Photoluminescence Mechanism and Thermal Stability of Tb ³⁺ ‐Doped Y ₄ Si ₂ O ₇ N ₂ Green‐Emitting Phosphors

Abstract

With solid‐state reaction method, series of Y 4 Si 2 O 7 N 2 :Tb 3+ phosphors were prepared under the high‐temperature and high‐pressure conditions. The photoluminescence properties at room and high temperature were investigated. Two groups of emission lines have been observed, which are corresponding to Tb 3+ 5 D 3 → 7 F J ( J = 6, 5, 4, 3, 2) and 5 D 4 → 7 F J ( J = 6, 5, 4, 3) transitions. The physical mechanisms for excitation, emission, concentration quenching, and thermal quenching were investigated. The cross‐relaxation mechanism between the 5 D 3 and 5 D 4 emission was investigated and discussed. The Tb–Tb critical distance for cross‐relaxation was calculated to be ~13 Å. The optimum Tb 3+ concentration in this phosphor is 15 mol%. The quadrupole–quadrupole interaction dominates the non‐radiative energy transfer between the Tb 3+ luminescence centers and causes the concentration quenching. This phosphor shows high thermal stabilities that at 150°C the intensity remains 92% compared with that measured at room temperature. The present work suggests that this Tb 3+ ‐doped Y 4 Si 2 O 7 N 2 material is a kind of potential green‐emitting phosphor.