Plasmon-assisted suppression of surface trap states and enhanced band-edge emission in a bare CdTe quantum dot

Year: 2019

Authors: Flatae A. M., Tantussi F., Messina G. C., De Angelis F., Agio M.

Autors Affiliation: Laboratory of Nano-Optics and Cμ, University of Siegen, 57072 Siegen, Germany; Istituto Italiano di Tecnologia, 16163 Genova, Italy; National Institute of Optics (INO-CNR), 50125 Florence, Italy

Abstract: Colloidal quantum dots have emerged as a versatile photoluminescent and optoelectronic material. Limitations like fluorescence intermittency, nonradiative Auger recombination, and surface traps are commonly addressed by growing a wide-band-gap shell. However, the shell isolates the excitonic wave function and reduces its interaction with the external environment necessary for different applications. Furthermore, their long emission lifetime hinders their use in high-speed optoelectronics. Here, we demonstrate a high degree of control on the photophysics of a bare core CdTe quantum dot solely by plasmon coupling, showing that more than 99% of the surface defect-state emission from a trap-rich quantum dot can be quenched. Moreover, the band-edge state excitonic and biexcitonic emission rates are Purcell enhanced by 1460- and 613-fold, respectively. Our findings show how plasmon coupling on bare quantum dots could make chemical approaches developed for improving their optical properties unnecessary, with implications for nanoscale lasers, light-emitting devices, solar cells, and ultrafast single- photon sources.


Volume: 10 (11)      Pages from: 2874  to: 2878

More Information: The authors gratefully acknowledge financial support from the University of Siegen, Germany, and the Italian Institute of Technology (IIT), Italy. This Letter is based upon work from COST Action MP1403 “Nanoscale Quantum Optics,” supported by COST (European Cooperation in Science and Technology). A.M.F. would like to thank F. Dinelli for advice on the AFM techniques, M. Ardini and M. Mousavi for advice on functionalization protocols, and P. Reuschel for technical assistance.
KeyWords: CDSE/CDS core/shell nanocrystals; single-molecule fluorescence; light-emitting-diodes; room-temperature; photon emission; antenna; growth; colloidal quantum dots; nanoantennas; photophysics
DOI: 10.1021/acs.jpclett.9b01083

Citations: 18
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