Near-infrared Emission of Redispersible Er³⁺, Nd³⁺, and Ho³⁺ Doped LaF₃ Nanoparticles

TLDR

Nonradiative decay probabilities differ between surface and core ions in LaF₃ nanoparticles. LaF₃ nanoparticles doped with Eu, Er, Nd, and Ho were synthesized and are dispersible in organic solvents. Eu³⁺ occupies La³⁺ sites, shows biexponential decay with lifetimes of 7.7 ms and 2.9 ms indicating high quantum yields, and Er, Nd, and Ho doped particles emit in the telecom window (1530 nm, 1330 nm, 1450 nm).

Abstract

Nanoparticles of LaF3 doped with Ln3+ (Ln = Eu, Er, Nd, and Ho) have been prepared that are dispersible in organic solvents. From the spectrum of Eu3+ it has been concluded that the dopant ion occupies a La3+ site. The luminescence decays are fitted biexponentially. A given possible explanation for this is a different probability of nonradiative decay for ions at or near the surface and ions in the core of the particles. The lifetimes of Eu3+ luminescence at a doping concentration of 5% were 7.7 ± 0.2 and 2.9 ± 0.2 ms, indicative of very high quantum yields. The particles doped with Er3+, Nd3+, and Ho3+ are promising materials for polymer-based optical components, because they show luminescence in the telecommunication window (i.e., Er3+ at 1530 nm, Nd3+ at 1330 nm, and Ho3+ at 1450 nm).