Photoluminescence Mechanism and Thermal Stability of Tb3+‐Doped Y4Si2O7N2 Green‐Emitting Phosphors

With solid-state reaction method, series of Y4Si2O7N2:Tb3+ 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 Tb3+ 5D3 → 7FJ (J = 6, 5, 4, 3, 2) and 5D4 → 7FJ (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 5D3 and 5D4 emission was investigated and discussed. The Tb–Tb critical distance for cross-relaxation was calculated to be ~13 A. The optimum Tb3+ concentration in this phosphor is 15 mol%. The quadrupole–quadrupole interaction dominates the non-radiative energy transfer between the Tb3+ 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 Tb3+-doped Y4Si2O7N2 material is a kind of potential green-emitting phosphor.