White‐light emission and red scintillation from Mn2+ ions single‐doped aluminum‐silicate glasses

Abstract

AbstractA series of Mn2+ single‐doped 0.2Gd2O3‐0.2Al2O3‐0.6SiO2 (GAS: xMn2+) glasses with Si3N4 as reducing agent were prepared. The presence of [SiO4‐x] defects and Mn2+ ions was determined from the absorption and excitation spectra of the glasses. With the increase of Mn2+ concentration, the intensity of blue emission decreases, while the intensity of red emission increases. The color coordinate of GAS: 6Mn2+ glass is (0.264, 0.226). The lifetime of the glasses was tested. Under the monitoring of 440 nm, the fast components (τf) are between 17 and 85 μs, and the slow components (τs) are between 200–650 μs. The former belongs to [SiO4‐x] defects, and the latter is [4E(G), 4A1(G)]→6A1(S) transition of Mn2+ ions. Under the monitoring at 630 nm, the τf are between 110 and 300 μs, and the τs are between 680 and 1220 μs, which are due to 4T1(G)→6A1(S) transition of Mn2+ ions and Mn2+ pairs, respectively. The energy transfer mechanism of [SiO4‐x] defect→Mn2+ ions are explained. The efficient [SiO4‐x] defect →Mn2+ ions energy transfer process was demonstrated by time‐resolved photoluminescence, and the energy transfer efficiency is over 85%. The maximum photoluminescence quantum yield (PL QY) of the glasses can reach 15.87%. The thermal activation energy of the glasses was calculated. In addition, X‐ray excited red luminescence spectra and the mechanism of the glasses were investigated.