Gd_2O_3:Eu纳米晶的制备及其光谱性质研究

Preparation of Nanocrystal Gd_2O_3: Eu by EDTA Complexing Sol-Gel Process and Spectroscopic Study

以EDTA为络合剂,聚乙二醇为有机分散剂,用络合溶胶-凝胶法制备出Gd_2O_3:Eu纳米晶。用XRD,SEM,X-射线能量色散谱仪(EDS),荧光分光光度计等分析手段对Gd_2O_3:Eu的纳米晶结构、形貌、组分的均匀性以及发光特性进行了研究。结果表明:EDTA-M凝胶仅在800℃焙烧即可得到颗粒细小、组分均匀、纯立方相的Gd_2O_3:Eu纳米晶,颗粒基本呈球形,粒径为30nm左右。对样品的激发光谱、发射光谱测定表明:Gd_2O_3:Eu纳米晶在269nm光激发下发红光,发射光谱谱峰在611nm,与体材料基本相同;激发光谱中电荷迁移带(CTB)明显红移,从体材料的255nm移至269nm,移动了约14nm;猝灭浓度从体材料的6％提高到8％。

Gd2O3: Eu nanocrystal was synthesized by EDTA complexing sol-gel process at relatively low temperature, in which ethyl -ene-diamine-tetraacetic acid (EDTA) and polyethylene glycol (PEG) were used as the chelating agent and disperser respectively. The properties of the nanocrystal were investigated by XRD, SEM, EDS, and fluorescence spectrophotometer. The results show that nanosized, homogenous and pure cubic phase Gd2O3: Eu has been produced after the precursor calcined at 800℃ for 2 h. The particles of the Gd2O3 : Eu are basically spherical in shape and about 30 nm in size. The main emission peak of Gd2O3: Eu nanocrystal is at 611 nm, resulting in a red emission. Compared with micron scale Gd2O3 : Eu phosphors prepared by a conventional method, a clear red shift occurs in the excitation spectrum of Gd2O3 : Eu nanocrystal prepared by the present work, and the quenching concentration of Eu has been raised. For this type of nanophosphor, quenching starts at an Eu concentration of 8% (mol%), while a value of 6% was obtained for the conventional one.