Achieving zero-thermal quenching luminescence in ZnGa2O4: 0.02Eu3+ red phosphor

Abstract The struggle with "thermal load" is always an unavoidable challenge for photo-luminescent material. In this work, a novel red phosphor of ZnGa2O4: Eu3+ with spinel-type structure is prepared by high-temperature solid-phase method. Due to the charge imbalance during the replacement processes of Ga3+→Zn2+ and Eu3+→Zn2+ in mixed spinel structure, vacancy defects can be introduced into the lattice structure of ZnGa2O4: 0.02Eu3+. The results of Density Function Theory (DFT) calculation demonstrate that the existence of vacancy defects can construct defect energy levels in the energy band structure of the host crystal, which can assist enhancing the fluorescence emission intensity of the phosphor at high temperature. The strong thermal stability of its own structure combined with the assistance of defect energy levels enables the achievement of zero-thermal quenching in ZnGa2O4: 0.02Eu3+ under multi-wavelength excitation. Our results open up a new way for the exploration and utilization of zero-thermal quenching phosphors.