PHOTOLUMINESCENCE OF CDSE/ZNS QUANTUM DOTS ENHANCED BY SILVER COLLOIDS

PHOTOLUMINESCENCE OF CDSE/ZNS QUANTUM DOTS ENHANCED BY SILVER COLLOIDS

In this study, we fabricated CdSe/ZnS-SiO2-Ag colloid three-layer hybrid films by the layer-by-layer coating. The CdSe/ZnSlayer and the Ag-nanoparticle layer were separated by a SiO2 layer fabricated from tetraethyl orthosilicate. The localized surfacePlasmon resonance wavelength of Ag colloids has a red shift after the SiO2 layer is covered on the Ag colloids. Experimental resultsshowed that the optimal photoluminescence (PL) enhancement occured at an appropriate distance and could reach to 3.1-foldcompared to the PL of pristine quantum dots (QD)s. The result may arise from the fact that the enhanced electromagnetic fieldcaused from localized surface plasmon resonance is weakened with distance between CdSe/ZnS QDs and Ag colloids much moreslowly than the nonradiative energy transfer.