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Herein, low-threshold green and red random lasing actions were investigated in inorganic caesium lead bromide (CsPbBr 3) and caesium lead iodide (CsPbI 3) perovskite microcrystals, which were grown using metal organic chemical vapor deposition. Sharp random lasing emission peaks were visible on the right side of the broad photoluminescence emission spectra. Interferential patterned sapphire substrates and novel metal nanoparticles were used to enhance the lasing emission intensity and reduce the lasing emission thresholds. Fast-decayed random lasing oscillation dynamics and backscattering angular distribution of light confirmed that the multi-scattering of light was important in the reduction of the threshold in thin films on patterned sapphire substrates. Plasmonic enhancement between gold or silver nanoparticles and the perovskite microcrystals contributed similarly to low threshold random lasing emission, which was verified using the simulation result from the finite difference time domain (FDTD) method. This work has a wide range of applications in sensing, speckle-free imaging, illumination, and medical diagnosis. [ABSTRACT FROM AUTHOR]

We discuss empirical regularities demonstrating the phenomenon of plasmon–exciton interaction in mixtures of Rose Bengal (RB) dye and spherical and pyramidal silver nanoparticles (Ag NPs and Ag NTs). We use the Z-scan technique to study nonlinear optical properties of the RB dye under the action of the second harmonic (532 nm) of 10 ns YAG:Nd3+ laser pulses. In the case of coincidence of the dye with Ag NTs with the light extinction peak at 550 nm located in the RB luminescence region, we observe the formation of a positive dynamic lens (γ = 4.0 · 10−13 cm2/W). It provides the threshold limit regime to 0.005 mJ that is not characteristic for the dye. The observed effect is due to a change in the dye state population, involved in the formation of a nonlinear optical response due to the metal nanoparticle action as an optical antenna under the resonance conditions of the Ag NTs extinction peak (550 nm) and the RB luminescence (570 nm). [ABSTRACT FROM AUTHOR]

Optical imaging modalities have emerged as a keystone in oncological research, capable of providing molecular and cellular information on cancer with the advantage of being minimally invasive toward healthy tissues. Photothermal therapy (PTT) has shown great potential, with the exceptional advantages of high specificity and noninvasiveness. Combining surface-enhanced Raman spectroscopy (SERS)-based optical imaging with PTT has shown tremendous potential in cancer theranostics (therapeutics + diagnosis). This comprehensive review article provides up-to-date information by exploring recent works focused mainly on the development of plasmonic nanoparticles for medical applications using SERS-guided PTT, including the fundamental principles behind SERS and the plasmon heating effect for PTT. [ABSTRACT FROM AUTHOR]

[Display omitted] • Unprecedent Raman and SERS characterization of the herbicide tebuthiuron (TBH). • Assignment of TBH adsorption geometries on Ag surface supported by DFT calculations. • AgNP surface control by modifications with hydrochloric acid and 2-mercaptoethanol. • TBH adsorption by thiadiazole ring in perpendicular or tending-to-parallel geometry. The vibrational assignment of the Raman and surface-enhanced Raman scattering (SERS) spectra of the herbicide tebuthiuron (TBH) was accomplished, which allowed unprecedented propositions for adsorption geometries on the surface of silver nanoparticles (AgNP). Ascribed SERS features allowed suggesting that the adsorption occurred through nitrogen atoms of thiadiazole group, since intense band shift assigned to ring mode was marking of the coordination with the metallic surface. AgNP were treated with different surface modifiers that leaded to substantial changes in TBH adsorption geometries. Spectral changes, as the enhancement of out-of-plane ring modes, were indicative of the presence of tilted thiadiazole geometries in relation to the silver surface. Density Functional Theory (DFT) calculations from TBH molecules, in isolation and in interaction with ten-atom cluster of silver leaded to obtain theoretical spectra that gave support to interpret experimental Raman and SERS spectra. [ABSTRACT FROM AUTHOR]

• A high-performance Q-switched vortex laser has been realized on a waveguide platform. • The pulse width (28 ns) is the shortest ever reported for Q-switched vortex laser. • The near-field distributions of nanoparticles arrays have been simulated. Vortex beam, particularly pulsed vortex laser, has expanded the potential applications in optics due to their unique wave-front phase structure and the determined photon orbital angular momentum. In this study, we present a novel approach including the integration of fused silica embedded with silver nanoparticles (Ag:SiO 2) into the Nd:YAG waveguide platform for achieving nanosecond vortex pulses. Using a spiral phase plate for in-cavity phase modulation, we successfully demonstrate a Q-switched vortex laser with a high repetition rate in the megahertz range and short pulse width in the nanosecond regime. Additionally, we conduct a comprehensive analysis of the near-field distributions of Ag nanoparticles with varying sizes and distributions using COMSOL simulation. This study exemplifies the integration of silica-based photonic elements for realizing a high-stability and cost-effective nanosecond vortex laser system. [ABSTRACT FROM AUTHOR]

A spatial-frequency thin-film filter with inclusions of nanoparticles operating in the visible range of the spectrum is investigated. The effect of nanoparticles embedded in the central and lateral layers of the frustrated total internal reflection filter on the spectral characteristics, considering the frequency dispersion, is investigated. It is shown that plasmonic effects cause the splitting of the filter bandwidth into a set of narrow-band spectral lines and the angular splitting of the incident beam into a set of output beams. It is demonstrated that due to the difference in the resonance conditions for s- and p-polarization waves, the spectral lines of transparency do not coincide, which indicates the possibility of using the filter as a polarizer.

Plasmonic nanoparticles (NPs) have attracted significant attention due to their unique optical properties and broad optoelectronic and photonic applications. We investigate modifications of emission in hybrid structures formed by 60 nm silver NPs and GaN planar nanowires (NWs). Bare GaN NWs exhibit photoluminescence (PL) spectra dominated by broad bands peaking at ∼3.44 eV and ∼3.33 eV, attributed to basal plane stacking faults. In hybrids, two new narrow PL lines appear at 3.36 and 3.31 eV, resulting in PL enhancement at these energies. While the 3.36 eV line in hybrid structures can be explained using the Fröhlich resonance approximation based on the electric dipole concept, the appearance of two features at 3.36 and 3.31 eV indicates the splitting of resonance lines. This phenomenon is explained in framework of theoretical model based on the interaction of the dipole with its charge image, taking into account the quadrupole moment of the silver sphere and the quadrupole field of the charge image. A good agreement is obtained between the calculated Fröhlich resonance frequencies and the experimental PL lines in hybrid structures.

Abstract Reactive oxygen species (ROS) regulate various physiological and pathological conditions in cells by interacting with signaling molecules and inducing oxidative stress. Therefore, sensitive monitoring of ROS levels in living cells is important to track cellular state and study the complex role of ROS in the development of various pathologies. Herein, we present an optically tunable plasmonic interface covered with graphene to monitor cellular ROS levels with superior sensitivity and cellular comfortability. As a sensing principle, we employed plasmon resonance energy transfer (PRET)-based spectral quenching dips modulated by redox-active cytochrome c for real-time monitoring. By transferring graphene layers to plasmonic nanoparticles immobilized on a glass substrate, the scattering profiles of the nanoprobes were adjusted in terms of the position, width, and intensity of the peaks to determine the optimal conditions for measuring the PRET signal. Using the optimized graphene-covered plasmonic nanoprobe, we obtained calibration curves over a wide concentration range from femtomoles to millimoles for hydrogen peroxide based on the change in the PRET signal. Before monitoring cellular ROS, we confirmed that a high density of cells adhered well to the graphene-covered plasmonic interface by observing immunofluorescence images of the cytoskeleton of the immobilized cells. Finally, we monitored the real-time ROS generated by the cells under oxidative stress conditions by directly measuring the spectral changes of the probes around the cells. We believe that the proposed graphene-covered tunable plasmonic interface has versatile applicability for investigating cellular stress and disease progression by monitoring ROS levels under various cellular conditions.

Increased use of classical drug therapy, including the administration of antibiotics and anticancer drugs, has led to multidrug resistance. Overcoming this resistance requires alternative therapies. Photodynamic therapy is used extensively to combat numerous ailments by killing cells by producing reactive chemical species (RCS). Plasmonic nanomaterials are excellent candidates for bactericidal and neoplastic agents due to their specialized optical properties and capacity to generate RCS. Plasmonic nanomaterials are in great demand for drug delivery, medical diagnostic applications, electronic semiconductors, biomolecular sensing, surface-enhanced Raman spectroscopy, enhancement of materials, and catalysis. This review focuses on plasmonic nanoparticle therapy for bacterial infections and cancers. In particular, mechanisms for RCS formation, toxicity, immunogenicity, and biodegradability of plasmonic nanomaterials are discussed. These materials may become important agents for treating bacterial infections and cancer in the near future, in combination with proper targeting agents and conjugation with biocompatible molecules. [ABSTRACT FROM AUTHOR]

Coronavirus is an ongoing global pandemic caused by severe acute respiratory syndrome coronavirus 2. Coronavirus disease 2019 known as COVID-19 is the worst pandemic since World War II. The outbreak of COVID-19 had a significant repercussion on the health, economy, politics, and environment, making coronavirus-related issues more complicated and becoming one of the most challenging pandemics of the last century with deadly outcomes and a high rate of the reproduction number. There are thousands of different types — or variants — of COVID circulating across the world. Viruses mutate all the time; it emphasizes the critical need for the designing of efficient vaccines to prevent virus infection, early and fast diagnosis, and effective antiviral and protective therapeutics. In this regard, the use of nanotechnology offers new opportunities for the development of novel strategies in terms of prevention, diagnosis, and treatment of COVID-19. This review presents an outline of the platforms developed using plasmonic nanoparticles in the detection, treatment, and prevention of SARS-CoV-2. We select the best strategies in each of these approaches. The properties of metallic plasmon NPs and their relevance in the development of novel point-of-care diagnosis approaches for COVID-19 are highlighted. Also, we discuss the current challenges and the future perspectives looking towards the clinical translation and the commercial aspects of nanotechnology and plasmonic NP-based diagnostic tools and therapy to fight COVID-19 pandemic. The article could be of significance for researchers dedicated to developing suitable plasmonic detection tools and therapy approaches for COVID-19 viruses and future pandemics. [ABSTRACT FROM AUTHOR]

Functionalization of colloidal nanoparticles with organic dyes, which absorb photons in complementary spectral ranges, brings a synergistic effect for harvesting additional light energy. Here, we show functionalization of near-infrared (NIR) plasmonic nanoparticles (NPs) of bare and amino-group functionalized mesoporous silica-coated copper sulphide (Cu2-xS@MSS and Cu2-xS@MSS-NH2) with specific tricarbocyanine NIR dye possessing sulfonate end groups. The role of specific surface chemistry in dye assembling on the surface of NPs is demonstrated, depending on the organic polar liquids or water used as a dispersant solvent. It is shown that dye binding to the NP surfaces occurs with different efficiency, but mostly in the monomer form in polar organic solvents. Conversely, the aqueous medium leads to different scenarios according to the NP surface chemistry. Predominant formation of the disordered dye monomers occurs on the bare surface of mesoporous silica shell (MSS), whereas the amino-group functionalized MSS accepts dye predominantly in the form of dimers. It is found that the dye–NP interaction overcomes the dye–dye interaction, leading to disruption of dye J-aggregates in the presence of the NPs. The different organization of the dye molecules on the surface of silica-coated copper sulphide NPs provides tuning of their specific functional properties, such as hot-band absorption and photoluminescence. [ABSTRACT FROM AUTHOR]

Inspired by several conventional ideas, the green phytosynthesis of gold nanoparticles (AuNPs) has many advantages over known chemical and physical methods of preparing AuNPs. With no need for special conditions, one can use this approach for large-scale synthesis. Here, we report the green synthesis of AuNPs with irregular shapes by the bio-reduction of tetrachloroauric acid by the extract of Juniperus communis L. The resulting AuNPs were characterized by UV-Vis spectroscopy, TEM, AFM, SAED, and EDX microanalysis. In the background of the unique morphology of AuNPs, we registered the blue-to-green photoluminescence with a broad plasmon signal that indicates the contributions of AuNPs with different sizes and shapes. The phytosynthesized AuNPs are promising candidates for the application in biomedicine and morphology-dependent surface plasmon resonance sensors. [ABSTRACT FROM AUTHOR]

We study the electronic excitation dynamics in ensembles of plasmonic gold nanorods (Au NRs), in view of the femtosecond transient absorption spectroscopy, and compare the results with the excitation dynamics of spherical Au nanoparticles (NPs). We use the obtained kinetics of the transient absorption of Au NRs and Au NPs to fit the theoretical profile of the temperature relaxation of the excitation dynamics of electron and lattice nanoparticles, as well as their environment under the excitation by laser pulses with duration of 150 fs. For gold nanorods, the electron–phonon interaction constant reads γNRs = 12 · 1016 W·m−3·K−1, and the heat loss is hNRs = 16 · 108 W·m−2·K−1. In the case of gold nanospheres, the constants are γNPs = 7· 1016 W·m−3·K−1 and hNRs = 8· 108 W·m−2·K−1, respectively. [ABSTRACT FROM AUTHOR]

Nanostructures enabling light manipulation in response to external stimuli offer unprecedented opportunities for efficient control over optomechanical systems at the nanoscale. The integration of stimuli‐responsive materials in such systems is an important milestone in the creation of miniaturized and smart nano‐ and micromechanical systems. In this article, a thermally sensitive mechanically driven platform based on pNIPAM microspheres modified with high refractive index dielectric silicon (Si) and plasmonic gold (Au) nanoparticles is presented to probe the temperature‐dependent reversible mechanical transformations through the second‐harmonic generation signal switching. The second‐harmonic generation process is investigated theoretically and experimentally depending on the applied temperature and pNIPAM phase. It is found that the change of the interparticle distance in the system during the phase transition provokes generation of optically induced static electric field probed by the second‐harmonic generation signal. The obtained results can become the foundation in the creation of nanophotonic devices based on thermo‐sensitive polymers, as they combine reversible tuning of optical signals with the opportunity of local probing of mechanical changes. [ABSTRACT FROM AUTHOR]

Thanks to spontaneous polarization in molecular structure, piezoelectric polymer, poly(vinylidene fluoride) (PVDF) holds great potential for diverse applications such as organic memory and electromechanical devices. However, the transformation of PVDF into a highly polarized β‐phase has still relied on conventional processes such as repeated mechanical strain, high‐temperature heat treatment, and high‐voltage electric poling, which are time‐consuming and can potentially cause undesired damages. Here, an ultrafast and reversible digital patterning process to transform the polymorphic phase of the PVDF has been developed using the interaction of laser with molecular structure. Plasmonic gold nanoparticles realize the interaction between PVDF and laser by increasing the absorption of the laser and amplifying its characteristics. The parameters of the laser process for phase conversion are designed under the theoretical background based on molecular dynamics (MD) simulation, and through this, the process is able to freely convert phases by simple parameter modifications. The selective laser process enables a monolithically integrated heterogeneous phase of PVDF which is not allowed in conventional single‐phase producing processes. Moreover, a practical soft robot that can control its direction has been developed by utilizing the difference in mechanical responses of each phase to the electric field in a monolithically integrated single functional layer. [ABSTRACT FROM AUTHOR]

Conventional anticancer treatments, such as radiotherapy and chemotherapy, have significantly improved cancer therapy. Nevertheless, the existing traditional anticancer treatments have been reported to cause serious side effects and resistance to cancer and even to severely affect the quality of life of cancer survivors, which indicates the utmost urgency to develop effective and safe anticancer treatments. As the primary focus of cancer nanotheranostics, nanomaterials with unique surface chemistry and shape have been investigated for integrating cancer diagnostics with treatment techniques, including guiding a prompt diagnosis, precise imaging, treatment with an effective dose, and real-time supervision of therapeutic efficacy. Several theranostic nanosystems have been explored for cancer diagnosis and treatment in the past decade. However, metal-based nanotheranostics continue to be the most common types of nonentities. Consequently, the present review covers the physical characteristics of effective metallic, functionalized, and hybrid nanotheranostic systems. The scope of coverage also includes the clinical advantages and limitations of cancer nanotheranostics. In light of these viewpoints, future research directions exploring the robustness and clinical viability of cancer nanotheranostics through various strategies to enhance the biocompatibility of theranostic nanoparticles are summarised. [ABSTRACT FROM AUTHOR]

Research on plasmonics and their applications in diverse fields has increased significantly over the last decade. The present work primarily aimed to bio‐fabricate silver and gold plasmonic nanoparticles and to study their potential as photocatalysts and as DNA binders. To achieve this, Ag and Au NPs were derived employing Peristrophe paniculata and their optical, morphological and structural properties were investigated by standard analytical techniques. The formation rate constant k was 2.58×10−2 min−1 and 3.56×10−2 min−1 for Ag and Au NPs correspondingly. FT‐IR analysis showed that the water‐soluble alkaloid, 5‐amino‐3,4‐dihydro‐2H‐pyrrole‐2‐carbonitrile was responsible for the stabilization of nanoparticles. Transmission electron microscopic studies disclosed the formation of uniform spherical AgNPs and irregularly shaped AuNPs and the diameter was 9.32 nm and 27.85 nm respectively which was again corroborated by XRD studies (16.64 nm and 36.08 nm). The interaction of ct‐DNA with Ag and Au NPs was investigated using absorption spectroscopy in the UV‐Vis range and the binding constant values were 2.2×105 M−1 and 8.1×106 M−1 respectively. The degradation of methylene blue and malachite green by AgNPs was almost 100 % and 65 % respectively in 3 h under sunlight and neutral pH (pseudo first order rate constants were 7.9×10−3 min−1 and 1.9×10−3 min−1). Moreover, the derived AgNPs exhibited mitigate activity against targeted pathogens. Thus, this green technique could be implicit for the eco‐friendly synthesis of Ag and Au NPs, and the prepared nanoparticles may be explored as photocatalysts for the degradation of cationic dyes without any added oxidants. [ABSTRACT FROM AUTHOR]

We study the influence of gold nanoantennas on the photoluminescence signal of silicon nanocrystals. Unlike bulk silicon, which only exhibits low photoluminescence at room temperature due to its indirect band gap, silicon nanocrystals have the advantage of producing strong and size-dependent photoluminescence. Here, we place gold nanoantennas on a layered system in which silicon nanocrystals are integrated. The nanoantennas are embedded in the layered system by subsequent overgrowth. We find that the photoluminescence signal can be manipulated ranging from attenuation to enhancement. Moreover, we investigate the impact of grating coupling and the number of antennas per antenna array on the amplification of the photoluminescence signal. [ABSTRACT FROM AUTHOR]

Analyzing the cell interface is of paramount importance in understanding how cells interact and communicate with other cells, but an advanced analytical platform that can process complex and networked interactions between cell surface ligands and receptors is lacking. Herein, we developed the cell-interface-deciphering lipid nanotablet (CID-LNT) for multiplexed real-time cell analysis. LNT is a nanoparticle-tethered lipid bilayer chip where freely diffusing plasmonic nanoparticles induce scattering signal changes. The CID-LNT transduces cell surface protein information into DNA data, which operate as nanoparticle logic gates. As a proof of concept, we detected and analyzed programmed death-ligand 1 (PD-L1) and associated immune signals (TNF-α, EGF, and IFN-γ). PD-L1 is an immune checkpoint that suppresses T cell activity with inflammatory biomolecules facilitating its expression. The CID-LNT can serve as a dynamic nanoparticle logic board, enabling the logic gate-based analysis of membrane proteins, and can be expanded to immunological synapse analysis, cell interface engineering, and molecular diagnostics.

Multivalency as an interaction principle is widely utilized in nature. It enables specific and strong binding by multiple weak interactions through enhanced avidity and is a core process in immune recognition and cellular signaling, which is also a current concept in drug design. Here, we use the high signals from plasmon-enhanced fluorescence of nanoparticles to extract binding kinetics and dynamics of multivalent interactions on the single-molecule level and in real time. We study mono-, bi-, and trivalent binding interactions using a DNA Holliday Junction as a model construct with programmable valency and introduce a step-binding model for binding kinetics relevant for structured macromolecules by including an experimentally extractable binding restriction term ω to quantify the effects from conformation, steric effects, and rigidity. We used this approach to explore how length and flexibility of the DNA ligands affect binding restriction and binding strength, where the overall binding strength decreased with spacer length. For trivalent systems, increasing spacer length additionally activated binding in the trivalent state, giving insight into the design of multivalent drug or targeting moieties. By systematically changing the receptor density, we explored the binding super selectivity of the multivalent HJ at the single-molecule level. We find a polynomial behavior of the trivalent binding strength that clearly shows receptor-density-dependent selective binding. Interestingly, we could exploit the rapidly decaying near fields of the plasmon that induce a strong dependence of the signal on the position of the dye to observe binding dynamics during single multivalent binding events.

Plasmonic nanoparticle-based chiral materials have attracted great interest due to their strong light-matter interaction and tunable resonance frequency. However, challenges remain in dynamically modulating the chiroptical activities while maintain strong signals. Here, chiral assemblies of gold nanospheres(AuNSs) are achieved via mechanical-induced surface buckling of elastic materials, in which linear chain assemblies of AuNSs transform into to 3D "S-liked" morphology along with the formation of unidirectional wrinkles during buckling. This asymmetrical structure leads to strong chiroptical responses, exhibiting circular dichroism (CD) response over vis-NIR range with signal as high as 2.6 degrees and a g-factor up to 0.11. Furthermore, the configuration of "S-liked" assembly is closely associated with the wrinkle shape, which can be tuned through post-stretching. This method facilitates mechanically induced dynamic and reversible modulation of CD magnitude, as well as switching of signal handedness. Taking advantages of the strong and alterable CD signal, the plasmonic chiral structures demonstrate great potential for multi-channel and dynamically switchable information encryption as a prototype. The strategy, based on manipulating the surface patterns of soft materials, opens up a new design principle for constructing chiral structure and modulating chiroptical activities in a continuously adjustable manner, advancing the development of chiral optical materials., (© 2024 Wiley‐VCH GmbH.)

In the pursuit of enhancing cancer treatment efficacy while minimizing side effects, near-infrared (NIR) photothermal therapy (PTT) has emerged as a promising approach. By using photothermally active nanomaterials, PTT enables localized hyperthermia, effectively eliminating cancer cells with minimal invasiveness and toxicity. Among these nanomaterials, gold nanostars (AuNS) stand out due to their tunable plasmon resonance and efficient light absorption. This study addresses the challenge of measuring nanoscale temperatures during AuNS-mediated PTT by employing X-ray absorption spectroscopy (XAS) within 3D tumor spheroids. It also aims to investigate the heat generated at the nanoscale and the resultant biological damage observed at a larger scale, utilizing confocal microscopy to establish connections between AuNS heat generation, tissue damage, and their impacts on cellular structure. These nanoscale and microscale thermal effects have been compared with macroscopic values obtained from infrared thermography, as part of a multiscale thermal analysis. The findings underscore the efficacy of AuNS in enhancing PTT and provide insights into the spatial distribution of thermal effects within tumor tissues. This research advances the understanding of localized hyperthermia in cancer therapy and underscores the potential of AuNS-based PTT for clinical applications., (© 2024 The Author(s). Advanced Healthcare Materials published by Wiley‐VCH GmbH.)

With recent developments in nanotechnologies, metal nanoparticles permeate a wide range of dimension scales, from light wavelength-scale domains down to a few nanometers approaching electronic scales. The electrodynamics at metal surfaces hosts a rich interplay between plasmon oscillations, retardation effects of light, and nonclassical (quantum) effects of electrons. Incorporating all these effects and modeling optical responses of nanoparticles generally rely on pure numerical methods, which are, however, disadvantageous in physical interpretations and computational speed. Herein, we establish a modal method that accurately predicts plasmon responses of metal nanoparticles, including both retardation and nonclassical corrections on an equal footing. The proposed method, based on electrostatic plasmon modes, is parameterized by a set of geometrically dependent factors, which, once computed, can be repeatedly used for same-shaped nanoparticles independent of size and material composition. The predictive accuracy of the method is examined for single nanoparticles, multi-scale plasmonic architectures—such as dimer structures with deep-nanometer gap—and geometrically deformed structures, with feature dimensions ranging from a few nanometers to hundreds of nanometers.

Nanoscale particles and structures hold promise in circular dichroism (CD) spectroscopy for overcoming the weakness of molecular CD signals. Significant effort have been made to characterize nanophotonic CD enhancement and find efficient ways to boost molecular chirality, but the best solution is yet to be found. In this paper, we present a rigorous analytic study of the nanophotonic CD enhancement of typical nanoparticles. We consider metallic and dielectric nanoparticles capped with chiral molecules and analyze the effect of multipolar nanoparticles on the molecular CD. We identify the spectral features of the molecular CD resulting from the electric and magnetic resonances of nanoparticles and suggest better ways to boost molecular chirality. We also clarify the contribution of particle scattering and absorption to the molecular CD and the dependence on particle size. Our work provides an exact analytic approach to nanophotonic CD enhancement and offers a rule for selecting the most efficient particle for sensitive molecular chirality detection.

We report on experimental observations of phenomenological self-trapping in plasmonic colloids of varying plasmon peaks in the visible/near infrared. A femtosecond (fs) oscillator is used in both pulsed (35 fs, 76 MHz) and continuous wave (cw) operation for comparison. We show that for both modes and for all examined colloids (and under typically applied external focusing conditions in self-trapping studies in colloidal media) nonlinear propagation is governed by thermal defocusing of the focused beam, which precedes the steady-state regime reached by particle diffusion, even far from the plasmon resonance (or equivalently for non-plasmonic colloids, even for low absorption coefficients). A strategy for the utilization of high repetition fs pulses to mitigate thermal lensing and promote gradient force-induced self-trapping is discussed. Notably, nonlinear thermal lensing is further accompanied by natural convection due to the horizontal configuration of the setup. Under resonant illumination, for both fs and cw cases, we observe mode break-up of the beam profile, most likely due to azimuthal modulation instability. Importantly, time-resolved observations of the break-up indicate that in the fs case, thermal convection heat transfer is reduced in magnitude and significantly decoupled in time from thermal conduction, presumably due to temperature increase confinement near the particles. We anticipate that our findings will trigger interest toward the use of high repetition fs pulses for self-channeling applications in nano-colloids.

The photoexcitation of plasmonic nanostructures with ultrashort laser pulses allows for elucidating the mechanisms underlying the ultrafast nonlinear optical response of such systems, gaining insight into the fundamental processes triggered by light absorption at the nanoscale. To date, the complex temporal and spectral features of the photoinduced response are not fully understood, especially when the photon energies are close to the interband transitions of the metallic medium. Herein, the effects of photoexcitation of plasmonic nanostructures are studied by resorting to a combinaion of broadband transient absorption spectroscopy and semiclassical nonlinear simulations of the energy relaxation processes following illumination. The proposed approach enables an in‐depth disentanglement of all the contributions to the ultrafast transient optical response of supported gold nanocrystals. From these methods, the apparent transient blue shift of the localized plasmon resonance observed in the pump–probe signals is rationalized as an interplay between different and spectrally dispersed permittivity modulations, instead of a simple negative permittivity change, as it could be concluded based on the Fröhlich condition. The results provide a comprehensive understanding of the thermo‐modulational nonlinearities of plasmonic nanostructures exhibiting resonances close to the interband transition threshold.

The controllable assembly of plasmonic nanoparticles has developed as one of the most significant approaches for surface enhanced Raman spectroscopy (SERS) applications. This study developed a simple approach to improve a large-scale ordered assembly of gold nanorods (GNRs) by controlling the droplet evaporation mode on hydrophobic substrates. The hydrophobic substrate was efficiently produced by spin coating the silicone oil onto the glass slides and annealing them. The analyte molecule rhodamine (R6G) was employed as a surface-enhanced Raman scattering probe to demonstrate the potential effects of the synthesized arrays. This hydrophobic platform enables the concentration and delivery of analyte molecules into the surface enhanced Raman spectroscopy sensitive site while suppressing the coffee ring effect generated by the smooth contraction motion of the base contact radius of the droplet without any pinning. Thus, the limit of detection (LOD) of the R6G analyte was lowered to 10−10 M and the homogenous dispersion of surface enhanced Raman spectroscopy hotspots within the self-assembly reproducible surface enhanced Raman spectroscopy signal. This new method enables a broad range of packing patterns and mechanisms by changing the host nanoparticles in the dispersion.

Visible light photocatalysis using plasmonic nanoparticles is gaining currency due to the possibility of using freely available sun light to generate high energy ‘hot’ electrons. However, effective strategies have to be developed for the generation and stabilization of hot electrons and hot holes. In this work, nanoparticles of a plasmonic metal (Au) were combined with a highly active catalyst (Pd) nanoparticles along with a conductive catalyst support (few layered graphene, FLG). Nanoparticles having very small size could be prepared with the help of swollen liquid crystals as soft templates. The templates allowed entrapment of FLG along with a metal salt and yielded the nanocomposites on exposure to hydrazine vapor. Reduction of para-nitrophenol (p-NP) in presence of excess amount of sodium borohydride was used as a model reaction. Synergistic enhancement in photocatalytic activities could be observed with the Au-Pd/FLG being the best catalyst when compared to the nanoparticles of Au, Pd, Au-Pd and their nanocomposites with FLG (Au/FLG and Pd/FLG). Normalized rate constant (9.77 s−1 mg−1) of the Au-Pd/FLG was quite high compared to most other Au and Pd based nanomaterials that are reported in the literature. The enhanced photocatalytic activity of the Au-Pd/FLG nanocomposite could be correlated with its enhanced visible light activity. Moreover, enhanced adsorption of the reactant molecules and better charge transfer of the nanocomposite are also reasons for the observed photocatalytic activities of the Au-Pd/FLG nanocomposite.

Different nanomaterials possessing localized surface plasmon resonance (LSPR) such as Ag, Au, Cu, Ti are considered as valuable tools in biomedicine and biotechnology, especially as signal enhancers in different immunoassays. In particular, silver nanoparticles as one of the most effective plasmonic metamaterials are widely used for the development of analytical detection methods, where nanoparticles either act as labels or exhibit intrinsic enzymatic activity (e.g., peroxidase or catalase-like). Silver nanowires (AgNWs) synthesized through polyol synthesis are stable nanomaterials with a highly reactive surface. Here we show that AgNWs possess intrinsic peroxidase-like activity with three commonly used substrates – 3,3’,5,5’-tetramethybenzidine (TMB), o-phenylenediamine (OPD), or diaminobenzidine (DAB) both in precipitating and non-precipitating modes. Moreover, we showed that AgNWs together with OPD can serve as a robust hydrogen peroxide sensor and pH-sensor: AgNW peroxidase-like activity increases linearly with pH. The capabilities of AgNWs as enzyme-like labels were demonstrated in competitive enzyme-linked immunoassay with chloramphenicol (CAP) biosensing with the 0.36 µM (0.15 µg/mL) detection limit. Moreover, the LSPR property of AgNW allows using them as optical labels for the visualization of antibody-hapten interaction – the fact was confirmed with CAP detection in the lateral flow test within the 0.12 ÷ 88 µM working concentration range. Taking into account the unique stability of AgNWs (AgNW were stable for more than two years at room temperature in water without any preservatives and light protection), AgNWs should be considered as robust, convenient, and reliable optical labels for the development of different commercial assays for the wide spectrum of biological applications.

Plasmonic nanoparticles can provide great utility for the construction of advanced optical and electrical sensors. Herein, we present a versatile sensing strategy that can perform triple-mode detection of organophosphorus pesticides (OPPs) based on carbon dots (CDs)-participated silver deposition on gold nanoparticles (AuNPs). Simply, a hybrid system composed of AuNPs, CDs, and silver ions in phosphate-buffered saline (AuNPs/Ag+/CDs) is designed, and alkaline phosphatase (ALP) is used to catalytically produce l-ascorbic acid, which reduces silver ions to metallic silver on the surface of AuNPs. OPPs can simultaneously modulate triple optical signals, including light absorption, fluorescence, and Rayleigh scattering of the AuNPs/Ag+/CDs hybrid, by inhibiting the activity of ALP, and thus colorimetry, fluorescence, and resonance Rayleigh scattering methods for OPPs are established. Meanwhile, the mechanism of spectral change involved in the three optical signals is investigated in detail. In addition, the proposed detection system is used for the determination of OPPs in vegetables with satisfactory results. The nanohybrid-platform-integrated triple-signal readout provides not only approaches for OPPs detection but also insight for the development of optical sensors. [ABSTRACT FROM AUTHOR]

The combination of plasmonic nanoparticles and optical microcavities has attracted broad interest for both fundamental and applied studies. However, the conventional scheme of plasmonic nanoparticles being located at microcavity outer surfaces suffers from serious problems such as significant radiative/scattering losses and chemical/mechanical instabilities. Here, silver nanoparticles (NPs) and dispersed ions embedded in nanomembrane‐formed whispering‐gallery‐mode (WGM) microtube cavities are prepared by ion implantations as compact and stable optoplasmonic microcavities. Upon low ion fluence implantation, dispersed silver ions are generated in the tube cavity wall, leading to a redshift of the WGM resonant cavity modes due to the increased refractive index. The silver ions start to aggregate into plasmonic NPs in the cavity wall when increasing implantation ion fluences. The competition and transition between redshift induced by the refractive index increase and blueshift induced by the formation of plasmonic NPs are investigated. Moreover, quality factor enhancement of the WGM modes is observed owing to the improved light confinement caused by the presence of NPs. This work demonstrates a convenient approach for the fabrication of stable optoplasmonic microcavities and fine tuning of resonant modes, indicating wide applications such as wavelength selective tuning and enhanced light–matter interactions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Designing drug-free polyvinyl alcohol coated stable silver triangular nano-prisms (PVA-SNT). • Computational simulation of optical and photothermal properties with high in vivo experimental similarity. • Stable PVA-SNT enables photoacoustic imaging-guided photothermal therapy of breast cancer. • PVA-SNT exhibits enhanced photostability and high photothermal conversion efficiency. The advanced features of plasmonic nanomaterials enable initial high accuracy detection with different therapeutic intervention. Computational simulations could estimate the plasmonic heat generation with a high accuracy and could be reliably compared to experimental results. This proposed combined theoretical-experimental strategy may help researchers to better understand other nanoparticles in terms of plasmonic efficiency and usability for future nano-theranostic research. To develop innovative computationally-driven approach to quantify any plasmonic nanoparticles photothermal efficiency and effects before their use as therapeutic agents. This report introduces drug free plasmonic silver triangular nanoprisms coated with polyvinyl alcohol biopolymer (PVA-SNT), for in vivo photoacoustic imaging (PAI) guided photothermal treatment (PTT) of triple-negative breast cancer mouse models. The synthesized PVA-SNT nanoparticles were characterized and a computational electrodynamic analysis was performed to evaluate and predict the optical and plasmonic photothermal properties. The in vitro biocompatibility and in vivo tumor abalation study was performed with MDA-MB-231 human breast cancer cell line and in nude mice model. The drug free 140 μg∙mL−1 PVA-SNT nanoparticles with 1.0 W∙cm−2 laser irradiation for 7 min proved to be an effective and optimized theranostic approach in terms of PAI guided triple negative breast cancer treatment. The PVA-SNT nanoparticles exhibits excellent biosafety, photostability, and strong efficiency as PAI contrast agent to visualize tumors. Histological analysis and fluorescence-assisted cell shorter assay results post-treatment apoptotic cells, more importantly, it shows substantial damage to in vivo tumor tissues, killing almost all affected cells, with no recurrence. This is a first complete study on computational simulations to estimate the plasmonic heat generation followed by drug free plasmonic PAI guided PTT for cancer treatment. This computationally-driven theranostic approach demonstrates an innovative thought regarding the nanoparticles shape, size, concentration, and composition which could be useful for the prediction of photothermal heat generation in precise nanomedicine applications. [ABSTRACT FROM AUTHOR]

A tenfold increase in the quantum yield of defect luminescence in the region of 750 nm with a simultaneous increase in its decay time from 4 to 200 ns, due to decoration of surface of quantum dots (QDs) Ag2S/SiO2 (5.0 ± 1.5 nm) with Au nanoparticles (NPs) (2.0 ± 0.5 nm). Based on analysis of the luminescence kinetics at temperatures of 77 and 300 K, it was concluded that such a nonspecific manifestation of the plasmon–exciton interaction is caused by the influence of polarization effects from Au NPs on the properties of shallow traps involved in the formation of the defect luminescence kinetics of Ag2S/SiO2 QDs. [ABSTRACT FROM AUTHOR]

Herein, the structures of three types of silver nanoparticles embedded within the rear antireflection layer of silicon bifacial solar cells are investigated by performing a three-dimensional simulation based on the finite-element method. Regarding aesthetics, impressive colours are achieved with an optical gain by using plasmonic nanoparticles with a size of approximately 10 nm, which are usually considered to be unbeneficial to solar cells. The rear optical spectra and short-circuit current gain/loss of the solar cells are analysed, well reproducing the main performance features observed in the previous experiment. The underlying mechanism is that the hybrid plasmonic antireflection coating layer presents particular interference patterns modulated due to the dramatic plasmonic resonance, which compensate for the absorption loss in particles for certain structure parameters. These results pave the way towards the application of plasmonic particles with a much smaller size and open up a road for designing efficient colourful building integrated photovoltaics. [ABSTRACT FROM AUTHOR]

The formation of well‐defined, functional surfaces that incorporate the unique properties of inorganic nanoparticles (NPs) requires robust and scalable fabrication strategies. Herein, we report a methodology for the decoration of polymer molds with plasmonic (gold) nanoparticle arrays. Wrinkled soft templates were used to assemble gold NPs (74 nm) into line arrays. These pre‐formed nanoparticle arrays were transferred in a subsequent step onto polycarbonate molds via an injection molding process. Scanning electron microscopy analysis revealed the structural fidelity of the pattern structure upon transfer. The preservation of the optical functionality of the gold nanoparticle line arrays was proven by surface‐enhanced Raman scattering (SERS) experiments. The reported strategy of nanoparticle pattern transfer to polymer bodies by this robust process is expected to prove useful for the fabrication of polymer surfaces with tailored optical functionality. [ABSTRACT FROM AUTHOR]

Artificially designed heterostructures formed by close conjunctions of plasmonic metal nanoparticles (PNPs) and non-plasmonic (2D) lamellar nanostructures are receiving extensive interest. The synergistic interactions of the nanounits induce the manifestation of localized surface plasmon resonance (LSPR) in plasmonic metals in the specific environment of the 2D-light absorbing matrix, impacting their potential in plasmon enhanced catalysis. Specifically, layered double hydroxides (LDH) with the advantages of their unique 2D-layered structure, tuned optical absorption, ease of preparation, composition diversity, and high surface area, have emerged as very promising candidates for obtaining versatile and robust catalysts. In this review, we cover the available PNPs/LDH heterostructures, from the most used noble-metals plasmonic of Au and Ag to the novel non-noble-metals plasmonic of Cu and Ni, mainly focusing on their synthesis strategies toward establishing a synergistic response in the coupled nanounits and relevant applications in plasmonic catalysis. First, the structure–properties relationship in LDH, establishing the desirable features of the 2D-layered matrix facilitating photocatalysis, is shortly described. Then, we address the recent research interests toward fabrication strategies for PNPs/support heterostructures as plasmonic catalysts. Next, we highlight the synthesis strategies for available PNPs/LDH heterostructures, how these are entangled with characteristics that enable the manifestation of the plasmon-induced charge separation effect (PICS), co-catalytic effect, or nanoantenna effect in plasmonic catalysis with applications in energy related and environmental photocatalysis. Finally, some perspectives on the challenges and future directions of PNPs/LDHs heterostructures to improve their performance as plasmonic catalysts are discussed. [ABSTRACT FROM AUTHOR]

Solution‐based surface‐enhanced Raman scattering (SERS) detection typically involves the aggregation of citrate‐stabilized Au nanoparticles into colloidal assemblies. Although this sensing methodology offers excellent prospects for sensitivity, portability, and speed, it is still challenging to control the assembly process by a salting‐out effect, which affects the reproducibility of the assemblies and, therefore, the reliability of the analysis. This work presents an alternative approach that uses a bolaform surfactant, B20, to induce the plasmonic assembly. The decrease of the surface charge and the bridging effect, both promoted by the adsorption of B20, are hypothesized as the key points governing the assembly. Furthermore, molecular dynamic simulations supported the bridging effect of the B20 by showing the preferential bridging of surfactant monomers between two adjacent Au(111) slabs. The colloidal assemblies showed excellent SERS capabilities towards the rapid, on‐site detection and quantification of beta‐blockers and analgesic drugs in the nanomolar regime, with a portable Raman device. Interestingly, the application of state‐of‐the‐art convolutional neural networks, such as ResNet, allows a 100% accuracy in classifying the concentration of different binary mixtures. Finally, the colloidal approach was successfully implemented in a millifluidic chip allowing the automation of the whole process, as well as improving the performance of the sensor in terms of speed, reliability, and reusability without affecting its sensitivity. [ABSTRACT FROM AUTHOR]

In this study, graphene oxide/gold/methylene blue (GO/Au/MB) ternary composites were synthesized and characterized through UV–vis, FTIR, XRD, XPS, SEM, and TEM analyses towards plasmon-enhanced singlet oxygen (1O2) generation. Through using gold nanoparticles and MB photosensitizers, the visible light adsorption capability of GO was enhanced by 115%. Moreover, applying this ternary composite as a photocatalyst under visible light interestingly revealed a drastic step-increase of 14% (i.e., from 9 to 23%) in the conversion of photooxygenation of Anthracene. This behavior was rationalized using finite-difference time-domain (FDTD) simulations which confirms the plasmonic field of gold nanoparticles with a diameter of 16 nm obtained from TEM. Time-dependent density functional theory (TD-DFT) calculations suggest that the presence of an electric field can favor the intersystem crossing of methylene blue to enhance 1O2 generation. [ABSTRACT FROM AUTHOR]

Plasmon enhanced electrochemistry (PEEC), where specific electrochemical reactions are promoted due to the reduced energy barrier of the reaction processes by the light excited "hot carriers" of the plasmonic nanoparticles, has aroused tremendous interest in recent years. A deep understanding of the PEEC process becomes a key issue for facilitating PEEC catalyst design and improving PEEC performance. This concept article begins with a brief discussion of the macroscopic electrochemical method of PEEC study of the plasmonic nanoparticle ensembles. Following that, we highlight two electrochemical techniques that may possess single nanoparticle sensitivity, i. e., scanning electrochemical microscope and nano‐impact electrochemistry. The pros and cons of each technique are discussed and an outlook is given. We hope to provide the readers with the current status of PEEC to evoke reflections regarding the reaction mechanisms, performance improvement, and the utilizations to important systems. [ABSTRACT FROM AUTHOR]

To enhance the photoluminescence of silicon nanocrystals, gold nanoparticles are incorporated into a silicon oxide matrix by excimer laser-based implantation. By this simple method, the gold nanoparticles are placed under the surface in a scratch resistant manner. Optical absorption measurements and SEM analyses show the essential properties of the gold implantation. The silicon nanocrystals are characterized by Raman and photoluminescence measurements. A more than twofold enhancement of the photoluminescence of the silicon nanocrystals, depending on the number of applied laser pulses during gold implantation, is achieved. [ABSTRACT FROM AUTHOR]

Light-emitting diodes (LED) are widely employed in display applications and lighting systems. Further research on LED that incorporates carbon nanostructures and metal nanoparticles exhibiting surface plasmon resonance has demonstrated a significant improvement in device performance. These devices offer lower turn-on voltages, higher external quantum efficiencies, and luminance. De facto, plasmonic nanoparticles, such as Au and Ag have boosted the luminance of red, green, and blue emissions. When combined with carbon nanostructures they additionally offer new possibilities towards lightweight and flexible devices with better thermal management. This review surveys the diverse possibilities to combine various inorganic, organic, and carbon nanostructures along with plasmonic nanoparticles. Such combinations would allow an enhancement in the overall properties of LED.

The rational design and dispersion engineering of plasmonic colloid gratings are mainly responsible for advancing refractive index sensors. Herein, a 1D colloidal plasmonic lattice composed of nanoparticle dimer chains fabricated by a combination of interference lithography, soft molding, and colloidal self‐assembly is studied. The bottom‐up approach affords centimeter‐scale arrays of high‐quality colloidal nanoparticles with resonances in the visible range. Demonstrating a special case of collective plasmonic coupling called out‐of‐plane lattice resonance (OPLR) is focused on. Such OPLRs are excited, solely under oblique illumination with transverse magnetic polarization, and these findings with electromagnetic simulations are supported. In addition, it is experimentally found that such resonances are spectrally narrow with a linewidth of 8.08 ± 0.6 nm and have a quality factor of 78.49 ± 5.7, an enhancement by a factor of 11.62 compared with a single particle. The oblique incidence provides field enhancement outside the substrate plane, which is more accessible and sensitive to a surrounding analyte. A simple glycerol–water mixture as a model system to demonstrate this enhanced sensitivity and discuss the potential for a sensing application in an asymmetric refractive index environment is demonstrated. Beyond these sensing applications, this platform has the potential to enhance other processes, such as hot carrier injection or coherent energy transfer.

Understanding and optimising the mechanisms of generation and extraction of hot carriers in plasmonic heterostructures is important for applications in new types of photodetectors, photochemistry and photocatalysis, as well as nonlinear optics. Here, we show using transient dynamic measurements that the relaxation of the excited hot-carriers in Au/Pt hetero-nanostructures is accelerated through the transfer pathway from Au, where they are generated, to Pt nanoparticles, which act as a hot-electron sink. The influence of the environment on the dynamics was also demonstrated. The time-resolved photoluminescence measurements confirm the modified hot-electron dynamics, revealing quenching of the photoluminescence signal from Au nanoparticles in the presence of Pt and an increased photoluminescence lifetime. These observations are signatures of the improved extraction efficiency of hot-carriers by the Au/Pt heterostructures. The results give insight into the time-dependent behaviour of excited compound nanoscale systems and provide a way of controlling the relaxation mechanisms involved, with important consequences for engineering nonlinear optical response and hot-carrier-assisted photochemistry.

Surface-enhanced Raman scattering (SERS) has been extensively applied to detect complex analytes due to its ability to enhance the fingerprint signals of molecules around nanostructured metallic surfaces. Thus, it is essential to design SERS-active nanostructures with abundant electromagnetic hotspots in a probed volume according to the dimensions of the analytes, as the analytes must be located in their hotspots for maximum signal enhancement. Herein, we demonstrate a simple method for detecting robust SERS signals from multi-scaled bioanalytes, regardless of their dimensions in the liquid state, through a photothermally driven co-assembly with colloidal plasmonic nanoparticles as signal enhancers. Under resonant light illumination, plasmonic nanoparticles and analytes in the solution quickly assemble at the focused surface area by convective movements induced by the photothermal heating of the plasmonic nanoparticles without any surface modification. Such collective assemblies of plasmonic nanoparticles and analytes were optimized by varying the optical density and surface charge of the nanoparticles, the viscosity of the solvent, and the light illumination time to maximize the SERS signals. Using these light-induced co-assemblies, the intrinsic SERS signals of small biomolecules can be detected down to nanomolar concentrations based on their fingerprint spectra. Furthermore, large-sized biomarkers, such as viruses and exosomes, were successfully detected without labels, and the complexity of the collected spectra was statistically analyzed using t-distributed stochastic neighbor embedding combined with support vector machine (t-SNE + SVM). The proposed method is expected to provide a robust and convenient method to sensitively detect biologically and environmentally relevant analytes at multiple scales in liquid samples. A method utilizing photothermally driven assembly of colloidal plasmonic nanoparticles and multi-scaled bioanalytes is presented for enhancing SERS signals. This approach enables label-free detection of various biomolecules, including small biomolecules and larger biomarkers like viruses and exosomes, offering a robust and sensitive means to detect analytes in liquid samples. [Display omitted] [ABSTRACT FROM AUTHOR]

Surface‐enhanced Raman scattering (SERS) is a powerful sensing technique. However, the employment of SERS sensors in practical applications is hindered by high fabrication costs from processes with limited scalability, poor batch‐to‐batch reproducibility, substrate stability, and uniformity. Here, highly scalable and reproducible flame aerosol technology is employed to rapidly self‐assemble uniform SERS sensing films. Plasmonic Ag nanoparticles are deposited on substrates as nanoaggregates with fine control of their interparticle distance. The interparticle distance is tuned by adding a dielectric spacer during nanoparticle synthesis that separates the individual Ag nanoparticles within each nanoaggregate. The dielectric spacer thickness dictates the plasmonic coupling extinction of the deposited nanoaggregates and finely tunes the Raman hotspots. By systematically studying the optical and morphological properties of the developed SERS surfaces, structure–performance relationships are established and the optimal hot‐spots occur for interparticle distance of 1 to 1.5 nm among the individual Ag nanoparticles, as also validated by computational modeling, are identified for the highest signal enhancement of a molecular Raman reporter. Finally, the superior stability and batch‐to‐batch reproducibility of the developed SERS sensors are demonstrated and their potential with a proof‐of‐concept practical application in food‐safety diagnostics for pesticide detection on fruit surfaces is explored. [ABSTRACT FROM AUTHOR]

The exceptionally large charge‐carrier density in photoexcited plasmonic nanoparticles (NPs) can be used for the making and breaking of high‐energy chemical bonds, which forms the basis of plasmonic photocatalysis. This review showcases the roadmap of important events and major bottlenecks in plasmonic photocatalysis, along with highlighting a few probable solutions for achieving the desired targets. The review starts with a discussion on various excitation and relaxation pathways, followed by the section on initial use of plasmons in enhancing the photocatalytic properties of semiconductor materials. Next, the sole use of plasmonic NPs in driving useful and industrially relevant chemical transformations is discussed. This is followed by a critical assessment of various challenges and opportunities in the area, along with a discussion on emerging experiments capable of overcoming these challenges. Decades of research have provided a clear understanding on charge generation and decay processes in plasmonic NPs. However, achieving an efficient separation and utilization of charge carriers is still a roadblock in realizing the full potential of plasmonic NPs in catalysis. In short, doing chemistry with plasmons is attractive; but it is high time to develop strategies that can quantitatively utilize the charge carriers for driving chemical transformations in a selective and efficient way. [ABSTRACT FROM AUTHOR]