Long-lasting phosphor Y2O2S : Eu^3+ , Mg^2+ , Ti^4+ was synthesized by a flux method and their luminescence properties were investigated. The result indicates that the unit cell parameter c is linearly increased w...Long-lasting phosphor Y2O2S : Eu^3+ , Mg^2+ , Ti^4+ was synthesized by a flux method and their luminescence properties were investigated. The result indicates that the unit cell parameter c is linearly increased with the increase of Eu2O3 content in Y2O2S: Eu^3+ (0.01 ≤ x ≤0.10). On the other hand, the change of unit cell parameter a is not linear dependence. In the Y2O2S: Eu^3 + crystal structure, Eu^3+ ions only replaced Y^3 + ions' places in which it posited center position of c axis. With the increase of Eu2O3 content, the position of the strongest emission peak changed from 540 nm (5D1→^ 7F2 transition) to 626 nm (^5Do→^7TF2 transition), and the maximum intensity was obtained when x = 0.09 in Y2O2S: Eu^3+ (0.01 ≤x ≤0.10). This is due to the environment of trivalent europium in the crystal structure of Y2O2S. Doping with Mg^2+ or Ti^4+. ions alone cannot get the good long-lasting afterglow effect, whereas co-doping with Mg^2 + and Ti^4 + ions and excited with 365 nm ultraviolet light, a strong thermoluminesence peak appeared, red and orange long-lasting phosphorescence (LLP) was also observed and the phosphorescence lasted nearly 3 h in the light perception of the dark-adapted human eye (0.32 mcd·m^-2). Thus the LLP mechanism was analyzed.展开更多
文摘Long-lasting phosphor Y2O2S : Eu^3+ , Mg^2+ , Ti^4+ was synthesized by a flux method and their luminescence properties were investigated. The result indicates that the unit cell parameter c is linearly increased with the increase of Eu2O3 content in Y2O2S: Eu^3+ (0.01 ≤ x ≤0.10). On the other hand, the change of unit cell parameter a is not linear dependence. In the Y2O2S: Eu^3 + crystal structure, Eu^3+ ions only replaced Y^3 + ions' places in which it posited center position of c axis. With the increase of Eu2O3 content, the position of the strongest emission peak changed from 540 nm (5D1→^ 7F2 transition) to 626 nm (^5Do→^7TF2 transition), and the maximum intensity was obtained when x = 0.09 in Y2O2S: Eu^3+ (0.01 ≤x ≤0.10). This is due to the environment of trivalent europium in the crystal structure of Y2O2S. Doping with Mg^2+ or Ti^4+. ions alone cannot get the good long-lasting afterglow effect, whereas co-doping with Mg^2 + and Ti^4 + ions and excited with 365 nm ultraviolet light, a strong thermoluminesence peak appeared, red and orange long-lasting phosphorescence (LLP) was also observed and the phosphorescence lasted nearly 3 h in the light perception of the dark-adapted human eye (0.32 mcd·m^-2). Thus the LLP mechanism was analyzed.