Manipulating Light–Matter Interactions in Plasmonic Nanoparticle Lattices

Nisika

Advanced Optical Materials

2020

years, great advances have been made to grow various shaped semiconductor nanocrystals (SNCs) like quantum dots, [7] nanowires, [8] nanorods (NR), [9] and other advanced shaped nanostructures, [10-12] with great precision. However, these semiconductor nanostructures have small extinction cross-sections (even smaller than geometric cross-section), leading to limited absorbance and emission quantum yields. This hinders the progress of semiconductor nanostructures in several areas ranging from clean energy production to various sensing applications. Among many promising solutions, integrating plasmonic nanoparticles (PNPs) with semiconductor nanostructures emerges as the most prominent way to alleviate aforementioned issue. The PNPs have greater extinction cross-section than SNCs (even greater than geometric cross-section), owing to light absorption and scattering by collective and coherent electron oscillations. [13,14] Moreover, these coherent oscillations can couple with electromagnetic wavelengths far greater than particle size, enabling them to guide light to subwavelength scales, thus overcoming diffraction limit. [15] Besides this, proper control over size and shape of plasmonic nanostructures enables engineering of their intrinsic properties to meet the criteria of required application. [16] For instance, by changing the aspect ratio (length to diameter ratio) of nanorods, one can cover wide spectral regions ranging from visible to near-infrared (NIR) regimes. [17] Thus, the integration of plasmonic and semiconductor nanostructures to obtain greater extinction cross-sections and modified properties in these hybrid nanostructures has received great attention from the research community over the past years. The properties of these hybrid nanostructures can be very different from the two nanoconstituents (metal and semiconductor nanostructures), owing to plasmon-exciton interactions. [18-20] Various configurations of metal/semiconductor nanostructures have been synthesized like metallic core/semiconductor shell, [21] semiconductor NR/metal nanoparticles (MNPs), [22] Janus metal/ semiconductor nanostructures, [23] and many others have been reported, [24-26] with varying absorption and emissive properties, targeting high performance applications. The energy transfer between metal-semiconductor nanostructures resulting from integration of PNPs and SNCs Hybrid nanostructures composed of metal and semiconducting nanocrystals have drawn tremendous attention owing to their extraordinary absorption and emission properties. The energy transfer in metal-semiconductor hybrids as a result of synergetic plasmon-exciton interactions leads to numerous applications in the field of solar energy harvesting, photocatalytic reactions, imaging, photonics, sensing, and many more. Various breakthroughs in advanced characterization techniques over the past decade have disclosed several factors affecting the energy transfer processes leading to modified absorption and emission properties in metal-semiconductor hybrids. Herein, various ...

Section: Piretmentioning

confidence: 85%

“…It has been validated from various studies that plasmonic nanomaterials can induce strong electric fields in their near‐field (field enhancement up to thousands of times), increasing absorption of SNCs. [ 31,197,198 ]…”

Section: Intrinsic Properties Of Metal–semiconductor Heterostructuresmentioning

confidence: 99%

Modified Absorption and Emission Properties Leading to Intriguing Applications in Plasmonic–Excitonic Nanostructures

Nisika

Advanced Optical Materials

2020

“…For another 2D SERS-active nanomaterials, boron nitride is a single atom honeycomb layered structure with a graphite-like structure. This is a wide bandgap semiconductor with excellent electrical and magnetic properties; [87] this materials is also chemically inert but another potential SERS substrate. For instance, liu et al [88] combined hexagonal boron nitride nanosheets (h-BNNS) with insoluble copper phthalocyanine (CuPc) and a Figure 3.…”

Section: D Nanostructuresmentioning

confidence: 99%

Dimensional Surface‐Enhanced Raman Scattering Nanostructures for MicroRNA Profiling

Li¹,

Li²,

Qu³

et al. 2021

Small Structures

Surface-enhanced Raman scattering (SERS) spectrum is an ultrasensitive quantitative tool for molecular fingerprinting and is very suitable for the analyzing and detecting trace substances, including low-abundance miRNAs. Researchers have already investigated the effects of nanomaterial-based SERS profiling on miRNA. As review herein, these SERS-active nanostructures can be generally classified into 0D, 1D, 2D, and 3D nanostructures according to their distinct structure. These SERS-active structures with differential structural dimensions exhibit differences in terms of detection performance which can be attributed to the unique nanomaterials involved and the overall design of the SERS nanostructures. In this review the authors focus on the design of SERS nanostructures in previous research, the advantages and disadvantages in miRNA profiling of the different dimensional nanostructures are analyzed, and some design principles to develop guidelines, to fabricate more effective SERS nano-sensors with ultra-high sensitivity and high levels accuracy are summarized, thereby promoting the practical application of miRNA profiling by SERS technology in complex life systems.

Advanced Optical Materials

“…The collective lattice resonance stemming from the diffractive coupling in a periodic array of either metal [ 10–12 ] or high‐index dielectric nanoparticles [ 13 ] requires a symmetric refractive‐index environment between the bottom substrate and the upper cladding (e.g., aqueous buffers in sensing). [ 14–17 ] An asymmetric environment can inhibit long‐range coupling between nanoparticles and suppress lattice resonances.…”

Section: Figurementioning

confidence: 99%

Low‐Index‐Contrast Dielectric Lattices on Metal for Refractometric Sensing

Dong

Chen

Huang

et al. 2020

In this context, metal nanostructures with localized surface plasmon resonances (LSPRs) have attracted extensive attention. [2] LSPRs can be excited with wide-field normal-incidence illumination, and the optical setup for sensing can be simply constructed based on standard optical microscopes. [3] Periodic plasmonic nanostructures can offer additional advantages, [4] for example, a much narrower resonance linewidth (compared to LSPRs) that is beneficial for measuring a small spectral shift. However, the intense optical fields on the surface of plasmonic nanostructures can result in dissipative loss and lead to heating. Recently, periodic arrays of high-index dielectric nanostructures with collective resonances have been proposed as an alternative. [5-9] However, for periodic arrays of high-index dielectric nanostructures, even with broken inplane symmetry (so-called quasi-BIC; bound states in the continuum), [7,8] the bulk sensitivity (defined as the spectral shift upon the change in the bulk refractive index of the surrounding environment) is much lower than that of plasmonic arrays with the same lattice spacing. The collective lattice resonance stemming from the diffractive coupling in a periodic array of either metal [10-12] or high-index dielectric nanoparticles [13] requires a symmetric refractive-index environment between the bottom substrate and the upper cladding (e.g., aqueous buffers in sensing). [14-17] An asymmetric environment can inhibit long-range coupling between nanoparticles and suppress lattice resonances. In optical sensing, a periodic array of either metal or high-index dielectric nanoparticles is usually fabricated on a transparent substrate and exposed to solutions with different refractive indices. The index-mismatch between widely used quartz substrates (n ≈ 1.5) and aqueous buffers (n ≈ 1.33) can broaden the resonances and deteriorate the bulk sensitivity. [18] Although for sensing in aqueous buffers, one can find fluoropolymer (Cytop) with refractive index close to water to create a symmetric environment, [18,19] it is highly desirable to have a platform that can maintain high-quality resonances when subjected to a relatively large change in the bulk refractive index. (A symmetric refractive-index environment may not be required in a periodic structure with high-quality resonances of quasi-BIC type, for which the bulk sensitivity, however, is not high in the published literature. [7,8]) We recently reported that a hybrid system composed of low-index dielectric pillar arrays on a metal film can support This article reports refractometric sensing using two optical resonances of different types supported by TiO 2 nanopillar arrays on a gold film, which can be exposed to aqueous or organic environments. One lattice resonance, with enhanced electric fields extending into the surrounding environment, can maintain a quality factor Q > 200 when the bulk refractive index of the surrounding environment varies in a large range from 1.33 to 1.58. This lattice resonance exhibits not only sharp trans...