Optical properties of ZnS:Cu colloid prepared with sulfurous ligands
Abstract
A novel method of the synthesis of ZnS:Cu colloid was studied in an aqueous solution, in which Cu1 was successfully
inducted into ZnS host with the assistance of sulfurous ligand: thiourea or thiosulfate. The optical properties were studied by
absorption spectra, emission spectra and excitation spectra. Compared with that of the bulk materials, the absorption band-edge
demonstrates apparently blue shift, which is attributed to the quantum size effect. The average particle size of ZnS nanoparticles
is about 3–4 nm deduced from absorption spectra according to the effective mass approximation. Excited at about 320 nm, a
green emission band at 520 nm can be observed, which corresponds to Cu1 luminescent center, this result is consistent with the
postulation that Cu1 replaced the Zn21 ions in the lattice of ZnS nanocrystals. Excitation spectra also confirmed the above
postulation. Thiourea or thiosulfate plays an important role in the synthesis process, it can act as ligand and surfactant
simultaneously, and the functions can be described as doped-element-stabilizing effect, solubility-leveling effect and
surface-protecting effect. q1999 Elsevier Science Ltd. All rights reserved.
Keywords: A. Nanostructures; A. Semiconductors; D. Optical properties; E. Luminescence无忧论文 【http://www.uklunwen.com】 |
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