A Ce3+ sensitized, Tb3+, Mn2+ codoped polyaluminate phosphor

A Ce3+ sensitized, Tb3+, Mn2+ codoped polyaluminate phosphor

Journal of Luminescence 40&41 (1988) 661—662 North-Holland, Amsterdam 661 3~SENSITIZED, Tb3~, Mn2~COIJOPED POLYALUMINATE PHOSPHOR A Ce Guangyan HO...

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Journal of Luminescence 40&41 (1988) 661—662 North-Holland, Amsterdam

661

3~SENSITIZED, Tb3~, Mn2~COIJOPED POLYALUMINATE PHOSPHOR

A Ce

Guangyan HONG, Qienxin JIA and Younj LI Changchun Institute

of Applied Chemistry, Academia Sinica,

Changchun, China

The idea of using oI~e± sensitizer with two “cooperative” activator has been carrierd out in a Ce3+ sensitized, Tb , Mn codoped polyaluminate. The phosphor emits strong green light and may be used as a competitive component of tricolor phosphor for fluorescent lamp. For improving the light output of a phosphor, people have made many efforts hosts,

to

effective

make the

best

sensitization,

in developing new

use of doping

Ex

or by

Em

uaually in the sensiti-

zation case one activator is used with one sensitizer. On the bases of the work on the luminescence

of Ce_Tb[1_3},

considering energy

that

due

transfer,

a

to

Ce—Mn~41 systems,

and

the inefficient

S——S

fairly

high

200

300

300

400

500

concentration

nm

of the activator is needed for example in some Ce—Tb

couple,

here,

we

proposed an alternate

means i.e. to use one sensitizer with two “co— operative” activators; one of them emits in a broad band with peak near the region of sensi— -

tive

In concrete, this 3~ idea has been carried out in a Ce sensitized, 3+ 2+ Tb , Mn codoped polyaluminate. The phosphor

FIGURE 1 3+ Spectra of Ce The excitation

spectra

of Tb

at

228,

3+

consists

of

respond of human eye.

-

thus prepared -

emits strong

-

green light under

-

-

-

UV excitation and may be used as a competitive component of tricolor phosphor for fluorescent

many peaks.

i.e.

218,

253,

273,

283,

302, 319, 340, emission peaks

350, 368, 379 and 485nm. The situate at 490, 541, 585 and 5 7 625nm, corresponding to the B —— F. transition 4 j ig. )~

lamp. Ce3+ sensitized Tb3-i- , Mn 2+ codoped poly— aluminates were prepared by a solid state reac-

tion.

Ex

Em

A1

2O3, MgO, CeO2, Tb407, MnCO3 in the calculated amount and a certain amount of flux were mixed and fired at 1300°C for 2 hrs

in

j1~~

a reducing atmosphere. The structure

of the products

was

check by

x—ray diffraction to be hexagonal. In this peak locates at host 28mm,theandexcitation the emission

3+ of peakCe at -

348nm. Both of them are broad bands (Fig. 1). 0022—2313/88/503.50 © Elsevier Science Publishers By. (North-Holland Physics Publishing Division)

200

300

400

500

__________________

500

600 nm

FIGURE 2 3+ Spectra of Tb

G. Hong et a!.

662

codoped / Ce3~sensitized, Th3~,Mn2~

polyaluminate phosphor

I,—”

JN~/jJIk\~Ji\~j~\ 300

400

500

500

520 nm



300

400

500

600

700 nm

FIGURE 3 Spectra of Mn2~

FIGj~E~‘ 3+ 2+ Emission spectra of Ce , Tb , Mn

The main excitation bands of Mn2+ locate at 280,

360,

385,

425,

emission band peak

449,

482

and

at 5lOnm (Fig.3),

49mm.

Its

a position

just between the 490 and 541nm peaks of TbS+. In this host the sensitization of Ce3+ may

It seems to us that above proposal, work with tive”

a sensitizer

acitivators

but with

may lead

phosphor in other systems

i.e.

to

two

“coopers—

to more

efficient

too, and furthermore

enhance the emission intensity of Tb3+ or Mn2+

it is probable to develop a phosphor which have

by

several

several

fold and

it

does not

change their

activators

and all

of them emit

peak positions. And a sample sensitized by Ce3+ codoped with Tb3+ and Mn 2+ when excited at 28mm

ciently in a given host.

(excitation

Natural Science Foundation of China.

peak

of

Ce3+)

emits

emission peaks corresponding tions of Tb

+

to 5D

the

usual

The project was supported

effi—

by National

TF. transi-

but at the same time 4— another broad

REFERENCES

band emission peaking at 516nm originated from 2+ Mn also appears in the spectra; i.e. the exci— 3+ tation energy of Ce can be effectively and 3+ 2+ simutaneously transfer to Tb and Mn and their emission are compounded together, so that

1. J.M.P.J. Verstegen, J. Electrochem. Soc., 121 (1974) 1623. 2. Hong Guangyan, Li Youmo, Luminescence and

the total

4. Hong Guanyan, Li Youmo, Yue Shuying, Inorga— nica Chimica Acata, 118, (1986) 81.

-

emission intensity .

-

increases (Fig.4). 2+ Mn the amount

It implies that by incorporating

of expensive Tb3+ needed may be reduced in preparing an efficient green light emitting phosphor.

-

Display Devices, Vol.5, -

-

No.2, (1984)82. -

3. Li Youmo, et al., Luminescence and Display Devices, Vol.2, No.1, (1981) 47.