The luminescence properties of nanosized lanthanide oxide materials have attracted extensive interest because of their fundamental and technological importance.Gd

2

O

3

which is easily obtained due to abundant resource in nature

has been widely used as host material.The emission efficiency of Sm

3+

associated with the intra-4f-shell transition is very high

and it earl emit bright light under both ultraviolet and infrared excitation.Therefore

it often plays a very important role in many luminescent materials.In this paper

Gd

2

O

3

:Sm

3+

and Li

+

-doped Gd

2

O

3

:Sm

3+

nanocrystals were prepared by a combustion method.The pure nanocrystals were obtained after annealing at 800℃

and the crystallinity was improved with increasing annealing temperature.Both Gd

2

O

3

:Sm

3+

and Li

+

-doped Gd

2

O

3

:Sm

3+

nanocrystals appeared to be cubic crystal-line phase according to the XRD results.In contrast to Gd

2

O

3

:Sm

3+

which showed an irregular shape of ag-glomerated fine particles

the morphology of Li

+

-doped Gd

2

O

3

:Sm

3+

nanocrystals were spherical and quite regular.These particles were measured to be about 50 nm in diameter.When excited at 275 nm and 980 nm

Gd

2

O

3

:Sm

3+

and Li

+

-doped Gd

2

O

3

:Sm

3+

nanocrystals exhibit similar emission spectra

which consist of the characteristic emission bands of the Sm

3+

ions (

4

G

5/2

6

H

J

J

=5/2

7/2

9/2 transitions at 560

602

650 nm in the spectra) due to an efficient energy transfer from the Gd

2

O

3

host lattice to the doped Sm

3+

ions.It was found that the incorporation of Li

+

into the Gd

2

O

3

:Sm

3+

nanocrystals has greatly enhanced the photolumi-nescence intensity of Sm

3+

in both photoluminescence and upconversion emission.The highest emission inten-sity was observed with Gd

1.83

Li

0.15

Sm

0.02

O

3

whose brightness was increased by a factor about 7.0 in comparison with that of Gd

2

O

3

:Sm

3+

.As we all known that defects of the surface of the nanoparticles

which provide non-radiation recombination routes for electrons and holes

often act as non-radiative centers and has great influence on luminescent properties.It can be suggested that the incorporation of Li

+

can greatly decrease the deficiencies and oxygen vacancies.That is

the defects and oxygen vacancies of the surface of nanoparticles decreased at first when Li

+

content was lower

which decreased the luminescence quenching centers and increased the crystallinity

thereby enhanced the emission intensity.A lot of defects could be induced in the system with a gradual increase of Li

+

content.This will destroy the crystallinity and thus lead to the luminescence quenching.In conclusion

this paper reported the correlation between the morphology

structure and optical behaviors on Gd

2

O

3

:Sm

3+

nanocrystals doped with Li

+

Li

+

doping at a low content significantly improved the morphology of phosphors and strongly enhanced the luminescent properties.