Investigation of thermal quenching and abnormal thermal quenching in mixed valence Eu co-doped LaAlO3 phosphor

Temperature dependent luminescence of mixed valence Eu co-doped LaAlO3 phosphors are deeply investigated in this work. Different temperature properties of Eu2+ and Eu3+ luminescence are observed as the phosphor excited by different incident light. Eu3+ luminescence shows normal thermal quenching when excited at 320 nm and abnormal thermal quenching as the excitation light changed into 365 nm, while Eu2+ luminescence exhibits a normal thermal quenching independent on the incident excitation lights. The origin of these novel normal/abnormal thermal quenching phenomena are analyzed and discussed by the excitation-emission processes in terms of the configuration coordinate model. The presented important experimental and analysis results give insights into the temperature properties of phosphors.