In recent years

the borate luminescence materials have received much attention owing to their low synthetic temperature and high luminescent efficiency. In order to search for the new luminescent material

the synthesis and luminescence properties of Na

3

(La

1-x

Sm

x

)

2

(BO

3

)

3

(

x

=0～0.10) were firstly reported in this paper. The samples in polycrystalline form were synthesized by the conventional solid state reaction. The mixture of Na

2

CO

3

La

2

O

3

Sm

2

O

3

and H

3

BO

3

with an excess of 5 mol% were preheating at 500℃ for 10 hours

then sintered 24 hours at 720～750℃for Na

3

(La

1-x

Sm

x

)

2

(BO

3

)

3

(

x

=0.005～0.10)

and 935℃ for Na

3

La

2

(BO

3

)

3

. In the course of experiment

the purity of all samples was checked by X-ray diffraction (XRD). The single phase powder of Na

3

(La

1-x

Sm

x

)

2

(BO

3

)

3

in range of 0.0～1.0mol% were obtained when repeated heat treatment caused no further changes in the X-ray powder diffraction patterns. X-ray diffraction analysis shows that all these compounds are isomorphous with Na

3

La

2

(BO

3

)

3

which belongs to orthorhombic systems

space group

Amm

2. This indicats that the La

3+

ions(

r

=0.105nm) in Na

3

La

2

(BO

3

)

3

can be partly replaced by the smaller rare earth ions Sm

3+

(

r

=0.096nm) without change of crystal structure. The infrared spectra of the compounds Na

3

La

2

(BO

3

)

3

(a)

Na

3

(La

0.995

Sm

0.005

)

2

(BO

3

)

3

(b) and Na

3

(La

0.94

Sm

0.06

)

2

(BO

3

)

3

(c) scanned between 400～2000cm

-1

in the transmittance mode were measured. The results were in agreement with the characteristic values of the BO

3

3-

groups. The minor difference observed in the infrared spectra of (b) and (c) at 450～550 cm

-1

might be due to the changes in the Sm and La ions and their ionic radii. The luminescent properties of Sm

3+

in Na

3

La

2

(BO

3

)

3

host were investigated by the excitation and emission spectra at room temperature. The emission spectrum obtained for Na

3

La

2

(BO

3

)

3

:Sm

3+

under 400nm excitation at room temperature in range of 500～750nm was shown in Fig.2(a). There were four main emission peaks at near 564

599

645 and 707nm

among which the intensity of the 599nm line was the highest. These emission peaks were all narrow sharp peak not broad bands. They originated from the f f transitions of Sm

3+

ions 4f electrons

which assigned to

4

G

5/2

4

H

5/2

transition between 550～570nm

4

G

5/2

6

H

7/2

transitions between 580～610nm

4

G

5/2

6

H

9/2

transition between 630～655nm and

4

G

5/2

6

H

11/2

transitions between 700～710nm

respectively. They belonged to the characteristic emission of Sm

3+

ions. The excitation spectrum for Sm

3+

599nm emission recorded at room temperature showed lines corresponding to transitions

6

H

5/2

(4K

4L)

17/2

(345nm)

6

H

5/2

(4D

6P)

15/2

(362nm)

6

H

5/2

4

L

17/2

(375nm)

6

H

5/2

4

K

11/2

(400nm)

6

H

5/2

4

M

19/2

(

6

P

4

P)

5/2

(418nm)

and

6

H

5/2

4

I

13/2

(

4

I

9/2

)(475nm). As we can see in Fig.2(b). The intensity of the transition at 400nm was found to be the highest in all the spectra. It showed that the strongest fluorescence emission at 599nm could be obtained under 400nm excitation. At room temperature

the emission spectra of Na

3

(La

1-x

Sm

x

)

2

(BO

3

)

3

at different concentration were recorded by the excitation of 400nm. The relative peak heights can change with the concentration of Sm

3+

while the peak positions remain practically unchanged. The relationship between fluorescent intensities of 599nm emission peak of Sm

3+

and act ive rare earth ion concent rat ions in Na

3

(La

1-x

Sm

x

)

2

(BO

3

)

3

was described in Fig.4.It shows that Sm

3+

luminescence exhibits the concentration quenching effect

which might be due to energyt ransfer resulted from higher concentrations and the cross relaxation process among mate levels pairs

for example

4

G

5/2

6

F

9/2

and

6

F

9/2

6

H

5/2

energy levels.So the suitable concentration of Sm

3+

luminescence in the Na

3

La

2

(BO

3

)

3

host was about 6mol%.