An experimental and theoretical mechanistic study of biexciton quantum yield enhancement in single quantum dots near gold nanoparticles

    Authors

    S. Dey; Y. D. Zhou; X. D. Tian; J. A. Jenkins; O. Chen; S. L. Zou;J. Zhao

    Comments

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    Abbreviated Journal Title

    Nanoscale

    Keywords

    EXCITON-PLASMON INTERACTIONS; CORE-SHELL NANOCRYSTALS; SEMICONDUCTOR; NANOCRYSTALS; RAMAN-SCATTERING; OPTICAL GAIN; FLUORESCENCE; EMISSION; PHOTOLUMINESCENCE; BLINKING; SURFACE; Chemistry, Multidisciplinary; Nanoscience & Nanotechnology; Materials; Science, Multidisciplinary; Physics, Applied

    Abstract

    In this work, we systematically investigated the plasmonic effect on blinking, photon antibunching behavior and biexciton emission of single CdSe/CdS core/shell quantum dots (QDs) near gold nanoparticles (NPs) with a silica shell (Au@SiO2). In order to obtain a strong interaction between the plasmons and excitons, the Au@SiO2 NPs and CdSe/CdS QDs of appropriate sizes were chosen so that the plasmon resonance overlaps with the absorption and emission of the QDs. We observed that in the regime of a low excitation power, the photon antibunching and blinking properties of single QDs were modified significantly when the QDs were on the Au@SiO2 substrates compared to those on glass. Most significantly, second-order photon intensity correlation data show that the presence of plasmons increases the ratio of the biexciton quantum yield over the exciton quantum yield (QY(BX)/Q(YX)). An electrodynamics model was developed to quantify the effect of plasmons on the lifetime, quantum yield, and emission intensity of the biexcitons for the QDs. Good agreement was obtained between the experimentally measured and calculated changes in QY(BX)/Q(YX) due to Au@SiO2 NPs, showing the validity of the developed model. The theoretical studies also indicated that the relative position of the QDs to the Au NPs and the orientation of the electric field are important factors that regulate the emission properties of the excitons and biexcitons of QDs. The study suggests that the multiexciton emission efficiency in QD systems can be manipulated by employing properly designed plasmonic structures.

    Journal Title

    Nanoscale

    Volume

    7

    Issue/Number

    15

    Publication Date

    1-1-2015

    Document Type

    Article

    Language

    English

    First Page

    6851

    Last Page

    6858

    WOS Identifier

    WOS:000352277500055

    ISSN

    2040-3364

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