Effects of Dy

3+

ions on red long afterglow of Mg

2

SiO

4

:Dy

3+

Mn

2+

are investigated

which will help to discover the long lasting phosphorescent mechanism of this material.Red long afterglow phosphor

Mg

2

SiO

4

doped with Dy

3+

and Mn

2+

was prepared by solid-state reaction(SS)at 1300℃.The samples show a red(emission)peaked at 660 nm under UV excitation

which can be assigned as

4

T

1

(

4

G)

6

A

1

(

6

S)transition of Mn

2+

.The excitation and emission spectra of single-doped series were measured

and the energy levels of Mn

2+

and Dy

3+

in Mg

2

SiO

4

were also assigned.In the excitation spectra of Mn

2+

650 nm emission of Mg

2

SiO

4

there are several intense bands in the visible region corresponding to the transitions of

6

A

1

(

6

S)

4

T

1

(

4

G)(542 nm)

6

A

1

(

6

S)

4

T

2

(

4

G)(459 nm

429 nm)

6

A

1

(

6

S)

4

E(

4

G)/

4

A

1

(

4

G)(413 nm).It is a main advantage of this material.In the co-doped series

energy transfer from Dy

3+

to Mn

2+

was analyzed.When the concentration of Dy

3+

was less than 5%

the emission intensity of Mn

2+

increased with increasing Dy

3+

concentration.After irradiated by low-pressure mercury lamp

the afterglow time of Mn

2+

doped and co-doped with Dy

3+

samples is 6 and 17 min

respectively.In the thermoluminescence curves of co-doped series

Dy

3+

induced a new thermoluminescence peak at 70℃

showing its effect for extending the afterglow of Mn

2+

luminescence.