SiO2包覆的β-NaYF4∶Eu3+及透明发光薄膜的制备和性能研究

通过溶胶-凝胶方法对β-NaYF4∶Eu3+进行了表面SiO2包裹处理,并将其分散于溶胶中提拉成膜,制备成发光薄膜。采用XRD、SEM、TEM、FTIR、UVPC、PL等测试手段进行了分析表征。结果表明:NaYF4表面被成功包裹上了一层SiO2,形成了核壳结构,并除去了表面油酸等有机物。表面包裹对NaYF4的晶型结构没有产生影响,但荧光性能略有下降,形貌趋向于圆形,这是由于表面SiO2颗粒在形成网络结构的张力和溶剂溶解所致。采用提拉浸渍镀膜后,发光粒子比较好地分散在薄膜上,并且具有比较理想的透过率,呈现出一定的减反射效果。由于SiO2包裹和热处理,O2-空位缺陷增强了Eu3+在420～500 nm波段的发光,这对整个发光性能是有利的。而因为能量转移,产生无辐射跃迁,613 nm处发光产生猝灭。通过实验,优化确定了制备发光薄膜的最佳工艺。

Preparation and Properties of SiO2 Coated β-NaYF4∶Eu3+ Transparent Luminescent Thin Films

β-NaYF4∶ Eu3+@SiO2 nanoparticles were prepared by sol-gel method and were dispersed in the sol to obtain luminescent thin films through dip-coating process. XRD, SEM, TEM, FTIR, UVPC and PL were used to characterized the nanoparticles and transparent films. The results indicated that the oleic-acid was removed from the nanoparticles and SiO2 was coated on the particles successfully. The SiO2 shell has no influence on the crystalline structure and its fluorescence perfor-mance declines slightly. The morphology of β-NaYF4∶Eu3+ transforms to nanospheres due to the solvent solution and tension of network structure of SiO2. The nanoparticles were dispersed in the thin films uniformly, and the films also have good transmittance and minus reflection effect. After coating and thermal treatment, the luminescence intensity from 420 to 500 nm was enhanced owing to the oxygen vacancy. But the luminescence at 613 nm quenches because of the energy transfer and nonradiative transition. The optimal technological parameters of the films were obtained by testing.