Preparation and luminescent properties of CaF2:Ln3+ (Ln:Er,Er/Yb)/Nafion composite films

In this work, CaF₂:Ln³⁺ (Ln:Er,Er/Yb)/Nafion composite films were prepared using Nafion as modifications and matrices by dripping method. The composite films were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Composite films are transparent and CaF₂:Ln³⁺ (Ln:Er,Er/Yb) nanoparticles are well dispersed in Nafion films. The thicknesses of CaF₂:Er³⁺/Nafion and CaF₂:Er³⁺,Yb³⁺/Nafion composite film are about 77 and 73 μm, respectively. The nanoparticles in composite film possess cubic phase. CaF₂:Er³⁺,Yb³⁺/Nafion composite film has stronger characteristic emission of Er³⁺ around 1530 nm with full width at half-maximum (FWHM) of 73 nm and longer luminescence lifetimes of 22.04 μs (25.03%) and 100.77 μs (74.97%).