Mechanosynthesis, Structure and Photoluminescent Properties of the Pr3+ Doped LiNbO3, LiNbO3:Mg, LiTaO3 Nanopowders

Abstract

In the current work, nanocrystalline powders with different compositions, namely Li0.98Pr0.02NbO3, Li0.93Pr0.02Mg0.05NbO3 and Li0.98Pr0.02TaO3 were synthesized for the first time using the method of high-energy ball milling of the starting materials (Li2CO3, Nb2O5, Ta2O5, MgO, Pr6O11), followed by high-temperature annealing. XRD data analysis confirmed the absence of parasitic phases in the obtained nanocrystalline compounds. The estimated particle sizes ranged from 20 to 80 nm. From the obtained nanopowders, ceramic samples were prepared using specially developed equipment, which allowed for pressing at elevated temperatures with a simultaneous application of a constant electric field. The obtained photoluminescence spectra exhibit characteristic features of Pr3+ ions in the crystal structure of LiNbO3 and LiTaO3 and are most efficiently excited by UV light. Samples pressed with an electric field application show higher intensity of photoluminescence. Investigations of the temperature dependence of electrical conductivity of the Li0.98Pr0.02NbO3 sample, pressed with the application of an electric field, indicate that the conductivity mechanism is similar to that of LiNbO3 single crystals and, at high temperatures, is attributed to the lithium conduction mechanism.

Vacuum-assisted colossal enhancement of up-conversion luminescence of lanthanide-doped nanoparticles upon NIR laser irradiation – a new strategy for phosphor development

“…3,[21][22][23][24][25][26][27] On the other hand, there are also physical approaches such as mechanosynthesis in a ball mill, (nano)lithography, laser-ablations, high-temperature evaporation, and so forth. 3,24,25,28,29 Each of these techniques has benefits and drawbacks, and ultimately the choice of the most suitable technique depends on the specific requirements of the material being produced. 24,25,30,31 For example, the solgel technique is a versatile method for producing nanomaterials with high crystallinity, high surface-to-volume ratio and controlled porosity.…”

Rare-Earth Ion Loss of Er- or Yb-Doped LiNbO3 Crystals Due to Mechanical Destructive Effect of High-Energy Ball Milling

“…For developing a well-defined and reliable method to produce particles with a diameter of about 10 nm containing the rare-earth dopant(s) in a predetermined concentration and in such a dilute form so that the optically active atoms are far enough from each other to behave as non-interacting optically active centers, mechanical grinding seems to be ideal. Pure and Pr 3+ doped LN monocrystalline powder has already been produced by high-energy ball milling in a mechanochemical way starting from oxides and followed by high-temperature treatment [26,27]. It is also a simple and relatively fast method for producing nanomaterials from macro range (top-down method) with high yield without introducing pollutants into the system, and by using distilled water as medium (wet milling process), the aggregation of the nanocrystals can be avoided.…”