Abstract:
Nanophosphors LaF
3:Eu
3+ with hexagonal structure have been prepared by hydrothermal method.The properties of the resulting phosphors are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), photoluminescence (PL) spectra and decay curve.The excitation spectra of LaF
3:Eu
3+ phosphors are mainly consists of the band at about 250 nm that corresponding to O
2-→Eu
3+ charge-transfer (CT) and some sharp lines of Eu
3+ f-f transitions in the near ultraviolet region with one intense peak at about 396 nm.The emission spectra were used to probe the local environments of Eu
3+ ion in LaF
3 crystal.Based on the emission and excitation spectra at 298K, it is identified that the lattice site of Eu
3+ in tetragonal LaF
3 nanocrystals descending from
D4h to approximate
C2v as a result of the lattice distortion.Under the 396 nm excitation, strong red emission peaked at 591 nm attributed to
5D
0→
7F
1 transition of Eu
3+ are observed for 10 % LaF
3:Eu
3+ phosphors as the optimal doping concentration.The luminescence properties show that LaF
3:Eu
3+ phosphor may be considered to be a potential red phosphor candidate for near-UV light emitting diodes (LEDs).