A red Y

2

O

2

S:Eu

3+

Mg

2+

Ti

4+

phosphor is synthesized by co-precipitation method using the metal oxide

nitric acid and oxalic acid.Nitric acid is used as a solvent to dissolve the raw materials and then form the nitrate solution

while the oxalic acid is used to form precipitation.Since all of the raw materials are mixed at the molecular level in solution

a highly uniform product is achieved.The morphology and crystal structure of synthesized phosphors is investigated by the SEM patterns and the XRD patterns.The SEM patterns analysis showed that the phosphors prepared by co-precipitation method have very relaxing structure with the particle size of about 5.0 m.This is due to the realization of the material mixture in molecule scales during the doping process of co-precipitation method.The X-ray diffraction analysis showed that XRD pattern of the sample is coincident with the JCPDS Card(No.24-1424) and the sample has crystal structure of Y

2

O

2

S

which belongs to hexagonal and the crystal lattice constant is as follows:

a

0

=0.3784 nm

c

0

=0.6589 nm.It indicated that the crystal structure hasnt change with the doping of Eu

3+

Mg

2+

and Ti

4+

.The emission intensity of the samples with various concentration of Eu

3+

prepared by the co-precipitation and solid-state method

are compared with each other.When concentration quenching of Eu

3+

appears

the peak of radioactive spectrum rooting in high excited state of Eu

3+

vanishes.So we can analyze qualitatively about the amount of Eu

3+

admitted to enter the crystal lattice through comparing the change of

I

587.6

/

I

627.0

when

I

is defined as the intensity of emission peak located at wavelength .The result shows that

I

587.6

/

I

627.0

of the phosphor prepared by solid-state method obviously decreases with the increasing of concentration of Eu

3+

while it is steady with co-precipitation method.So the co-precipitation synthesis method can make the Eu

3+

enter into Y

2

O

2

S host more easily and form more effective luminescent centers than that synthesed by solid-state method.