Synthesis of triple-doped core/shell/shell upconversion nanoparticles

Abstract

Abstract A novel triple-doped core/shell/shell NaGdF 4 /NaGdF 4 :Yb, Tm,Nd/NaGdF 4 upconversion nanoparticles(UCNPs) has been designed and synthesized by thermal decomposition. Yb 3+ and Nd 3+ were used as sensitizers and Tm 3+ with multi-level was activators. Three-layout nanoparticles exhibits 1.5 times strong emission than two-layout structure. The UC spectrum exhibits two bands centered at 525–535 and 578–585 nm from Nd 3+ , corresponding to 4 G 7/2 – 4 I 9/2 and 4 G 7/2 – 4 I 11/2 transitions after excitation at 800 nm. These nanocrystals are promising an attractive luminescent biomarkers for biological and magnetic resonance imaging.