Impact of Surface Enhanced Raman Spectroscopy in Catalysis.

Catalysis stands as an indispensable cornerstone of modern society, underpinning the production of over 80% of manufactured goods and driving over 90% of industrial chemical processes. As the demand for more efficient and sustainable processes grows, better catalysts are needed. Understanding the working principles of catalysts is key, and over the last 50 years, surface-enhanced Raman Spectroscopy (SERS) has become essential.

Chiral Symmetry Breaking in Colloidal Metal Nanoparticle Solutions by Circularly Polarized Light.

Shape symmetry breaking in the formation of inorganic nanostructures is of significant current interest. It was typically achieved through the growth of colloidal nanoparticles with adsorbed chiral molecules. Photochemical processes induced through asymmetric plasmon excitation by circularly polarized light in surface immobilized nanostructures also led to symmetry breaking.

Differentiating Plasmon-Enhanced Chemical Reactions on AgPd Hollow Nanoplates through Surface-Enhanced Raman Spectroscopy.

Plasmonic photocatalysis demonstrates great potential for efficiently harnessing light energy. However, the underlying mechanisms remain enigmatic due to the transient nature of the reaction processes. Typically, plasmonic photocatalysis relies on the excitation of surface plasmon resonance (SPR) in plasmonic materials, such as metal nanoparticles, leading to the generation of high-energy or "hot electrons", albeit accompanied by photothermal heating or Joule effect.

Unraveling the Chirality Transfer from Circularly Polarized Light to Single Plasmonic Nanoparticles.

Due to their broken symmetry, chiral plasmonic nanostructures have unique optical properties and numerous applications. However, there is still a lack of comprehension regarding how chirality transfer occurs between circularly polarized light (CPL) and these structures. Here, we thoroughly investigate the plasmon-assisted growth of chiral nanoparticles from achiral Au nanocubes (AuNCs) via CPL without the involvement of any chiral molecule stimulators.

Advanced Interface Engineering in Gradient Core/Shell Quantum Dots Enables Efficient Photoelectrochemical Hydrogen Evolution.

Semiconductor core/shell quantum dots (QDs) are considered promising building blocks to fabricate photoelectrochemical (PEC) cells for the direct conversion of solar energy into hydrogen (H). However, the lattice mismatch between core and shell in such QDs results in undesirable defects and severe carrier recombination, limiting photo-induced carrier separation/transfer and solar-to-fuel conversion efficiency. Here, an interface engineering approach is explored to minimize the core-shell lattice mismatch in CdS/CdSeS (x = 0.

Silver nanoparticle enhanced metal-organic matrix with interface-engineering for efficient photocatalytic hydrogen evolution.

Integrating plasmonic nanoparticles into the photoactive metal-organic matrix is highly desirable due to the plasmonic near field enhancement, complementary light absorption, and accelerated separation of photogenerated charge carriers at the junction interface. The construction of a well-defined, intimate interface is vital for efficient charge carrier separation, however, it remains a challenge in synthesis. Here we synthesize a junction bearing intimate interface, composed of plasmonic Ag nanoparticles and matrix with silver node via a facile one-step approach.

Synergistic Combination of Charge Carriers and Energy-Transfer Processes in Plasmonic Photocatalysis.

Important efforts are currently under way in order to develop further the nascent field of plasmonic photocatalysis, striving for improved efficiencies and selectivities. A significant fraction of such efforts has been focused on distinguishing, understanding, and enhancing specific energy-transfer mechanisms from plasmonic nanostructures to their environment. Herein, we report a synthetic strategy that combines two of the main physical mechanisms driving plasmonic photocatalysis into an engineered system by rationally combining the photochemical features of energetic charge carriers and the electromagnetic field enhancement inherent to the plasmonic excitation.

Local Growth Mediated by Plasmonic Hot Carriers: Chirality from Achiral Nanocrystals Using Circularly Polarized Light.

Plasmonic nanocrystals and their assemblies are excellent tools to create functional systems, including systems with strong chiral optical responses. Here we study the possibility of growing chiral plasmonic nanocrystals from strictly nonchiral seeds of different types by using circularly polarized light as the chirality-inducing mechanism. We present a novel theoretical methodology that simulates realistic nonlinear and inhomogeneous photogrowth processes in plasmonic nanocrystals, mediated by the excitation of hot carriers that can drive surface chemistry.

Rational synthesis of novel "giant" CuInTeSe/CdS core/shell quantum dots for optoelectronics.

"Giant" core/shell quantum dots (g-QDs) are promising candidates for emerging optoelectronic technologies thanks to their facile structure/composition-tunable optoelectronic properties and outstanding photo-physical/chemical stability. Here, we synthesized a new type of CuInTeSe (CITS)/CdS g-QDs and regulated their optoelectronic properties by controlling the shell thickness. Through increasing the shell thickness, as-prepared g-QDs exhibited tunable red-shifted emission (from 900 to 1200 nm) and prolonged photoluminescence (PL) lifetimes (up to ∼14.

Chiral Photomelting of DNA-Nanocrystal Assemblies Utilizing Plasmonic Photoheating.

Chiral plasmonic nanostructures exhibit anomalously strong chiroptical signals and offer the possibility to realize asymmetric photophysical and photochemical processes controlled by circularly polarized light. Here, we use a chiral DNA-assembled nanorod pair as a model system for chiral plasmonic photomelting. We show that both the enantiomeric excess and consequent circular dichroism can be controlled with chiral light.

Distance Dependence of Förster Resonance Energy Transfer Rates in 2D Perovskite Quantum Wells via Control of Organic Spacer Length.

Two-dimensional (2D) semiconductors are attractive candidates for a variety of optoelectronic applications owing to the unique electronic properties that arise from quantum confinement along a single dimension. Incorporating nonradiative mechanisms that enable directed migration of bound charge carriers, such as Förster resonance energy transfer (FRET), could boost device efficiencies provided that FRET rates outpace undesired relaxation pathways. However, predictive models for FRET between distinct 2D states are lacking, particularly with respect to the distance between a donor and acceptor.

Challenges in Plasmonic Catalysis.

The use of nanoplasmonics to control light and heat close to the thermodynamic limit enables exciting opportunities in the field of plasmonic catalysis. The decay of plasmonic excitations creates highly nonequilibrium distributions of hot carriers that can initiate or catalyze reactions through both thermal and nonthermal pathways. In this Perspective, we present the current understanding in the field of plasmonic catalysis, capturing vibrant debates in the literature, and discuss future avenues of exploration to overcome critical bottlenecks.

Synergistic Effect of Plasmonic Gold Nanoparticles Decorated Carbon Nanotubes in Quantum Dots/TiO for Optoelectronic Devices.

Here, a facile approach to enhance the performance of solar-driven photoelectrochemical (PEC) water splitting is described by means of the synergistic effects of a hybrid network of plasmonic Au nanoparticles (NPs) decorated on multiwalled carbon nanotubes (CNTs). The device based on TiO-Au:CNTs hybrid network sensitized with colloidal CdSe/(CdSe S )/(CdS) core/alloyed shell quantum dots (QDs) yields a saturated photocurrent density of 16.10 ± 0.

Manipulating the Optoelectronic Properties of Quasi-type II CuInS/CdS Core/Shell Quantum Dots for Photoelectrochemical Cell Applications.

Colloidal core/shell heterostructured quantum dots (QDs) possessing quasi-type II band structure have demonstrated effective surface passivation and prolonged exciton lifetime, leading to enhanced charge separation/transfer efficiencies that are promising for photovoltaic device applications. Herein, we synthesized CuInS (CIS)/CdS core/shell heterostructured QDs and manipulated the optoelectronic properties via controlling the CdS shell thickness. The shell-thickness-dependent optical properties indicate the existence of a quasi-type II band structure in such core/shell QDs, which was verified by ultrafast spectroscopy and theoretical simulations.

Chiral Assembly of Gold-Silver Core-Shell Plasmonic Nanorods on DNA Origami with Strong Optical Activity.

The spatial organization of metal nanoparticles has become an important tool for manipulating light in nanophotonic applications. Silver nanoparticles, particularly silver nanorods, have excellent plasmonic properties but are prone to oxidation and are therefore inherently unstable in aqueous solutions and salt-containing buffers. Consequently, gold nanoparticles have often been favored, despite their inferior optical performance.

Terahertz three-dimensional monitoring of nanoparticle-assisted laser tissue soldering.

In view of minimally-invasive clinical interventions, laser tissue soldering assisted by plasmonic nanoparticles is emerging as an appealing concept in surgical medicine, holding the promise of surgeries without sutures. Rigorous monitoring of the plasmonically-heated solder and the underlying tissue is crucial for optimizing the soldering bonding strength and minimizing the photothermal damage. To this end, we propose a non-invasive, non-contact, and non-ionizing modality for monitoring nanoparticle-assisted laser-tissue interaction and visualizing the localized photothermal damage, by taking advantage of the unique sensitivity of terahertz radiation to the hydration level of biological tissue.

Hot Electrons Generated in Chiral Plasmonic Nanocrystals as a Mechanism for Surface Photochemistry and Chiral Growth.

The realization of chiral photochemical reactions at the molecular level has proven to be a challenging task, with invariably low efficiencies originating from very small optical circular dichroism signals. On the contrary, colloidal nanocrystals offer a very large differential response to circularly polarized light when designed with chiral geometries. We propose taking advantage of this capability, introducing a novel mechanism driving surface photochemistry in a chiral nanocrystal.

Plasmonic Copper Sulfide Nanoparticles Enable Dark Contrast in Optical Coherence Tomography.

Optical coherence tomography (OCT) is an imaging technique affording noninvasive optical biopsies. Like for other imaging techniques, the use of dedicated contrast agents helps better discerning biological features of interest during the clinical practice. Although bright OCT contrast agents have been developed, no dark counterpart has been proposed yet.

Applications of Plasmon-Enhanced Nanocatalysis to Organic Transformations.

Localized surface plasmon resonance (LSPR) is a physical phenomenon exhibited by nanoparticles of metals including coinage metals, alkali metals, aluminum, and some semiconductors which translates into electromagnetic, thermal, and chemical properties. In the past decade, LSPR has been taken advantage of in the context of catalysis. While plasmonic nanoparticles (PNPs) have been successfully applied toward enhancing catalysis of inorganic reactions such as water splitting, they have also demonstrated exciting performance in the catalysis of organic transformations with potential applications in synthesis of molecules from commodity to pharmaceutical compounds.

Hybrid Plasmonic-Aerogel Materials as Optical Superheaters with Engineered Resonances.

Solar radiation is a versatile source of energy, convertible to different forms of power. A direct path to exploit it is the generation of heat, for applications including passive building heating, but it can also drive secondary energy-conversion steps. We present a novel concept for a hybrid material which is both strongly photo-absorbing and with superior characteristics for the insulation of heat.

Optical resonances of hollow nanocubes controlled with sub-particle structural morphologies.

The structural details of nanoparticles at the sub-particle level are critical for our understanding of their functionalities and the basic mechanisms involved in their formation. In particular, the geometries of such features determine the particle's overall optical response. Hollow metallic nanoparticles (hollow-MNPs) that have cubic geometries, with varying morphologies on their walls and voids in their body, offer a platform to study the effects of such structural features on the properties of single nanoparticles and their ensemble.