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Transferring traditional plasmonic noble metal nanomaterials from the laboratory to industrial production has remained challenging due to the high price of noble metals. The development of cost-effective non-noble-metal alternatives with outstanding plasmonic properties has therefore become essential. Herein, we report on the gram-scale production of differently shaped TiN nanoparticles with strong plasmon-enabled broadband light absorption, including differently sized TiN nanospheres, nanobipyramids, and nanorod arrays. The TiN nanospheres and nanobipyramids are further coembedded in highly porous poly(vinyl alcohol) films to function as a photothermal material for solar seawater desalination. A seawater evaporation rate of 3.8 kg m–2h–1is achieved, which marks the record performance among all plasmonic solar seawater desalination systems reported so far. The removal percentage of phenol reaches 98.3%, which is attributed to the joint action of the excellent photocatalytic ability and the superhydrophilicity of the porous TiN-based composite film.

Superposing two or more periodic structures to form moiré patterns is emerging as a promising platform to confine and manipulate light. However, moiré-facilitated interactions and phenomena have been constrained to the vicinity of moiré lattices. Here we report on the observation of ultralong-range coupling between photonic lattices in bilayer and multilayer moiré architectures mediated by dark surface lattice resonances in the vertical direction. We show that two-dimensional plasmonic nanoparticle lattices enable twist-angle-controlled directional lasing emission, even when the lattices are spatially separated by distances exceeding three orders of magnitude of lattice periodicity. Our discovery of far-field interlattice coupling opens the possibility of using the out-of-plane dimension for optical manipulation on the nanoscale and microscale.

Interactions between the microbiota and their colonized environments mediate critical pathways from biogeochemical cycles to homeostasis in human health. Here we report a soil-inspired chemical system that consists of nanostructured minerals, starch granules and liquid metals. Fabricated via a bottom-up synthesis, the soil-inspired chemical system can enable chemical redistribution and modulation of microbial communities. We characterize the composite, confirming its structural similarity to the soil, with three-dimensional X-ray fluorescence and ptychographic tomography and electron microscopy imaging. We also demonstrate that post-synthetic modifications formed by laser irradiation led to chemical heterogeneities from the atomic to the macroscopic level. The soil-inspired material possesses chemical, optical and mechanical responsiveness to yield write–erase functions in electrical performance. The composite can also enhance microbial culture/biofilm growth and biofuel production in vitro. Finally, we show that the soil-inspired system enriches gut bacteria diversity, rectifies tetracycline-induced gut microbiome dysbiosis and ameliorates dextran sulfate sodium-induced rodent colitis symptoms within in vivo rodent models.

This Letter describes strong coupling between a plasmonic nanoparticle (NP) lattice cavity and Soret excitons in a metal–organic framework (MOF) film. In optical transmission measurements, we observed a lower polariton mode that can be spectrally tuned by infiltrating MOF pores with solvents of different refractive index. Using transient absorption spectroscopy, both the lower and upper polariton modes can be resolved, with an estimated Rabi splitting of ∼300 meV, nearly twice that of other plasmonic cavity–organic emitter systems. The polariton modes decay more rapidly than that of the uncoupled exciton. This hybrid system highlights the advantages of open plasmonic cavities for tunable coupling and the use of transient absorption spectroscopy to identify polariton modes.

This Letter describes strong coupling of densely packed molecular emitters in metal–organic frameworks (MOFs) and plasmonic nanoparticle (NP) lattices. Porphyrin-derived ligands with small transition dipole moments in an ordered MOF film were grown on Ag NP arrays. Angle-resolved optical measurements of the MOF-NP lattice system showed the formation of a polariton that is lower in energy and does not cross the uncoupled MOF Q1band. Modeling predicted the upper polariton energy and a calculated Rabi splitting of 110 meV. The coupling strength was systematically controlled by detuning the plasmon energy by changing the refractive index of the solvents infiltrating the MOF pores. Through transient absorption spectroscopy, we found that the lower polariton decays quickly at shorter time scales (<500 ps) and slowly at longer times because of energy transfer from the upper polariton. This hybrid system demonstrates how MOFs can function as an accessible excitonic material for polariton chemistry.

This paper describes an evolutionary approach to design flat multiwavelength achromatic lenses based on subwavelength plasmonic nanoparticles. Our lattice evolution algorithm achieved desired optical responses by tuning the arrangement of the phase units on a discrete square lattice. Lattice lenses consisting of a single type of nanoparticle could operate at any wavelength in the visible to near-infrared regime (540–1000 nm) by tailoring the localized surface plasmon resonance. When the unit cells were expanded to anisotropic particle shapes, the planar optics could selectively focus light depending on the polarization of incident light. Finally, the algorithm realized efficient multiobjective optimization and produced achromatic lattice lenses at up to three wavelengths (λ = 600 nm, λ = 785 nm, and λ = 980 nm) using multiple different nanoparticle shapes.

This paper reports hierarchical hybridization as a mode-mixing scheme to account for the unique optical properties of non-Bravais lattices of plasmonic nanoparticles (NPs). The formation of surface lattice resonances (SLRs) mediated by localized surface plasmons (LSPs) of different multipolar orders (dipole and quadrupole) can result in asymmetric electric near-field distributions surrounding the NPs. This asymmetry is because of LSP hybridization at the individual NP level from LSPs of different multipole order and at the unit cell level (NP dimer) from LSPs of the same multipole order. Fabricated honeycomb lattices of silver NPs exhibit ultrasharp SLRs at the Γ point that can also facilitate nanolasing. Modeling of the stimulated emission process revealed that the multipolar component of the lattice plasmon mode was responsible for feedback for lasing. By leveraging multipolar LSP responses in Al NP lattices, we achieved two distinct Γ point band-edge modes from a single honeycomb lattice. This work highlights how multipolar LSP coupling in plasmonic lattices with a non-Bravais symmetry has important implications for the design of SLRs and their associated plasmonic near-field distributions. These relatively unexplored degrees of freedom can decrease both ohmic and radiative losses in nanoscale systems and enable SLRs to build unanticipated connections among photonics and nanochemistry.

Plasmonic nanostructures have shown immense potential in boosting photocatalytic performance through hot charge carrier injection, electric field enhancement, and local photothermal conversion because of their localized surface plasmon resonance (LSPR) properties. The intriguing feature of the hot carrier transfer mechanism can be classified into three channels, which are indirect and direct charge transfer, intramolecular excitation, and resonant energy transfer. With abundant reserves and favorable stability, nonmetal plasmonic nanostructures are promising alternatives for high-cost and rare noble metals. Nonmetal plasmonic photocatalysts, including metal oxides, metal nitrides, and metal chalcogenides, with broad and adjustable light harvesting capabilities in the ultraviolet–visible–near-infrared region, have been widely used in solar energy conversion and environmental remediation fields. In this Perspective, recent developments of nonmetal plasmonic photocatalysts are briefly summarized. Challenges and future research on constructing highly efficient nonmetal plasmonic photocatalysts are also discussed.

Because of translational symmetry, electromagnetic fields confined within 2D periodic optical structures can be represented within the first Brillouin zone (BZ). In contrast, the wavevectors of scattered electromagnetic fields outside the lattice are constrained by the 3D light cone, the free-photon dispersion in the surrounding medium. Here, we report that light-cone surface lattice resonances (SLRs) from plasmonic nanoparticle lattices can be used to observe the radiated electromagnetic fields from extended BZ edges. Our coupled dipole radiation theory reveals how lattice geometry and induced surface plasmon dipole orientation affect angular distributions of the radiated fields. Using dye molecules as local dipole emitters to excite the light-cone SLR modes, we experimentally identified high-order BZ edges by directional, in-plane lasing emission. These results provide insight into nanolaser architectures that can emit at multiple wavelengths and in-plane directions simply by rotating the nanocavity lattice.

This paper describes the light-directed functionalization of anisotropic gold nanoparticles with different thiolated-DNA oligomer (oligo) sequences. The starting nanoconstructs are gold nanostars (AuNS) uniformly grafted with one oligo sequence that are then exposed to fs-laser pulses at the plasmon resonance of the branches. The excitation selectively cleaves Au–S bonds at the tips of the branches to create vacant areas for functionalization with a different thiolated oligo sequence. Nanoconstructs synthesized by this approach present one oligo sequence on the AuNS body and branches and a different sequence at the tips. This process enables the formation of nanoparticle superstructures consisting of AuNS cores and small Au satellite nanoparticles at controlled locations after DNA hybridization. Our strategy enables selective oligo presentation at the single-particle level and opens prospects for sophisticated design of nanoscale assemblies that are important in a wide range of biological applications.

This paper describes a computational imaging platform to determine the orientation of anisotropic optical probes under differential interference contrast (DIC) microscopy. We established a deep-learning model based on data sets of DIC images collected from metal nanoparticle optical probes at different orientations. This model predicted the in-plane angle of gold nanorods with an error below 20°, the inherent limit of the DIC method. Using low-symmetry gold nanostars as optical probes, we demonstrated the detection of in-plane particle orientation in the full 0–360° range. We also showed that orientation predictions of the same particle were consistent even with variations in the imaging background. Finally, the deep-learning model was extended to enable simultaneous prediction of in-plane and out-of-plane rotation angles for a multibranched nanostar by concurrent analysis of DIC images measured at multiple wavelengths.

This work reports a massively parallel approach for synthesizing inorganic nanoparticles (Au, Ag, Se, and mixed oxides of Cu, Co, Ni, Ge, and Ta) based upon lithographically generated arrays of square pyramidal nanoholes, which serve as nanoreactors. Particle precursor-containing polymers are spin-coated onto the nanoreactors, which upon dewetting generate a morphology of isolated polymer droplets in each nanoreactor. This dewetting process yields a well-defined and precisely controlled volume of polymer and therefore particle precursor in each nanoreactor. Subsequent stepwise annealing (first at 150 °C and then at 500 °C) yields arrays of monodisperse, site-isolated particles with sub-5 nm position control. By varying the precursor loading of the polymer, particle size can be systematically controlled in the 7–30 nm range. This work not only introduces the concept of merging block copolymer inks with nanohole arrays in the synthesis of nanoparticles but also underscores the value of the nanoreactor shape in controlling resulting particle position.

Rationally assembled nanostructures exhibit distinct physical and chemical properties beyond their individual units. Developments in nanofabrication techniques have enabled the patterning of a wide range of nanomaterial designs over macroscale (>in.2) areas. Periodic metal nanostructures show long-range diffractive interactions when the lattice spacing is close to the wavelength of the incident light. The collective coupling between metal nanoparticles in a lattice introduces sharp and intense plasmonic surface lattice resonances, in contrast to the broad localized resonances from single nanoparticles. Plasmonic nanoparticle lattices exhibit strongly enhanced optical fields within the subwavelength vicinity of the nanoparticle unit cells that are 2 orders of magnitude higher than that of individual units. These intense electromagnetic fields can manipulate nanoscale processes such as photocatalysis, optical spectroscopy, nonlinear optics, and light harvesting.

This paper describes a reconfigurable metalens system that can image at visible wavelengths based on arrays of coupled plasmonic nanoparticles. These lenses manipulated the wavefront and focused light by exciting surface lattice resonances that were tuned by patterned polymer blocks on single-particle sites. Predictive design of the dielectric nanoblocks was performed using an evolutionary algorithm to create a range of three-dimensional focusing responses. For scalability, we demonstrated a simple technique for erasing and writing the polymer nanostructures on the metal nanoparticle arrays in a single step using solvent-assisted nanoscale embossing. This reconfigurable materials platform enables tunable focusing with diffraction-limited resolution and offers prospects for highly adaptive, compact imaging.

Gold nanorods are promising nanoparticle-orientation sensors because they exhibit wavelength and angle-dependent optical patterns in their differential interference contrast (DIC) microscopy images. In this paper, we report a finite-difference time-domain method to simulate DIC images using nanorods as model probes. First, we created a DIC image library of nanorods as a function of imaging wavelength and rotation angle that showed good agreement with experimental results. Second, we used this simulation tool to explain why the patterns inverted from bright to dark when the imaging wavelength increased from below to above the plasmon resonance of the nanorod. We found that this intensity inversion resulted from reversal in the electric field direction depending on wavelength relative to the nanorod plasmon resonance. Finally, we showed that this DIC contrast inversion is a general phenomenon by measuring and simulating DIC images from gold nanorods of different sizes and gold nanostars.

In this issue of Chem Catalysis, Wang et al. have constructed a mechanically driven triboelectric plasma jet system for artificial nitrogen fixation, achieving a superior fixation performance at room temperature and atmospheric pressure. The dominant mechanism for nitrogen fixation in this work is attributed to the vibrationally excited dissociation process.

Privacy protection is a growing concern in the digital era, with machine vision techniques widely used throughout public and private settings. Existing methods address this growing problem by, e.g., encrypting camera images or obscuring/blurring the imaged information through digital algorithms. Here, we demonstrate a camera design that performs class-specific imaging of target objects with instantaneous all-optical erasure of other classes of objects. This diffractive camera consists of transmissive surfaces structured using deep learning to perform selective imaging of target classes of objects positioned at its input field-of-view. After their fabrication, the thin diffractive layers collectively perform optical mode filtering to accurately form images of the objects that belong to a target data class or group of classes, while instantaneously erasing objects of the other data classes at the output field-of-view. Using the same framework, we also demonstrate the design of class-specific permutation and class-specific linear transformation cameras, where the objects of a target data class are pixel-wise permuted or linearly transformed following an arbitrarily selected transformation matrix for all-optical class-specific encryption, while the other classes of objects are irreversibly erased from the output image. The success of class-specific diffractive cameras was experimentally demonstrated using terahertz (THz) waves and 3D-printed diffractive layers that selectively imaged only one class of the MNIST handwritten digit dataset, all-optically erasing the other handwritten digits. This diffractive camera design can be scaled to different parts of the electromagnetic spectrum, including, e.g., the visible and infrared wavelengths, to provide transformative opportunities for privacy-preserving digital cameras and task-specific data-efficient imaging.

The adsorption of a surfactant mixture, based on an anionic surfactant, sodium dodecyl benzenesulfonate (SDBS) and a nonionic surfactant (Triton X-100, or TX100), on alumina nanoparticles was determined by solution depletion method combined with spectrometric measurement. It is shown that the light scattering, originated from the residual adsorbent alumina particles in the supernatant after centrifugation separation, interferes with the measurements of absorbance of the surfactant molecules, and therefore constitutes an error source for determination of the surfactant concentration in the supernatant by spectrometric means. The intensity of this light scattering, namely the influence of the residual alumina nanoparticles upon the surfactant adsorption, was related to the surfactant adsorption and its equilibrium concentration and varied among a batch. In this paper we report a Kalman filter method in order to eliminate the variational scattering background caused by non-separated residual alumina nanoparticles in each supernatant. This method is of interest as it is simple, easy to carry out and of high precision.

A study of the enhancement effect on the fluorescence intensity of the Eu3+–-thenoyltrifluoroacetone (TTA)–-cetyltri–-methylammonium bromide (CTMAB) and the Dy3+ pyrocatechol–-3,5-disulphonic acid (Tiron) systems by Y3+has been carried out. In the presence of yttrium the fluorescence intensity of the systems was enhanced by a factor of about 100 and 15, respectively. The fluorescence intensity was a linear function of the concentration of europium or dysprosium in the range 1.0 × 10-10–-1.0 × 10-8mol dm-3 and 8.0 × 10-8–-9.0 × 10-6mol dm-3, respectively. The detection limit was 1.0 × 10-11mol dm-3 and 1.0 × 10-10mol dm-3, respectively. The standard addition method was used for the determination of europium or dysprosium in rare earth oxides and gave satisfactory results. The mechanism of enhanced fluorescence was proposed.

The signal-to-noise ratio and detection limit of a series piezoelectric quartz crystal (SPQC) in non- electrolyte liquid were investigated experimentally and explained theoretically. It is shown that the noise level of the SPQC depends greatly on the variation of solution temperature. The detection limit of the SPQC increases with increasing permittivity, and it decreases slightly with a larger cell constant. The SPQC is applied to the rapid determination of water in edible oils with a detection limit of 0.05 g L.

AbstractA method is described for the determination of ferrocene and its derivatives by the fluorescence quenching of europium-2-benzoyl-indan-1,3-dione-cetyltrimethyl-ammonium bromide(CTMAB) system. Under the optimum conditions, the decrease of the fluorescence intensity was a linear function of the concentration of ferrocene or its derivatives in the range 1.0 × 10−6-1.0 × 10−5mol/L. The detection limit was 1.0 × 10−7mol/L. The system was used for the determination of ferrocene n-heptyl β-diketone, with satisfactory results.