Effect of Eu³⁺ Ion on the Optical and Photoluminescence Properties of Chemically Synthesized CaF₂ Nanoparticles

Abstract

Pure CaF₂ and CaF₂:Eu³⁺ nanoparticles were synthesized by solution combustion method. The structural characterization of the samples was done by XRD (X-ray diffraction). The average crystallite size for CaF₂ and CaF₂:Eu³⁺ nanoparticles was found to be 17.11 nm and 32.53 nm respectively. The surface morphology was studied by FESEM (Scanning Electron Microscope) and formation of nanospheroids was observed. The EDAX analysis confirmed the purity of the synthesized samples. The band gap energy of the samples was estimated by UV-Visible Spectroscopy. CaF₂ was found as direct band gap material of 3.87 eV and CaF₂:Eu³⁺ as indirect band gap material of 4.99 eV respectively. The photoluminescence excitation peak for CaF₂ was observed around 387 nm and the emission peak was observed around 420 nm. The photoluminescence excitation peaks for CaF₂:Eu³⁺ were observed around 299 nm, 317 nm, 361 nm and 394 nm respectively and the emission peaks were observed around 591 nm and 616 nm respectively.