Morphology and optical properties of CeF3 and CeF3:Tb nanocrystals: The dominant role of the reaction thermal mode

Abstract

Quite recently, nanosized rare-earth (RE) fluorides have been gaining importance due to their ability to form nanocomposites that are capable to absorb ionizing radiation. The efficiency of these materials may vary under the influence of external factors and under the growing conditions of nanocrystals. In this paper a novel effective approach to the synthesis of CeF3 nanocrystals (NCs) with a high yield of the desired material was proposed. The developed approach allows different modifications within the synthesis, thereby making it possible to change the growth conditions of QDs. The main exchange reaction between cerium oleate and ammonium fluoride was carried out in a non-coordinating solvent 1-octadecene (ODE) diluted with an excess of oleic acid (OA). The influence of the reaction temperature on the nucleation and the formation of a nanocrystals was presented. The possibility of introducing Tb3+ (1-5%) into nanosized CeF3 at one of the lowest reaction temperatures (180 degrees C) was also studied. The introduction of Tb3+ into the CeF3 crystal lattice led to changes in the nanocrystal's structure, an increase in their size and also to the expected changes in the photoluminescence (PL) spectra. The prepared CeF3 and CeF3:Tb QDs were well dispersible in low-polar media, which makes them promising candidates for the role of active agents or wavelength shifters in the matrix of polymer scintillators.