Showing papers on "Plasmon published in 2022"

Non-Noble Plasmonic Metal-Based Photocatalysts.

Abstract: Solar-to-chemical energy conversion via heterogeneous photocatalysis is one of the sustainable approaches to tackle the growing environmental and energy challenges. Among various promising photocatalytic materials, plasmonic-driven photocatalysts feature prominent solar-driven surface plasmon resonance (SPR). Non-noble plasmonic metals (NNPMs)-based photocatalysts have been identified as a unique alternative to noble metal-based ones due to their advantages like earth-abundance, cost-effectiveness, and large-scale application capability. This review comprehensively summarizes the most recent advances in the synthesis, characterization, and properties of NNPMs-based photocatalysts. After introducing the fundamental principles of SPR, the attributes and functionalities of NNPMs in governing surface/interfacial photocatalytic processes are presented. Next, the utilization of NNPMs-based photocatalytic materials for the removal of pollutants, water splitting, CO2 reduction, and organic transformations is discussed. The review concludes with current challenges and perspectives in advancing the NNPMs-based photocatalysts, which are timely and important to plasmon-based photocatalysis, a truly interdisciplinary field across materials science, chemistry, and physics.

Plasmonic Biosensor With Gold and Titanium Dioxide Immobilized on Photonic Crystal Fiber for Blood Composition Detection

Abstract: This paper proposes a photonic crystal fiber (PCF) based plasmonic biosensor for the detection of various blood compositions like red blood cells (RBCs), hemoglobin (HB), white blood cells (WBCs), plasma, and water. The finite element method (FEM) has been used to simulate and quantitatively evaluate this biosensor. The gold and titanium dioxide coated PCF operates on the surface plasmon resonance (SPR) theory, where the gold layer acts as a plasmonic material, and the titanium dioxide layer improves adhesion between the gold layer and the PCF surface. SPR occurs at the interface between gold and the sensing channel, when the core propagation mode is coupled with the surface plasmon polariton (SPP) mode in the vicinity of the phase-matching point. Due to the occurrence of SPR, the loss peak is noticed in the core propagation mode, and this loss peak is extremely sensitive to the various blood compositions that each have their unique refractive index (RI) poured into the sensing channel of the PCF. The proposed biosensor has maximum wavelength sensitivity of 12400 nm/RIU. However, the maximum amplitude sensitivity is −574.3 RIU−1. Furthermore, with the maximum detection limit of 0.02, the refractive index resolution varies from $8.06\times {10}^{-6} {\mathrm {RIU}}$ to $5.0\times {10}^{-5} {\mathrm {RIU}}$ . As a result, it is safe to say that this biosensor will work admirably in terms of detecting blood compositions. Thus, the proposed biosensor will explore the broad realms of medical diagnostics.

Plasmonic Active “Hot Spots”‐Confined Photocatalytic CO2 Reduction with High Selectivity for CH4 Production

Abstract: Plasmonic nanostructures have tremendous potential to be applied in photocatalytic CO2 reduction, since their localized surface plasmon resonance can collect low‐energy‐photons to derive energetic “hot electrons” for reducing the CO2 activation‐barrier. However, the hot electron‐driven CO2 reduction is usually limited by poor efficiency and low selectivity for producing kinetically unfavorable hydrocarbons. Here, a new idea of plasmonic active “hot spot”‐confined photocatalysis is proposed to overcome this drawback. W18O49 nanowires on the outer surface of Au nanoparticles‐embedded TiO2 electrospun nanofibers are assembled to obtain lots of Au/TiO2/W18O49 sandwich‐like substructures in the formed plasmonic heterostructure. The short distance (< 10 nm) between Au and adjacent W18O49 can induce an intense plasmon‐coupling to form the active “hot spots” in the substructures. These active “hot spots” are capable of not only gathering the incident light to enhance “hot electrons” generation and migration, but also capturing protons and CO through the dual‐hetero‐active‐sites (Au‐O‐Ti and W‐O‐Ti) at the Au/TiO2/W18O49 interface, as evidenced by systematic experiments and simulation analyses. Thus, during photocatalytic CO2 reduction at 43± 2 °C, these active “hot spots” enriched in the well‐designed Au/TiO2/W18O49 plasmonic heterostructure can synergistically confine the hot‐electron, proton, and CO intermediates for resulting in the CH4 and CO production‐rates at ≈35.55 and ≈2.57 µmol g−1 h−1, respectively, and the CH4‐product selectivity at ≈93.3%.

Hybrid Plasmonic Nanomaterials for Hydrogen Generation and Carbon Dioxide Reduction

Abstract: The successful development of artificial photosynthesis requires finding new materials able to efficiently harvest sunlight and catalyze hydrogen generation and carbon dioxide reduction reactions. Plasmonic nanoparticles are promising candidates for these tasks, due to their ability to confine solar energy into molecular regions. Here, we review recent developments in hybrid plasmonic photocatalysis, including the combination of plasmonic nanomaterials with catalytic metals, semiconductors, perovskites, 2D materials, metal–organic frameworks, and electrochemical cells. We perform a quantitative comparison of the demonstrated activity and selectivity of these materials for solar fuel generation in the liquid phase. In this way, we critically assess the state-of-the-art of hybrid plasmonic photocatalysts for solar fuel production, allowing its benchmarking against other existing heterogeneous catalysts. Our analysis allows the identification of the best performing plasmonic systems, useful to design a new generation of plasmonic catalysts.

Liquid crystal-powered Mie resonators for electrically tunable photorealistic color gradients and dark blacks

Abstract: Abstract Taking inspiration from beautiful colors in nature, structural colors produced from nanostructured metasurfaces have shown great promise as a platform for bright, highly saturated, and high-resolution colors. Both plasmonic and dielectric materials have been employed to produce static colors that fulfil the required criteria for high-performance color printing, however, for practical applications in dynamic situations, a form of tunability is desirable. Combinations of the additive color palette of red, green, and blue enable the expression of further colors beyond the three primary colors, while the simultaneous intensity modulation allows access to the full color gamut. Here, we demonstrate an electrically tunable metasurface that can represent saturated red, green, and blue pixels that can be dynamically and continuously controlled between on and off states using liquid crystals. We use this to experimentally realize ultrahigh-resolution color printing, active multicolor cryptographic applications, and tunable pixels toward high-performance full-color reflective displays.

Broadband Polarization-insensitive and Oblique-incidence Terahertz Metamaterial Absorber with Multi-layered Graphene

Abstract: Metamaterial absorbers have been widely studied in the past decade and their performances have been incessantly improved in the practical applications. In this paper, we present a broadband terahertz metamaterial absorber based on graphene-polyimide composite structure, and the structure consists of a metal substrate and graphene layers with different sizes separated by two polyimide dielectric layers. The simulation results show that the absorptance of the absorber is greater than 90% in 0.86–3.54 THz with the fractional bandwidth of 121.8%. The absorptance can be adjusted by changing the chemical potential of graphene. In addition, the absorber is insensitive to polarization and still has robust tolerance for the oblique incidence. The equivalent circuit model based on transmission line is introduced to analyze the physics of the designed absorber and the results are in good agreement with the simulations. We believe that the designed absorber is a potential competitive candidate in terahertz energy harvesting and thermal emission.

Liquid crystal-powered Mie resonators for electrically tunable photorealistic color gradients and dark blacks

Abstract: Abstract Taking inspiration from beautiful colors in nature, structural colors produced from nanostructured metasurfaces have shown great promise as a platform for bright, highly saturated, and high-resolution colors. Both plasmonic and dielectric materials have been employed to produce static colors that fulfil the required criteria for high-performance color printing, however, for practical applications in dynamic situations, a form of tunability is desirable. Combinations of the additive color palette of red, green, and blue enable the expression of further colors beyond the three primary colors, while the simultaneous intensity modulation allows access to the full color gamut. Here, we demonstrate an electrically tunable metasurface that can represent saturated red, green, and blue pixels that can be dynamically and continuously controlled between on and off states using liquid crystals. We use this to experimentally realize ultrahigh-resolution color printing, active multicolor cryptographic applications, and tunable pixels toward high-performance full-color reflective displays.

Operando monitoring of ion activities in aqueous batteries with plasmonic fiber-optic sensors

Abstract: Abstract Understanding ion transport kinetics and electrolyte-electrode interactions at electrode surfaces of batteries in operation is essential to determine their performance and state of health. However, it remains a challenging task to capture in real time the details of surface-localized and rapid ion transport at the microscale. To address this, a promising approach based on an optical fiber plasmonic sensor capable of being inserted near the electrode surface of a working battery to monitor its electrochemical kinetics without disturbing its operation is demonstrated using aqueous Zn-ion batteries as an example. The miniature and chemically inert sensor detects perturbations of surface plasmon waves propagating on its surface to rapidly screen localized electrochemical events on a sub-μm-scale thickness adjacent to the electrode interface. A stable and reproducible correlation between the real-time ion insertions over charge-discharge cycles and the optical plasmon response has been observed and quantified. This new operando measurement tool will provide crucial additional capabilities to battery monitoring methods and help guide the design of better batteries with improved electro-chemistries.

Plasmon Ag/Na-doped defective graphite carbon nitride/NiFe layered double hydroxides Z-scheme heterojunctions toward optimized photothermal-photocatalytic-Fenton performance

Abstract: Three-dimensional flower-shaped plasmon Ag/Na-doped defective graphitic carbon nitride/NiFe layered double hydroxides (Ag/NaCNN/NiFe-LDH) Z-scheme heterojunction are fabricated by hydrothermal and calcination methods. The flower-shaped structure of NiFe-LDH enhances the multiple reflection and scattering of light, providing enough active sites to improve the utilization of sunlight. The introduction of Na-doped defects narrows the band gap of graphitic carbon nitride and accelerated the charge separation. Due to the surface plasmon resonance effect of Ag, Ag/NaCNN/NiFe-LDH shows excellent photothermal effect. The synergistic effect of photothermal-photocatalytic-Fenton reaction and Z-scheme heterojunction increased the hydrogen production of Ag/NaCNN/NiFe-LDH by 0.543 mmol h −1 , which was 10 times higher than that of NiFe-LDH. The degradation efficiency of p-nitrophenol and bisphenol A under visible light was 99%. This simple strategy and reasonable design provide new ideas for the construction of Z-scheme heterojunction photocatalysts. Plasmon Ag/Na-Doped Defective Graphite Carbon Nitride/NiFe Layered Double Hydroxides Z-Scheme Heterojunctions are fabricated via simple hydrothermal and calcination methods, which exhibit excellent photothermal-photocatalytic-Fenton performance. The main reason can be ascribed to the SPR effect of Ag, Na-doped and the formation of Z-scheme heterojunction facilitates spatial charge separation. • Plasmon Ag/NaCNN/NiFe-LDH Z-scheme heterojunction is fabricated. • It shows excellent photothermal-photocatalytic-Fenton performance. • The band gap is narrowed by Na-doped defects. • It is the synergy of photocatalytic-Fenton and SPR effect. • It shows excellent H 2 production and degradation properties.

Plasmonic Nanozyme of Graphdiyne Nanowalls Wrapped Hollow Copper Sulfide Nanocubes for Rapid Bacteria‐Killing

Abstract: Plasmon stimulation represents an appealing way to modulate enzyme mimic functions, but utilization efficiency of plasmon excitation remains relatively low. To overcome this drawback, a heterojunction composite based on graphdiyne nanowalls wrapped hollow copper sulfide nanocubes (CuS@GDY) with strong localized surface plasmon resonance (LSPR) response in the near‐infrared (NIR) region is developed. This nanozyme can concurrently harvest LSPR induced hot carriers and produce photothermal effects, resulting in dramatically increased peroxidase‐like activity when exposed to 808 nm light. Both experimental results and theoretical calculations show that the remarkable catalytic performance of CuS@GDY is due to the unique hierarchical structure, narrow bandgap of GDY nanowalls, LSPR effect of CuS nanocages, fast interfacial electron transfer dynamics, and carbon vacancies on CuS@GDY. This plasmonic nanozyme exhibits rapid, efficient, broad‐spectrum antibacterial activity (>99.999%) against diverse pathogens (methicillin‐resistant Staphylococcus aureus, Staphylococcus aureus, and Escherichia coli). This study not only sheds light on the mechanism of the nanozyme‐/photocatalysis coupling process, but also opens up a new avenue for engineering plasmonic NIR light driven nanozymes for rapid synergistic photothermal and photo‐enhanced nanozyme therapy.

Chameleon-inspired multifunctional plasmonic nanoplatforms for biosensing applications

Abstract: Abstract One of the most fascinating areas in the field of smart biopolymers is biomolecule sensing. Accordingly, multifunctional biomimetic, biocompatible, and stimuli-responsive materials based on hydrogels have attracted much interest. Within this framework, the design of nanostructured materials that do not require any external energy source is beneficial for developing a platform for sensing glucose in body fluids. In this article, we report the realization and application of an innovative platform consisting of two outer layers of a nanocomposite plasmonic hydrogel plus one inner layer of electrospun mat fabricated by electrospinning, where the outer layers exploit photoinitiated free radical polymerization, obtaining a compact and stable device. Inspired by the exceptional features of chameleon skin, plasmonic silver nanocubes are embedded into a poly(N-isopropylacrylamide)-based hydrogel network to obtain enhanced thermoresponsive and antibacterial properties. The introduction of an electrospun mat creates a compatible environment for the homogeneous hydrogel coating while imparting excellent mechanical and structural properties to the final system. Chemical, morphological, and optical characterizations were performed to investigate the structure of the layers and the multifunctional platform. The synergetic effect of the nanostructured system’s photothermal responsivity and antibacterial properties was evaluated. The sensing features associated with the optical properties of silver nanocubes revealed that the proposed multifunctional system is a promising candidate for glucose-sensing applications.

Principles of surface-enhanced Raman spectroscopy

Abstract: Surface-enhanced Raman spectroscopy (SERS) has manifested its power in clinical applications, benefitted from the ability to provide fingerprint information even down to single-molecule level. In this chapter, we will guide you through the principles of SERS, including the electromagnetic field enhancement and chemical enhancement, with emphasis on the surface plasmon resonance effect. Some practical issues, such as spectral analysis and selection of SERS substrates, will also be briefed from the mechanistic understanding. The main purpose of this chapter is to provide you the necessary background to understand the literatures and start your own journey of applying SERS for clinical diagnosis.

Polarization-sensitive optoionic membranes from chiral plasmonic nanoparticles

Abstract: Optoelectronic effects differentiating absorption of right and left circularly polarized photons in thin films of chiral materials are typically prohibitively small for their direct photocurrent observation. Chiral metasurfaces increase the electronic sensitivity to circular polarization, but their out-of-plane architecture entails manufacturing and performance trade-offs. Here, we show that nanoporous thin films of chiral nanoparticles enable high sensitivity to circular polarization due to light-induced polarization-dependent ion accumulation at nanoparticle interfaces. Self-assembled multilayers of gold nanoparticles modified with L-phenylalanine generate a photocurrent under right-handed circularly polarized light as high as 2.41 times higher than under left-handed circularly polarized light. The strong plasmonic coupling between the multiple nanoparticles producing planar chiroplasmonic modes facilitates the ejection of electrons, whose entrapment at the membrane-electrolyte interface is promoted by a thick layer of enantiopure phenylalanine. Demonstrated detection of light ellipticity with equal sensitivity at all incident angles mimics phenomenological aspects of polarization vision in marine animals. The simplicity of self-assembly and sensitivity of polarization detection found in optoionic membranes opens the door to a family of miniaturized fluidic devices for chiral photonics.

New Trends in Nanoarchitectured SERS Substrates: Nanospaces, 2D Materials, and Organic Heterostructures.

Abstract: This article reviews recent fabrication methods for surface-enhanced Raman spectroscopy (SERS) substrates with a focus on advanced nanoarchitecture based on noble metals with special nanospaces (round tips, gaps, and porous spaces), nanolayered 2D materials, including hybridization with metallic nanostructures (NSs), and the contemporary repertoire of nanoarchitecturing with organic molecules. The use of SERS for multidisciplinary applications has been extensively investigated because the considerably enhanced signal intensity enables the detection of a very small number of molecules with molecular fingerprints. Nanoarchitecture strategies for the design of new NSs play a vital role in developing SERS substrates. In this review, recent achievements with respect to the special morphology of metallic NSs are discussed, and future directions are outlined for the development of available NSs with reproducible preparation and well-controlled nanoarchitecture. Nanolayered 2D materials are proposed for SERS applications as an alternative to the noble metals. The modern solutions to existing limitations for their applications are described together with the state-of-the-art in bio/environmental SERS sensing using 2D materials-based composites. To complement the existing toolbox of plasmonic inorganic NSs, hybridization with organic molecules is proposed to improve the stability of NSs and selectivity of SERS sensing by hybridizing with small or large organic molecules.

Plasmonically induced transparency in phase-coupled graphene nanoribbons

Abstract: Due to its transparent and highly dispersive nature, plasmonically induced transparency (PIT) has become an attractive field in the on-chip control of light. Conventional methods to achieve PIT are only limited to the lowest dipole-dipole or dipole-combined quadrupole modes by breaking structural symmetry. Consequently, a general methodological framework for accurately designing all-order PIT remains absent. In this paper, we propose a theoretical scheme to achieve unidirectional odd-to-even order PIT by establishing a model with two layers of periodic graphene nanoribbons. The underlying physical principles are uncovered by defining the additional resonant phase of one mode over the other as phase difference, which predicts that the PIT effects appear (disappear) generally near the positions where the phase difference is around odd (even) multiple numbers of \ensuremath{\pi}. Full-wave simulations and theoretical analysis are used to demonstrate our proposal, revealing that the proposed PIT concept possesses good robustness against both the ribbon width and the relative ribbon positions. Our results serve to provide an effective method to realize all-order PIT and to design PIT-based photonic devices.

Template-assisted self-assembly of achiral plasmonic nanoparticles into chiral structures

Abstract: Diverse templating materials and assembly strategies can be used to induce collective optical activity on achiral plasmonic building blocks. We present the advances, applications, challenges, and prospects of plasmonic–excitonic hybrids.

Collective Plasmon Coupling in Gold Nanoparticle Clusters for Highly Efficient Photothermal Therapy.

Abstract: Plasmonic nanomaterials with strong absorption at near-infrared frequencies are promising photothermal therapy agents (PTAs). The pursuit of high photothermal conversion efficiency has been the central focus of this research field. Here, we report the development of plasmonic nanoparticle clusters (PNCs) as highly efficient PTAs and provide a semiquantitative approach for calculating their resonant frequency and absorption efficiency by combining the effective medium approximation (EMA) theory and full-wave electrodynamic simulations. Guided by the theoretical prediction, we further develop a universal strategy of space-confined seeded growth to prepare various PNCs. Under optimized growth conditions, we achieve a record photothermal conversion efficiency of up to ∼84% for gold-based PNCs, which is attributed to the collective plasmon-coupling-induced near-unity absorption efficiency. We further demonstrate the extraordinary photothermal therapy performance of the optimized PNCs in in vivo application. Our work demonstrates the high feasibility and efficacy of PNCs as nanoscale PTAs.

Single-molecule optofluidic microsensor with interface whispering gallery modes

Abstract: Significance Optical microresonators have emerged as promising platforms for label-free detection of molecules. However, approaching optimum sensitivity is hindered due to the weak tail of evanescent fields. Here, we report the implementation of the interface modes for ultrasensitive sensing in a microbubble resonator. With the electromagnetic field peaked at the interface between the optical resonator and the analyte solution, interface modes enable sensing of biomolecules with a detection limit of 0.3 pg/cm2. Single-molecule detection is further demonstrated using the plasmonic-enhanced interface modes. In addition, intrinsically integrated into a microfluidic channel, the sensor exhibits ultrasmall sample consumption down to 10 pL, providing an automatic platform for biomedical analysis. Label-free sensors are highly desirable for biological analysis and early-stage disease diagnosis. Optical evanescent sensors have shown extraordinary ability in label-free detection, but their potentials have not been fully exploited because of the weak evanescent field tails at the sensing surfaces. Here, we report an ultrasensitive optofluidic biosensor with interface whispering gallery modes in a microbubble cavity. The interface modes feature both the peak of electromagnetic-field intensity at the sensing surface and high-Q factors even in a small-sized cavity, enabling a detection limit as low as 0.3 pg/cm2. The sample consumption can be pushed down to 10 pL due to the intrinsically integrated microfluidic channel. Furthermore, detection of single DNA with 8 kDa molecular weight is realized by the plasmonic-enhanced interface mode.

Operando monitoring of ion activities in aqueous batteries with plasmonic fiber-optic sensors

Abstract: Abstract Understanding ion transport kinetics and electrolyte-electrode interactions at electrode surfaces of batteries in operation is essential to determine their performance and state of health. However, it remains a challenging task to capture in real time the details of surface-localized and rapid ion transport at the microscale. To address this, a promising approach based on an optical fiber plasmonic sensor capable of being inserted near the electrode surface of a working battery to monitor its electrochemical kinetics without disturbing its operation is demonstrated using aqueous Zn-ion batteries as an example. The miniature and chemically inert sensor detects perturbations of surface plasmon waves propagating on its surface to rapidly screen localized electrochemical events on a sub-μm-scale thickness adjacent to the electrode interface. A stable and reproducible correlation between the real-time ion insertions over charge-discharge cycles and the optical plasmon response has been observed and quantified. This new operando measurement tool will provide crucial additional capabilities to battery monitoring methods and help guide the design of better batteries with improved electro-chemistries.

Spoof surface plasmon photonics

Abstract: Structuring metallic surfaces allows for the support of surface electromagnetic modes at frequencies for which they would not be allowed for smooth surfaces. These modes are called ``spoof surface plasmons'' because of their similarity to surface plasmons that are supported at optical frequencies for smooth surfaces. This article describes the physics that underlies the behavior of spoof surface plasmons and how these modes are used in applications that require the manipulation of electromagnetic fields at frequencies below optical.

Observation of localized magnetic plasmon skyrmions

Abstract: Optical skyrmions have recently been constructed by tailoring vectorial near-field distributions through the interference of multiple surface plasmon polaritons, offering promising features for advanced information processing, transport and storage. Here, we provide experimental demonstration of electromagnetic skyrmions based on magnetic localized spoof plasmons (LSP) showing large topological robustness against continuous deformations, without stringent external interference conditions. By directly measuring the spatial profile of all three vectorial magnetic fields, we reveal multiple π-twist target skyrmion configurations mapped to multi-resonant near-equidistant LSP eigenmodes. The real-space skyrmion topology is robust against deformations of the meta-structure, demonstrating flexible skyrmionic textures for arbitrary shapes. The observed magnetic LSP skyrmions pave the way to ultra-compact and robust plasmonic devices, such as flexible sensors, wearable electronics and ultra-compact antennas.