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.