水热-还原法合成球形Gd_2O_2S:Pr^(3+)闪烁体粉末

Synthesis of Spherical Gd_2O_2S:Pr^(3+) Scintillator Phosphors by Hydrothermal-reduction Method

采用Gd2O3、Pr6O11、H2SO4和尿素为实验原料,通过水热-还原法合成了Gd2O2S:Pr3+闪烁体粉末。利用X射线衍射(XRD)、红外光谱(FT-IR)、热重分析(DTA-TG)、扫描电子显微镜(SEM)和光致发光(PL)光谱等手段对合成的粉末进行了表征。研究表明尿素与Gd2(SO4)3的摩尔比(m)对前躯体的物相组成和形貌有很大影响,最佳的m值为2.5。最佳的前躯体在流动的90%Ar+10%H2气氛中800℃煅烧1 h能转变成单相的Gd2O2S粉末。所获得的Gd2O2S粉末呈球形,分散性良好,粒径尺寸约为1μm。在307 nm的紫外光激发下,Gd2O2S:Pr3+闪烁体粉末的主发射峰位于516 nm,归属于Pr3+的3P0-3H4跃迁。在Gd2O2S基质中,Pr3+的猝灭浓度为1%(摩尔分数),猝灭机理为电偶极-电四极相互作用引起的。

Hydrothermal-reduction method for synthesizing spherical Gd2O2S： Pr^3＋ scintillator phosphors was developed by using Gd2O3,Pr6O11,H2SO4 and urea as the starting materials. The characterizations of Gd2O2S： Pr^3＋ scintillator phosphors were investigated by means of XRD,FT-IR,DTA-TG,SEM and PL spectra. The results indicates that the phase and morphologies of the precursors are strongly dependent on m value,namely,the molar ratio of urea to Gd2（SO4）3. The optimal m value is 2. 5. Pure spherical shaped Gd2O2 S particles can be synthesized by calcining the optimal precursor at 800 ℃ for 1 h in flowing 90% Ar ＋ 10% H2 atmosphere. The pure Gd2O2 S phosphor particles are spherical in shape and well dispersed,with particle size of about 1 μm. Photoluminescence spectra of Gd2O2S： Pr^3＋under 307 nm UV light excitation show a green emission at 516 nm as the most prominent peak,which corresponds to the^3P0-^3H4 transition of Pr^3＋ ions. The quenching concentration of Pr^3＋ ions is 1mol% and the concentration quenching mechanism is the electric dipole-quadrupole interaction for the ^3P0→^3H4 transition of Pr^3＋ions.