Predominant green emission of Ce3+–Tb3+ activated Y7O6F9 phosphors

Abstract

Ce³⁺–Tb³⁺-doped Y₇O₆F₉ vernier phosphors composed of Y_7(1−m−n)Ce_7mTb_7nO₆F₉ (m = 0.01–0.1, n = 0–0.15) were prepared using a flux-assisted solid-state reaction. The X-ray diffraction patterns of the resultant phosphors were examined to index the peak positions. The photoluminescence (PL) excitation and emission spectra of the Tb³⁺-activated yttrium-oxyfluoride phosphors were clearly monitored with critical emission quenching as a function of Tb³⁺ content in Y_7(1−n)Tb_7nO₆F₉. After doping the Y₇O₆F₉ structure with Ce³⁺ and Tb³⁺ activators, significantly enhanced green emission were observed in the PL spectra under near-ultraviolet (NUV) excitation. The dependence of the luminescent intensity of the Tb³⁺ co-doped (n = 0, 0.01, 0.05, 0.1, 0.15) host lattices on Ce³⁺ content (m = 0.01, 0.05) was also investigated. Co-doping Tb³⁺ into the Ce³⁺-doped host structure enabled strong energy transfer from Ce³⁺ to Tb³⁺; this energy transfer mechanism is discussed. The intense green emission light was compared with that from a commercial green phosphor at room temperature.