Gd2Ti2O7:Ce粒子的表观活化能及发光性能

Gd2Ti2O7:Ce Particles’ Apparent Activation Energy and Luminescence Properties

摘要:

采用共沉淀法在不同母盐溶液浓度条件下合成出Gd2Ti2O7:Ce纳米粒子；用XRD、SEM、TG-DTA等测试手段分析了样品的物相、形貌及发光性能；用热分析动力学计算不同升温速率下的样品活化能。结果表明：前驱体在升温过程的物相变化分3个阶段，用Doyle-Ozawa和Kissinger法分别对样品初始浓度0.08mol/L和0.04mol/L条件下各阶段表观活化能计算，其平均值为42.43、145.58、381.98 kJ?mol-1和51.28、161.51、446.30kJ?mol-1，晶粒生长活化能分别为12.58 kJ?mol-1和19.54 kJ?mol-1。在0.08mol/L浓度条件下，1173K煅烧2h制备出Gd2Ti2O7:Ce纳米粒子有较高的表面活性，当铈离子掺杂0.7mol％时发光强度最大。

Abstract:

Gd2Ti2O7:Ce nanoparticles were prepared by co-precipitation method of different initial solution concentrations; The phase composition, particle morphology and luminescence properties of the samples were characterized by XRD, TG-DTA and SEM. Powders’ thermal analysis kinetics and activation energy in the synthesis process were also calculated at different heating rates. It is shown that there are three stages in the process of the precursor's phase transformations during heating, initial solution concentrations are 0.08mol/L and 0.04mol/L respectively. The average apparent activation energies of the precursors’ three reaction stages are 42.43、145.58、381.98 kJ?mol-1 and 51.28、161.51、446.30kJ?mol-1 using the Doyle-Ozawa and Kissinger methods separately. Meanwhile, the grain growth activation energies of two different concentrations are 12.58 kJ?mol-1 and 19.54 kJ?mol-1 severally. It is concluded that Gd2Ti2O7:Ce nanoparticles with higher surface activity have the best luminescence property when calcined at 1173K for 2h, especially the samples doped 0.7 mol% Ce is optimal at the concentration of 0.08mol/L.