Elucidation of Multi-Exciton Dynamics of a Single Quantum Dot Interacted with Metal Nanostructures Using a Single Quantum Dot-Silver Nanowire System

One of the important interesting exciton dynamics is the simultaneous existence of the multiple excitons in a single quantum dot (QD). By using the multiexciton, the efficiency of the solar cells and light emission devices can be considerably increased. However, the multiexciton are annihilated by the nonradiative Auger recombination. We have revealed that the Auger recombination process can be suppressed by interacted with the metal nanostructure (MNS) [1-3]. As the mechanism, we considered that the multiexciton in a single QD induce the plasmon on a MNS before the Auger recombination, then the plasmon emits photons. In previous systems, however, it was difficult to observe the emissions from a single QD and a MNS separately. In this work, to observe the emissions separately, we used "a single QD-silver nanowire (AgNW)" system. By observing the emission behaviors of a single QD and the AgNW ends, the multiexciton dynamics interacted with the MNSs was discussed.

Figure 1 (a, b) shows AFM and fluorescence images of the system. As showed in Figure 1 (b), the scattering lights from the AgNW ends in Figure 1 (a) were observed. This indicates that the multiexciton of the QD induced the plasmon on the AgNW. And then, the plasmon propagated and emitted the photons at the ends. In this time, we succeeded in measuring the emissions from a single QD and AgNW ends separately. The photon antibunching behaviors of the single QD and the AgNW ends will be reported.

[1] S. Masuo, T. Tanaka, S. Machida, A. Itaya, J. Photochem. Photobio. A, 237, 24 (2012).

[2] H. Naiki, S. Masuo, A. Itaya, J. Phys. Chem. C, 115, 23229 (2011).

[3] S. Masuo, H. Naiki, S. Machida, A. Itaya, Appl. Phys. Lett., 95, 193106 (2009).

alb84236@kwansei.ac.jp