Efficient Luminescence from Rare‐Earth Fluoride Nanoparticles with Optically Functional Shells

Abstract

Rare‐earth fluorides are a class of materials with considerable potential in optical applications. Fluoride lattices typically permit high coordination numbers for the hosted rare‐earth ions, and the high ionicity of the rare‐earth‐to‐fluorine bond leads to a wide bandgap and very low vibrational energies. These factors make rare‐earth fluorides very useful in optical applications employing vacuum ultraviolet and near‐infrared excitation. The preparation of nanometer‐sized particles has opened the door for new properties and devices if the performance of their macroscopic counterparts can be conserved in the nanometer regime. However, at small particle sizes, defect surface states and adhering water reduce the optical efficiency. These shortcomings can be reduced by applying protective shells around the luminescent cores, which can also be involved in the luminescent process.

The angular overlap model extended for two-open-shell f and d electrons

“…Because we are often confronting with low site symmetry of the lanthanide coordination obtained from the experimental synthesis of modern phosphors, [33][34][35] In the AOM formalism, each ligand is assigned with parameters e s , e p , e d and e j classified according to its overlap with the lanthanide ion to give a s, p, d and j bond, respectively. In Fig.…”

A Simple Reducing Approach Using Amine To Give Dual Functional EuSe Nanocrystals and Morphological Tuning

“…[4][5][6] Host matrices used in these materials usually were Ln 3+ ions, [7][8][9][10] but it was problematic to prepare low-valent lanthanide materials on nano-meter scales. [11] Low-valent lanthanide mono-chalcogenide nanocrystals (NCs), and especially stable europium mono-chalcogenide EuX (X = O, S, Se, and Te) NCs started to become available with appealing optical and magnetic properties.…”

One‐Pot Synthesis of Luminescent Polymer‐Nanoparticle Composites from Task‐Specific Ionic Liquids

“…Here, this asymmetry ratio is found to vary only slightly from one sample to another, being close to 1 in each case ( Figure S8, Supporting Information), in agreement with previous results for Eu 3 + in the hexagonal-phase fl uoride system. [ 18,21,32 ] The measured powder XRD patterns of the isolated EuF 3 and GdF 3 :Eu 3 + particles are shown below in Figure 2 a, and TbF 3 and GdF 3 :Tb 3 + in Figure 2 b. These are compared to the database patterns for LnF 3 both in the tysonite type hexagonal structure (JCPDS 32-373) and in the orthorhombic YF 3 -type structure (JCPDS 12-788).…”