GdVO_4:Eu^(3+)的热释光研究

Thermoluminescence of GdVO_4: Eu^(3+)

GdVO_4:Eu^(3+)有着十分优良的发光特性,它发光强度高,特别是具有很好的温度特性,在室温以上发光强度随温度的升高而增强,很利于在高温下使用此材料。本文对它的热释光进行了研究,其热释光峰值分别位于193,235和304K,根据计算可知它们的陷阱深度分别为0.39,0.47和0.61eV。陷阱的主要来源可能是F+,F和钒空位;Eu3+掺入导致的晶格畸变,其中最主要的来源可能是空位导致的。

GdVO4:RE3+ is a significant red-emitting material with a main emission peak at 619nm.The luminescence intensity of GdVO4:Eu3+ is in the same order as that of YVO4:Eu3+. GdVO4:Eu3+ has good temperature properties and higher quenching temperature than that of YVO4: Eu3+, so it is very suitable for application in high temperature environment such as high-pressure mercury-vapor lamps. Usually, there are so many defects and traps in solids. Thermoluminescence(TL) is a useful tool to provide us with the information of solid defects and traps. The thermoluminescence of GdVO4:Eu3+ range from 100K to 500K was detected. The sample was excited by X-ray at the temperature of 90K. The velocity of rising temperature is 0.5K/s. The result shows that there are three main TL bands peaked at 193, 253 and 304K. The trap parameters are obtained from the TL curves. The trap depth is 0.39, 0.47 and 0.61eV , respectively. The origination of traps has three possibilities. Firstly, the color centers such as F centers and F+ centers as a result of the volatilization of V2O5 during preparation can form trap level in the forbidden band. The second, when Eu3+ is doped into host and enter into Gd3+ sublattice , the distortion of the lattice also can form trap level. Finally, because the sample is powder, there is many surface states which can form traps, too. Above all, the most possible reason maybe the color centers.