A molecular precursor approach to monodisperse scintillating CeF3 nanocrystals

Abstract

A series of anhydrous cerium(III) trifluoroacetate complexes with neutral O-donor ligands, namely Ce₂(OAc)(TFA)₅(DMF)₃ (1), Ce(TFA)₃(L)_x [x = 2, L = THF (2), DMF (3), DMSO (4); x = 1, L = diglyme (5)] and Ce₂(TFA)₆(DMSO)_x(DMF)_y [x = 6, y = 0 (6); x = 4, y = 2 (7)] (where OAc = acetate, TFA = trifluoroacetate, THF = tetrahydrofuran, DMF = dimethylformamide, DMSO = dimethylsulphoxide, and diglyme = MeO(C₂H₄O)₂Me] were synthesized and completely characterized by elemental analysis, FT-IR spectroscopy and TG-DTA-MS studies. A partially hydrated complex [Ce(TFA)₃(diglyme)(H₂O)] (8) was obtained by slow evaporation of the THF solution of anhydrous 5 in the air. The single crystal X-ray diffraction analysis of 1, 3, 4, and 6–8 showed the versatile bonding mode of the TFA ligand (terminal, chelating and bridging). These complexes, on decomposition in 1-octadecene in inert atmosphere, gave CeF₃ nanoparticles of 8–11 nm size. The complex 5 proved to be the best precursor in the series because of the ability of the diglyme ligand to act as capping reagent during decomposition to render the CeF₃ particles monodisperse in organic solvents. The obtained CeF₃ nanoparticles were characterized by FT-IR, EDX analysis and TEM studies and their luminescence and scintillation responses under UV and X-ray excitation were studied and compared with that of CeF₃ single crystal.