As an important Ⅱ-Ⅵ group material

ZnS nanoparticles have attracted more interest in its novel photoelectric properties

such as its wide bandgap and high luminescent efficiency. And in the last years scholars have composed all kinds of light-emitting ZnS based nano-phosphor powder. Recently the white-light emitting EL devices are mainly made by two methods. One type of device is structured by red-light

green-light and blue-light emitting diodes. The other type is achieved by transforming two or three kinds of colors coming from different fluorescent powders. But there lacks a type of ZnS based nano-phosphor powder which emitting white-light all by itself. The white-light emitting ZnS based nanoparticles have been prepared by doping the Mn

2+

directly into the ZnS nanoparticles

which suggests a simple and easy operation. In the operation we mainly controlled two factors. One is the reactive temperature

and the other is the doping ration of the Mn

2+

in the ZnS nanoparticles. The prepared particles are as small as 7nm in diameter with consistent crystal structure and mono-dispersivity and capped or modified by methacrylic polymer. The photoluminescence (PL) spectra of the ZnS:Mn nanopowder exhibit two emission peaks under excitation of 380nm

one is at 480nm with an blue-light emitting coming from the ZnS base and the other is at 590nm with a yellow-light emitting coming from the Mn

2+

dopant. In general

the two violent emitting come into being an white-light emitting. It is worthy to give a careful discussion about the doping ration of the Mn

2+

in the ZnS nanoparticles because only the optimum dose can make the ZnS:Mn nanopowder to exhibit white-light emitting. X-ray diffraction (XRD) demonstrated that the ZnS:Mn nanoparticles have zinc blend crystal structure and Scherrer formulation was applied to estimate the diameter of the ZnS:Mn nanoparticles

which is about 7~8nm. In its UV-vis spectra

there is a blue shift of the absorption peak due to the modified surface and small size effect of the ZnS:Mn nanoparticles. According to the blue shift

Brus formulation was applied to estimate the diameter of the nanoparticles

which is consistent with the result obtained from the Scherrer formulation. The IR patterns of the ZnS:Mn nanoparticles and the one of the methacrylic acid have much comparability indicating that methacrylic polymer has capped or modified the ZnS:Mn nanoparticles.