Gd_2O_3:Eu透明厚膜的制备及其发光特性

以无机稀土氧化物为原料、2-甲氧基乙醇为溶剂、PVP为胶粘剂、PEG200为有机分散剂,采用溶胶-凝胶工艺成功制备出Gd2O3∶Eu3+透明闪烁薄膜。通过2次涂复,薄膜厚度达到了1.5μm,膜层均匀、无散射颗粒、无裂纹,可见光区的透射率约为80%。研究表明PVP在厚膜烧结过程中可以松弛膜的结构、减小应力的出现,避免厚膜开裂,同时还可以提高溶胶的粘度,在厚膜制备中起到了关键作用。此外,我们还研究了Gd2O3∶Eu3+闪烁薄膜的激发、发射和发光衰减时间谱,结果表明,该薄膜发光性能优良,可初步满足X射线成像用闪烁薄膜的要求。

Preparation and Luminescence Properties of Transparent Gd_2O_3:Eu Thick Film

High-resolution X-ray imaging systems require materials with good scintillation performances,especially X-ray absorption performance.Compared with powder phosphors display devices,those with transparent crystalline phosphors are very interesting due to their higher contrast and resolution for having no optical scattering,superior thermal conductivity as well as high degree of uniformity and better adhesion.Europium-doped gadolinium oxide is a promising candidate due to its high density (7.62 g·cm~(-3)),good light yield (18.5×10~3 photons/MeV),and the red emission of Eu~(3+) ion.The sol-gel method is one of the most important techniques for deposition of functional films,because it possesses a number of advantages over conventional film formation techniques,such as low processing temperature,easy coating of large surfaces,and homogenous multicomponent oxide films.In X-ray imaging application,the thickness of the film is the most important factor for commercial use,which can increase X-ray absorption of the film and then strengthen its luminescence yield.In the present work,transparent Gd_2O_3:Eu~(3+) thick film was successfully prepared using sol-gel method and spin-coating technique by choosing Ln_2O_3 (Ln=Gd,Eu) as raw materials,2-methoxyethanol as solvent,PVP as adhesive and PEG200 as surface modifier.The film was homogeneous and crack free.The thickness of the film could achieve 1.5 μm after 2 times of coating,and its transmittance was approximately 80% in visible region.It was shown that PVP played an important role in film preparation,which could suppress stress and increase viscidity of the sol.In addition,the cxcitation,emission and decay time of the Gd_2O_3:Eu~(3+) scintillator film were studied.Their performances were quite good,which implied that the film would have promising applications in high-spatial-resolution X-ray imaging and flat panel display devices.