Since the green long persistent phosphor SrAlO

4

:Eu

2+

Dy

3+

was reported in 1996

scientists(focused) their attention on rare earth doped aluminate

silicate or sulfide system.However

transition metal(ions)

e.g.

Mn

2+

which shows efficient luminescence and highly-saturated color in many compounds

can act as efficient emission center for luminescent materials.Zinc orthophosphate has three crystalline modifications

labled as

and crystal phases.The red long-lasting phosphorescent properties of -Zn

3

(PO

4

)

2

: Mn

2+

0.05

M

3+

(M=Al

Ga) have been reported by J.Wang

however

the phosphorescent properties of -Zn

3

(PO

4

)

2

: Mn

2+

0.05

Ga

3+

were not reported up to now. The preparation of -Zn

3

(PO

4

)

2

: Mn

2+

0.05

Ga

3+

have two processes: firstly

the stoichiometric amounts of raw materials were thoroughly mixed and ground in an agate mortar.Then the mixtures were pre-fired at 500℃ for 3 h;secondly

the pre-fired samples were thoroughly reground again

then sintered at 850℃ for three hours under a thermal-carbon reducing atmosphere by solid-state reaction.The XRD spectra show that

when the concentration of Mn

2+

＞0.3%

quenching is contributed to the formation of phase

but anneal is propitious to the formation of phase. The excitation and emission spectra show that

The three forms are excited at 234 nm()

and 246 nm( and )

with emission peaks at 507 nm for form

sharp peaks at both 507 nm and 616 nm for

and sharp peak at 507 nm and weak peak at 616 nm for form.Both the two typical peaks are attributed to the(

4

T

1

)

6

A

1

transition of Mn

2+

.The emission color mostly depends on the coordination number(CN).The Mn

2+

ion emits green light when is tetrahedrally coordinated(CN=4) in the lattice whereas it emits red light in(octahedral) coordination(CN=6). According to the long-lasting phosphorescence and decay measurement results

there is no long-lasting phosphorescent phenomenon in the form

because there is no octahedrally coordinated Mn

2+

in this structure.For the and -ZPMG

the long-lasting phosphorescent emission band is also derived from the

4

T

1g

(

4

G)

6

A

1g

(

6

S) transition of Mn

2+

in the host.The decay curves of and(-ZPMG) can be divided into two processes: a fast and a slow one.After irradiated by UV lamp(254 nm) for 5min

the red phosphorescence of the Mn

2+

Ga

3+

co-doped -ZPMG and -ZPMG are still observed in the dark for not less than 30 min and 15 min

respectively.