Selective synthesis and luminescence properties of nanocrystalline GdF3:Eu 3+ with hexagonal and orthorhombic structures

GdF3:Eu3+ nanophosphors with hexagonal or orthorhombic structure have been succeeded to be selectively synthesized at room temperature for the first time via a simple soft chemical route. The structure and morphology of GdF3:Eu3+ nanophosphors were controlled by using different fluoride precursors. Hexagonal GdF3:Eu3+ nanocrystals were formed when NaBF4 was used as a fluoride precursor, while orthorhombic GdF3:Eu3+ nanocrystals were obtained with NaF or NH4F fluoride precursor. It was also experimentally revealed that hexagonal GdF3:Eu3+ nanophosphors emitted essentially stronger Eu3+ luminescence than orthorhombic ones did. The formation mechanism of GdF3 nanocrystals and the possible reasons of the strong PL in hexagonal were discussed.