Mild molten-salt synthesis and photoluminescence property of LaF3 and its white-light emission with Eu doping

Mild molten salt synthesis (MSS) method was utilized to synthesize rare earth fluorides nanocrystals with favorable fluorescence efficiency. LaF3 nanocrystals were achieved through this modified MSS method by only using La(NO3)3·6H2O and NH4HF2 as starting materials. NH4HF2 is difunctionality as both fluorine source and the flux. The effects of reaction time and temperature to the synthesis of LaF3 nanocrystals were discussed in detail. The fluorescence of LaF3 nanocrystals was detected with excitation wavelength of 360 nm, the results showed a broad band emission centered at 475 nm. The photoluminescence properties of pure LaF3 nanocrystals and Eu3+ doped samples were also investigated. In our work, white light emission was achieved in single element (Eu3+) doped LaF3 nanocrystals by adjusting the concentration of Eu3+ ions. This would be the combination of broad emission of LaF3 nanocrystals and sharp line emission of Eu3+ in the LaF3:Eu3+ nanocrystals.