As the rapid development of high-energy physics and nuclear medical technology

there has been a great growth of interest in lutetium-based compounds such as lutetium silicate

lutetium aluminate and lutetium oxide.High

Z

number(

Z

=71) of Lu

high physical and chemical stability and high luminescent efficiency of these compounds make them extremely attractive for application in scintillator materials

especially in medical applications.Nanocrystalline Lu

2

O

3

:Tb was prepared by combustion synthesis.X-ray diffraction(XRD) spectra

high-resolution electronic microscope(HREM) photographs

Fourier transform infrared spectroscopy(FT-IR)

excitation and emission spectra

as well as fluorescent decay curves were measured to characterize the structure and luminescent properties of the samples. The results show that the compound of composition Lu

2

O

3

crystallizes in pure cubic structure.By changing the ratio of glycine to nitrate in the combustion process

the particle size can be controlled in the range from 40 nm to 3nm

and the amorphous area increases while the grain size decreases

which plays an important role in the luminescence properties.Photoluminescence spectra and fluorescent decay curves measured under room temperature show typical excitation and emission peaks of Tb

3+

.Under UVexcitation

the relative intensity of

5

D

3

7

F

J

increases with the decreasing of particle size because of the weakened cross-relaxation process in small-size samples.In the sample smaller than 10nm

the efficiency of energy transfer from host lattice to the activator ions decreases sharply

and there presents a new decay composition of 0.63 ms for the

5

D

4

energy level

besides the normal one is about 1.9 ms.