Abstract
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 Y1.965Zr2O7:1.5% 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.
