Nucleation and Growth of Monodisperse Hexagonal NaYF4 Nanoparticles Synthesized by Trifl uoroacetate Precursors Thermolysis

Synthesis process conditions for NaRF4 (R – rare-earth elements) nanoparticle production with specified structural and dimensional characteristics have been optimized by manipulating the technological parameters of the trifluoroacetate precursors thermolysis: temperature, duration of the experiment and composition of the reaction medium. The temporary and thermal parameters of NaRF4 nanoparticles growth from the nucleation stage to the formation of final nanocrystals have been analized with the direct sampling method. Limiting factors in the nanoparticles synthesis in both cubic and hexagonal polymorphic phases have been identified by transmission electron microscopy in detail. The key role of the heating rate of the reaction mixture at the initial synthesis stage on the structural and morphological characteristics of this type nanoobjects formation is demonstrated. The features of the phase transformation of nanoparticles from the metastable α-phase to the stable β-phase during thermolysis process are discussed.