Luminescence properties of Eu3+:NaGd(WO4)2 nanoparticles and nanorods

The effect of Eu3+ and Gd3+ co-doping on the morphology and luminescence of NaYF4:Eu3+, Gd3+ phosphors

Eu³⁺ and Gd³⁺ doping results in the size reduction of β-NaYF₄: Eu³⁺, Gd³⁺ microparticles; Gd³⁺ co-doping enhances the luminescence intensity.

Highly Efficient Transparent Nanophosphor Films for Tunable White-Light-Emitting Layered Coatings

Bright luminescence in rare-earth (RE) nanocrystals, the so-called nanophosphors, is generally achieved by choosing a host that enables an effective excitation of the RE activator through charge or energy transfer. Although tungstate, molybdate, or vanadate compounds provide the aforementioned transfer, a comparative analysis of the efficiency of such emitters remains elusive. Herein, we perform a combined structural and optical analysis, which reveals that the tetragonal GdVO₄ matrix gives rise to the highest efficiency among the different transparent nanophosphor films compared. Then, we demonstrate that by a sequential stacking of optical quality layers made of Eu³⁺- and Dy³⁺-doped nanocrystals, it is possible to attain highly transparent white-light-emitting coatings of tunable shade with photoluminescence quantum yields above 35%. Layering provides a precise dynamic tuning of the chromaticity based on the photoexcitation wavelength dependence of the emission of the nanophosphor ensemble without altering the chemical composition of the emitters or degrading their efficiency. The total extinction of the incoming radiation along with the high quantum yields achieved makes these thin-layered phosphors one of the most efficient transparent white converter coatings ever developed.

Europium-doped NaGd(WO4)2 nanophosphors: synthesis, luminescence and their coating with fluorescein for pH sensing

Uniform nanospheres of Eu : NaGd(WO₄)₂ have been synthesized and further coated with fluorescein to develop a ratiometric pH sensor for biotechnological applications.