Manganese doped zinc sulfide aqueous colloids were synthesized.The size of the particles is seriously affected by the pH of the solution

the concentration of S

2-

etc.Suspension and its color change (from white to brown) can be observed when the pH

>

7

furthermore

the color will be deeper with the increasing of pH.The characteristic emission band of Mn

2+

can be observed and its intensity is affected by the synthesis conditions.The maximum luminescence intensity reached at

C

Mn

2+

/

C

Zn

2+

=0.04.The acidity of solution also has effect on the luminescence intensity

and the maximum luminescence intensity were located at pH=4.0 and pH=10.0.After aging the samples for 100 hours

the intensity of the sample prepared at pH=10.0 is twice of that of pH=4.0.Excess S

2-

will quench the emission.