Synthesis, spectroscopic and structural studies on YOF, LaOF and GdOF nanocrystals doped with Eu3+, synthesized via stearic acid method

• Optimal conditions for the synthesis of ROF:Eu3+ (RE = Y, La, Gd) were found.
• Effectiveness of the Eu3+ luminescence intensity and energy transfer were examined.
• Efficient luminescence of GdOF with a high quantum yield of 73% was observed.
• Judd–Ofelt theory was used to investigate properties of prepared nanomaterials.

Nanocrystalline Eu3+ doped REOF oxofluorides (where RE = Y, La, Gd) were synthesized using stearic acid as the reaction medium. Optimal conditions for the synthesis of pure and single-phased oxyfluorides were found. The obtained products were analysed using thermogravimetric analysis, X-ray analysis, transmission electron microscopy and the Rietveld method. The influence of calcination temperature on the physicochemical properties was studied. Spectroscopic properties of the tetragonal and rhombohedral oxyfluoride nanocrystals were investigated using excitation and emission spectra and luminescence lifetime measurements. Effectiveness of the Eu3+ dopant red emission intensity and energy transfer processes were examined in relation to the structure and the presence of the RE ion in oxyfluorides studied. The highest luminescence efficiency was observed for the GdOF:Eu3+ nanomaterial. Judd–Ofelt intensity parameters were calculated and analysed.