The Synthesis of Nanophosphors YPxV1–xO4 by Spray Pyrolysis and Microwave Methods

Abstract

Due to rare earth doping, phosphates and vanadates are the leading materials for the synthesis of phosphors due to their thermal stability, low sintering temperature, and chemical stability. Phosphors in the nanoscale state are of particular interest. The simple, fast, and scalable synthesis of nanophosphors with high chemical homogeneity is a priority task. The purpose of this work was to synthesize powders of mixed yttrium vanadate-phosphate crystals of various compositions by coprecipitation under the action of microwave radiation and spray pyrolysis, as well as to compare the characteristics of the obtained samples. Samples of YVхP1–хO4 of different compositions were synthesized by coprecipitation under the action of microwave radiation and spray pyrolysis in different modes. In the case of the synthesis of yttrium vanadate-phosphate YVхP1–хO4 by spray pyrolysis followed by annealing, according to the X-ray phase analysis data, single-phase nanopowders were formed. The morphological characteristics of the samples were revealed by the methods of transmission electron microscopy and scanning electron microscopy. Depending on the annealing conditions, the samples were either faceted or spherical particles less than 100 nm in size. The composition of the YVхP1–хO4 , samples synthesized by the coprecipitation method under the action of microwave radiation strongly depended on the pH of the precursor solution. The minimum content of impurity phases was reached at pH 9. Spray pyrolysis allows the synthesis of yttrium vanadate phosphate YVхP1–хO4 nanopowders of high chemical homogeneity with a particle size of less than 100 nm. The maximum chemical homogeneity of yttrium vanadate-phosphate powders was achieved at pH = 9 during the synthesis of YVхP1–хO4 by coprecipitation under the action of microwave radiation. However, the particle size dispersion was large, within the range of 2–60 μm.

Keywords

• phosphors
• microwave synthesis
• spray pyrolysis
• nanopowders
• yttrium vanadate-phosphate