Colloidal Assembly of Au–Quantum Dot–Au Sandwiched Nanostructures with Strong Plasmon–Exciton Coupling

Abstract

Strong plasmon−exciton coupling could occur in hybrid metal−dye/ semiconductor nanostructures, where the fast energy exchange between plasmons and excitons leads to two new eigenmodes of the system, known as Rabi splitting. In experiments, strongly coupled nanosystems are difficult to obtain because they require some strict conditions, such as low plasmonic damping, small plasmon mode volume, and good spectral overlap. This work demonstrates strongly coupled metal− semiconductor nanostructures can be constructed using colloidal assembly. Specifically, sandwiched Au−quantum dot−Au nanostructures were created through the assembly of Au nanoparticles and colloidal quantum dots (QDs). The sizes of the QDs and the assembly conditions were varied to control the mode volume of the plasmonic cavity formed between the two Au nanoparticles. With a decreased gap size, Rabi splitting was observed in both dark-field scattering and fluorescence spectra of single Au−QD−Au nanostructures. Theoretical simulations revealed that the strong coupling occurred between the excitons and the octupolar plasmon modes.

Light‐Controlled Near‐Field Energy Transfer in Plasmonic Metasurface Coupled MoS2Monolayer

“…Resonance. [39] Besides plasmon-2D semiconductors , [27,28] applications in other plasmon-exciton coupling systems, such as plasmon-quantum dots [40,41] and plasmon-dye molecules systems, [42] have also been investigated.…”

“…[ 4,33,34 ] Different coupling mechanisms of plasmonic nanostructures and 2D semiconductor systems have been reported, including electromagnetic field enhancement, [ 28,35 ] hot electron doping, [ 3 ] strong coupling, [ 27,36,37 ] valleytronic modulation, [ 34,38 ] and dark‐exciton‐mediated Fano Resonance. [ 39 ] Besides plasmon‐2D semiconductors , [ 27,28 ] applications in other plasmon‐exciton coupling systems, such as plasmon‐quantum dots [ 40,41 ] and plasmon‐dye molecules systems, [ 42 ] have also been investigated.…”

Dynamic Control of Quantum Emitters Strongly Coupled to the Isolated Plasmon Cavity by the Microfluidic Device

“…Achieving a strong coupling between a single-mode field and quantum emitters helps to understand the physical mechanism of the light–matter coupling processes. Relevant research studies are essential for potential quantum optical applications such as ultrafast single-photon switches, , thresholdless nanolasers, , and molecular fingerprinting. , In the traditional solid-state environment, the cavity morphology and the coated excitonic materials are fixed once the nanoparticle is fabricated, making it challenging to achieve an on-demand control of the coupling state. In recent years, the all-optical control of plasmon–exciton coupling claimed much attention due to its ultrafast (even down to picoseconds) character, which is a feasible choice for photoswitching applications. − However, the realization of the optical control relies on the use of photochromic molecules, which are known to suffer from the photobleaching effect, making it challenging to achieve robust and reversible control.…”

“…Relevant research studies are essential for potential quantum optical applications such as ultrafast single-photon switches, 16,17 thresholdless nanolasers, 18,19 and molecular fingerprinting. 20,21 In the traditional solid-state environment, the cavity morphology and the coated excitonic materials are fixed once the nanoparticle is fabricated, making it challenging to achieve an on-demand control of the coupling state. In recent years, the all-optical control of plasmon−exciton coupling claimed much attention due to its ultrafast (even down to picoseconds) character, which is a feasible choice for photoswitching applications.…”

Quantum Dot Photocatalysts for Organic Transformations

“…Because of the outstanding properties, scientists have been investigating the photocatalytic performance of QDs over decades, benefitting from the continuous achievements in the synthesis of such materials. − Studies on the utilization of QD photocatalysts for organic conversions have been more frequently reported in recent years, which provides new and effective synthetic routes to high value-added molecules and novel solutions to organic pollutant treatments under mild conditions. − In this Perspective, we summarize recent advances of QD-photocatalyzed organic reactions categorized into net reductive reactions, net oxidative reactions, and redox neutral reactions. We also provide useful information to enrich the field in terms of nanostructure designs for charge separation, ligand shell engineering for optimizing reaction efficiency, advanced in situ techniques to assist the exploration of underlying reaction mechanisms, and promising accelerated reaction optimization facilitated by modern computing technologies.…”