Bi³⁺, 2% Tb³⁺ which exhibits tunable blue–green emissions supported by lifetime decay analysis and energy transfer between Bi³⁺ and Tb³⁺ ions. The CIE chromaticity coordinates indicate its potential for display applications.