As a new generation of long afterglow phosphors

rare earth doped 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 red afterglow phosphor doped with Dy

3+

or Tb

3+

suitable for illuminating is still dissatisfied with the white afterglow phosphor. We developed a new way to meet the conditions of red afterglow phosphor: aluminates doped with Mn

4+

.Following this new method

we synthesize LiAl

5

O

8

:Mn

4+

Li

5

AlO

4

:Mn

4+

LiAlO

2

:Mn

4+

and find that the former two have red long afterglow

this have not been reported before

then the luminescent properties of the two kinds of materials were studied

the reason of different intensity in different hosts was pointed out. We also test the intensity-concentration curve

notate that the radiation of Mn

4+

is due to transition of

2

E→

4

A

2

its emission spectrum is a broad band

peaked at 675 nm. It absorb ultraviolet strongly

the excitation spectrum extends from 620 nm to 770 nm

At last we research the mechanism of long afterglow of these materials

discuss why the long afterglow properties are different between these kinds of materials.