Cuong Dang Group

Novel nonradiative energy transfer

Mutual Energy Transfer in a Binary Colloidal Quantum Well (CQW) Complex

Two distinct CQWs play the role of donor and acceptor simultaneously in a complex consisting of 3 monolayer (ML) copper-doped CQWs and 4 ML undoped CQWs.

Band-edge excitons in 3 ML CQWs effectively transfer the excitation to excitons in 4 ML CQWs, whose energy is also harvested backward by the dopants in 3 ML CQWs.

All-optical control of exciton flow

In the spontaneous emission regime, FRET naturally occurs between a donor and an acceptor.

In contrast, upon stronger excitation, the ultrafast consumption of excitons by stimulated emission effectively engineers the excitonic flow from the donors to the acceptors.

The acceptors’ stimulated emission significantly accelerates the exciton flow, while the donors’ stimulated emission almost stops this process.

The results will provide an effective all-optical route for realizing excitonic devices under room temperature operation.

Light Matter Strong Coupling

Strong Plasmon-Wannier Mott Exciton Interaction with High Aspect Ratio Colloidal Quantum Wells

High aspect ratio colloidal quantum wells (HARCQWs) are utilized as exciton sources.

Individual plasmonic silver nanocubes are utilized as resonant structures to couple with excitons

Unprecedented giant Rabi splitting energy up to 400 meV under ambient conditions, which is observed not only in scattering but also in photoluminescent spectra.

Hybrid plasmonic nano-emitters

Hybrid plasmonic nano-emitters with controlled single quantum emitter positioning on the local excitation field

The optimal overlap of antenna’s near-field and active medium whose spatial distribution is controlled via a plasmon-triggered 2-photon polymerization of a photosensitive formulation containing QDs.

The response of these hybrid nano-emitters is shown to be highly sensitive to the excitation light polarization due to polarization-sensitive nanoscale overlap between the exciting local field and the active medium distribution.

The technique is demonstrated for single QD, showing polarization-dependent switching in the single-photon regime.