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Publications (2)0.92 Total impact

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    ABSTRACT: Four sizes of water-soluble thiol-capped CdTe quantum dots (QDs) have been synthesized and used to investigate the photoluminescence (PL) responses to Ag+ ions. For small particles, the CdTe QDs exhibit PL enhancement in the presence of lower concentration of Ag+ but show obvious quenching with the further increase of Ag+; for larger particles, however, PL of CdTe QDs is quenched all the time with the Ag+ addition, no PL enhancement is observed. Mechanism study shows that small QDs with more traps on the particle surface are effectively passivated by initial adsorbed Ag+, which accounts for the PL enhancement observed; after the initial traps are saturated, the excess Ag+ facilitates nonradiative recombination, resulting in PL quenching. For larger particles, the nonradiative recombination dominates the whole process even for the lower concentration of Ag+, due to the fewer traps on the QD surface. Compared with larger particles, the small CdTe QDs are more suitable for sensing Ag+ because of the more sensitive and selective PL response. To our best knowledge, this is the first systematical study on the interaction of Ag+ with different-sized CdTe QDs.
    Journal of Luminescence - J LUMINESC. 01/2008; 128(1):166-172.
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    ABSTRACT: Three different size CdTe quantum dots (QDs) capped by 3-mercaptopropionic acid (MPA) have been prepared in aqueous solutions, and their interactions with Cu2+ and Hg2+ have been investigated. The opposite size-dependent fluorescence quenching of CdTe QDs by Hg2+ and Cu2+ was observed: Hg2+ quenched smaller particles more efficiently than larger ones while larger particles were more markedly quenched by Cu2+. Based on the different size responses, Hg2+ and Cu2+ were respectively detected with high sensitivity and selectivity, for the first time, using the QDs with different sizes but the same components and capping ligands.
    Chinese Journal of Chemistry 12/2007; 25(12):1836 - 1841. · 0.92 Impact Factor