Effect of Ytterbium and Erbium co-doped NaYF4@NaSmF4 upconversion core-shell nanoparticles on their luminescence and morphological properties

Abstract

In this study, novel upconversion (UC) core–shell NaYF4@NaSmF4 nanoparticles were synthesized via hydrothermal route which is having a tendency to convert two or more lower energy near IR photons to single higher energy UV/Visible photon for biomedical imaging and therapeutic applications. The core (NaYF4) nanoparticles were synthesized by varying sodium fluoride concentration and temperature of the reaction. The core–shell nanoparticles were prepared by growing the shell NaSmF4/NaSmF4:Yb, Er over the as-prepared core nanoparticles with optimized precursor-fluoride ratio, without any binding. The crystalline behaviour, morphology and particle size were investigated for core–shell nanoparticles using XRD, FESEM, TEM, EDS and Particle size analyzer. Photoluminescence spectra were recorded to find the emission wavelength and luminescence intensity. NaYF4@NaSmF4, the upconversion core–shell nanoparticles shown higher intensity luminescence spectra than core NaYF4. These core–shell nanoparticles have provided a platform for the spatially confining optical process, which possesses high luminescence efficiency.