Using acrylamide (CH

2

=CHCONH

2

) to form long chains of polyacrylamide and a cross-linker N

N-methylenebisacrylamide (CH

2

=CHCONHCH

2

NHCOCH=CH

2

) to achieve tangled network

hydro-gen peroxide (H

2

O

2

) as initiator and N

N

N

N-tetramethylethylenediamide [(CH

3

)

2

NCH

2

CH

2

N(CH

3

)

2

] as activator

we have successfully prepared the precursor from nitrates (aluminum nitrate

yttrium nitrate

and terbium nitrate)

the precursor was subsequently heat-treated from 700℃ to 1 400℃ for 4 h to form terbium-doped yttrium aluminum garnet (YAG:Tb

3+

) phosphor powders.The synthesized powders were characterized by thermogravimertry-differential thermal analysis (TG-DTA)

X-ray diffraction (XRD)

scanning electron microscopy (SEM) and fluorescence spectrometer.XRD analysis demonstrated that phase-pure YAG was ob-tained directly from the precursor at 850℃

without the formation of any intermediate phase (s) of YAP (YAlO

3

) and/or YAM (YAl

4

O

9

).SEM images showed the particles were uniform

and the grain size in-creased with a rise in heat-treating temperature.The excitation spectrum consisted of three peaks with the highest intensity at 272 nm

the second at 230 nm and the third at 324 nm

respectively

all corresponding to the Th

3+

4f-5d absorption.

5

D

4

-

7

F

j

(

j

=6

5

4

3) emissions were also observed clearly

the highest emission peaked is at 541.8 nm for the

5

D

4

-

7

F

5

transition of Th

3+

the second is for the

5

D

4

-

7

F

6

with two lines at 486 nm and 490 nm

and the weaker emission from about 570 nm to 630 nm was corresponding to the transi-tions of

5

D

4

-

7

F

4

and

5

D

4

-

7

F

3

.Enhanced luminescence intensity could be obtained by rising the sintering tem-perature which may improve the crystallization of YAG particles and favor the doping of Tb

3+

ions into YAG lattices.Concentration quenching phenomenon appeared when Tb

3+

molefraction (value of x) in (Y

1-x

Tb

x

)

3

Al

5

O

12

is over 0.06.