ZnS nanoparticles doped with Cu(I ) by controlling coordination and precipitation in aqueous solution
A novel method for the synthesis of ZnS5Cu colloids has were used as both ligand and surfactant, and acted to stabilize
been studied in aqueous solution, in which the Cu+ ions Cu+ ions in aqueous solution and minimize the solubility
were incorporated into the ZnS matrix by the assistance diVerence between Cu2S and ZnS. By the use of these sulfur
of a sulfur-containing ligand, i.e. thiourea or thiosulfate. containing ligands, nanosized ZnS5Cu particles were obtained
The optical properties of the colloids (absorption, emission and their optical properties (absorption, excitation, and emisand
excitation spectra) were studied. Compared with the sion spectra) were studied.
bulk materials, the absorption band-edge is blue-shifted, ZnS colloid was prepared as described previously,5,6 with
which is attributed to a quantum size effect. The average only minor modifications. Freshly prepared ZnCl2 and ligand
ZnS nanoparticle size, deduced from the absorption spec- solutions (thiourea or sodium thiosulfate) were stoichiotra
by an effective mass approximation, is about 4 nm.
metrically mixed together. Under continuous stirring, freshly Upon excitation at 325 nm, a broad green emission band
prepared sodium sulfide solution was added to the above is observed, while for samples doped with 0.2% Cu, a blue
mixture. The addition rate was controlled at 1.0 ml min−1 by emissi无忧论文 【http://www.uklunwen.com】on band at 450 nm is also observed, which is
quenched at higher dopant concentrations. |
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