One of the important challenges in luminescent material research nowadays is to development of new phosphors under excitation with the vacuum ultraviolet spectral region(VUV

E

>

50000 cm

-1

<

200 nm).The VUVphosphors used in mercury fluorescent tubes have high quantum efficiencies closing to 100%.Therefore

to make a noble gas discharge fluorescent tube a competitive phosphor with higher quantum efficiencies than

100

%

i.e

.more than one visible photon should be obtained per Absorbed VUV photon.This phenomenon is called quantum cutting.The goal of our research is to find an more efficient visible quantum cutter.In order to achieve this

GdF

3

:Eu

3+

nanocrystals and nanorods were synthesized by micromulsion-mediated hydrothermal process.The structure

shape and particles size were characterized by means of XRD

and TEM.VUV excitation spectra of GdF

3

:Eu

3+

nanocrystals showing that the Gd

3+

ion can absorb one VUVphoton and was excited into the

6

G

J

level

and then the

6

G

J

level relaxes to transfer the energy to Eu

3+

ion by two-step energy decaying processes

yielding two visible photons at room temperature.The visible quantum(efficiency) of GdF

3

:Eu

3+

NCs was calculated to be close to 170% by correlative transition emission peaks(intensity) ratio under VUV excitation at 160 nm.