Synthesis of Luminescent ZrO₂:Eu³⁺ Nanoparticles and Their Holographic Sub-Micrometer Patterning in Polymer Composites

Graphical Abstract

Highly crystalline, fluorescent ZrO₂:Eu³⁺⁺ nanoparticles with luminescence quantum yield of up to 8.7% are synthesized in a facile and one-step procedure. Through holographic photopolymerization of dispersions of the nanoparticles in suitable monomer mixtures, volume Bragg gratings with light-emissive properties are fabricated, evidencing the high suitability of this approach for the synthesis of tailored nanomaterials for elaborate and demanding applications.

Abstract

Here, the facile synthesis of fluorescent ZrO₂:Eu³⁺ nanoparticles with luminescence quantum yield of up to 8.7% that can be easily dispersed in organic solvents and utilized for the preparation of organic/inorganic volume holographic gratings is presented. The nanoparticles are prepared through a one-step solvothermal process resulting in spherical particles with a mean size of 4 nm that were highly crystalline directly after the synthesis, without any need for calcination treatment. Detailed luminescence studies of the nanoparticles as a function of Eu³⁺ content demonstrate that the dopant concentration and its site symmetry play an important role in the emissive properties and lifetime of the luminescent centers. It is shown that the luminescence quantum yield of the colloidal ZrO₂:Eu³⁺ nanoparticles increases with dopant concentration up to a critical concentration of 11 mol% while the luminescence lifetime is shortened from 1.8 to 1.4 ms. Holographic photopolymerization of suitable monomer mixtures containing the luminescent nanoparticles demonstrated the ability to inscribe volume Bragg gratings (refractive index contrast n₁ up to 0.011) with light-emissive properties, evidencing the high suitability of this approach for the fabrication of tailored nanomaterials for elaborate and demanding applications.