Rare earth tantalate is a kind of outstanding host material. Since containing elements with high atomic number

owing high density

strong X-ray absorption

high chemical stability and good radiation persistence

yttrium orthotantalate (YTaO

4

) was considered as a promising host for both X-ray and VUV phosphors.YTaO

4

: Gd

Eu was synthesized by solid state reaction

and the conditions of reaction were studied in detail: The mixture of appropriate amounts of Y

2

O

3

(99.99%)

Eu

2

O

3

(99.99%)

Gd

2

O

3

(99.99%)

Ta

2

O

5

(99.999%) and Li

2

SO

4

(A.R)

the Li

2

SO

4

was added 1% as flux

was thoroughly ground and then move to an aluminate crucible. The furnace was heated to and kept at 1 250 ℃. The crucible was put into the furnace and fired for 4 h. The crucible was taken out directly from furnace at 1 250 ℃. After reground

the mixture was heated again at 1 250 ℃ for another 4 h. The crucible was then taken out from the furnace at 1 250 ℃. The sample of pure M'-YTaO

4

was obtained when the crucible was cooled to room temperature. The XRD result indicated that we got the pure M' type of YTaO

4

: Gd

Eu.The excitation and emissioin spectra of YTaO

4

were measured. The excitation band at 230 nm is described to a charge transfer band nature of TaO

3-

4

group. The emission band of YTaO

4

situated at 365 nm. The main emission peak of YTaO

4

: Eu

3+

is at 611 nm and the excitation band of YTaO

4

: Eu

3+

is at about 250 nm. The excitation band at 250 nm was attributed to the result of the overlap of two charge transfer bands within Eu-O and Ta-O. This overlap makes the UV absorption of the phosphor enhanced. The quenching concentration of Y

1-x

Eu

x

TaO

4

luminescence is at about x=0.06.For the spectra of Y

0.94-y

Gd

y

Eu

0.06

TaO

4

the doping of Gd

3+

ion into YTaO

4

: Eu

3+

did not change the energy position of Eu

3+

luminescence

but enhanced the emission intensity of phosphors. The best doping concentration of y is about 0.1.For the emission spectra of Y

0.94

Eu

0.06

TaO

4

and Y

0.84

Gd

0.10

Eu

0.06

TaO

4

under VUV excitation

the main emission peaks of the two phosphors are the same at 612 nm. The chromaticity coordinates are x=0.652

y=0.348. The luminescent properties of the samples were studied on the VUV excitation spectra and emission spectra. It was concluded that Y

0.84

Gd

0.10

Eu

0.06

TaO

4

gets good luminescent effect

and the energy transfer between TaO

3-

4

and Eu

3+

Eu

3+

and Gd

3+

occurs.