Zinc sulfide phosphors are currently of interest for use in a wide range of application including CRT and FED applications. In the engineering of phosphors for low voltage operation

the stoichiometry and composition must be studied and controlled so that the desired objectives of improved powder phosphors can be achieved. This will lead to a better understanding of the processes taking place. The Pb

2+

ion belongs to ns

2-

type impurities. When Pb

2+

was added into ZnS

its emissions are probably observed

including blue

green and red emission band. The luminescence properties of ZnS:Zn

Pb was strongly dependent on the preparation conditions. In this paper the luminescence of ZnS:Zn

Pb was studied. The influence of the firing temperature and the Pb

2+

concentration used in the synthesis on the origin of the blue luminescence was discussed. After the raw materials was fried at about 950℃ for an hour

the blue luminescence phosphors ZnS:Zn

Pb was obtained. It was shown that ZnS:Zn

Pb gives rather efficient blue emission under low excitation voltages. The brightness of ZnS:Zn

Pb is higher than that of ZnS:Ag

Cl and ZnS:Zn. To explain the origin of the blue emission

the lifetime measurements were performed. A strong decrease of the luminescent lifetime from ms to μs with increasing temperatures was typically found. In view of the similarity in the lifetime behaviour for A-band and D-band emission from Pb

2+

the lifetime experiments did not provide evidence for either A-band or D-band emission from Pb

2+

. It is possible to distinguish between defect related ZnS emission (μs) and Pb

2+

related emission bands. For Pb

2+

emission band (A-band or D-band) a long lifetime (ms) at low temperatures decreases to μs between ～50K and 150K. It is known that the red emission band was related to the A-band

so the blue emission band was probably related to the D-band. That is mean the D-band emission of Pb

2+

in ZnS close to a defect (e. g. S

2-

vacancy or O

2-

on S

2-

site).