As a new generation of long afterglow phosphors

rare earth doped alkaline earth silicates and aluminates are drawing more and more attention. However

though the blue and the green phosphors with excellent afterglow performance are put into commercial use

the white afterglow phosphor suitable for illuminating is dissatisfying. Recently

a novel method of achieving stable white afterglow through combination of different coloured emissions from single activator

such as Dy

3+

or Tb

3+

was developed.Following this new method

a series of Dy

3+

-doped calcium magnesium silicate phosphors: CaMgSi

2

O

6

:Dy

3+

Ca

2

MgSi

2

O

7

:Dy

3+

and Ca

3

MgSi

2

O

8

:Dy

3+

with white long-lasting afterglow were prepared and investigated. The characteristic intra-configurational 4f emissions of Dy

3+

were observed in the emission spectra as well as the afterglow spectra under ultraviolet excitation. The combination of the 480 nm blue emission corresponding to the

4

F

9/2

6

H

15/2

transition and the 575 nm yellow emission corresponding to the

4

F

9/2

6

H

13/2

transition yielded white-light emission. The white-coloured afterglow emission can last more than 1 hour for the most of the samples under study. The concentration dependence of the ratio of the yellow emission intensity to blue emission intensity was also examined and found to be varied for the different host. The thermoluminescence spectra above room temperature are employed for the discussion of the origin of the traps and the mechanism of the persistent luminescence. The calcium magnesium silicate hosts doped with Dy

3+

are promising candidates for the development of the white long afterglow materials

although the refinements of the materials and further investigation are needed.