Selective synthesis and advanced characteristic of CdSe semiconductor quantum dots by aqueous phase

Abstract

This work mainly investigated the influences of some factors, such as, synthesis methods, precursor alternatives, and vacuum heat-treating process, etc, on the fluorescent characteristics of the semiconductor quantum dots synthesized by aqueous phase. The research results indicate that the fluorescent characteristic of water-solution sample prepared from Na₂ S0₃ precursor was sensitive to water bath heating time, and specially, its photoluminescence spectrum shows the unique phenomenon of double excitation and emission peaks. Meanwhile, the fluorescent characteristic of water-solution sample prepared from NaBH₄ precursor is slightly influenced by water bath heating time, and the surface of CdSe quantum dots could be passivated by the excessive amount of NaBH₄ precursor, which results in the effective decrease of surface traps and great enhancement of quantum yield. Furthermore, the fluorescent emission peaks of samples could be sharpened by vacuum heat-treating process, with its spectral full width at half of maximum (FWHM) around 30–40 nm, so the emission peaks become redshifi, of which the intensity greatly increases.