Nano-Raman Scattering Microscopy: Resolution and Enhancement

Kawata, Satoshi; Ichimura, Taro; Taguchi, Akihito; Kumamoto, Yoshiaki

doi:10.1021/acs.chemrev.6b00560

Cited by 99 publications

(50 citation statements)

References 236 publications

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“…By constructing plasmonic systems in the nanometer scale we are, effectively, employing antennas that couple strongly with electromagnetic radiation at frequencies up to the UV spectral range 1 and localize its radiant energy. In doing so we can manipulate the propagation of light at this scale and create novel optical effects, [2][3][4][5][6] enhance secondary such as Raman scattering 7,8 or efficiently promote the conversion of light into other forms of energy. [9][10][11] Among the topics where the use of plasmonic nanoparticles has extended our scientific purview has been the study of optical chirality.…”

Section: Introductionmentioning

confidence: 99%

Chiral Plasmonic Nanocrystals for Generation of Hot Electrons: Toward Polarization-Sensitive Photochemistry

et al. 2019

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The use of biomaterials -with techniques such as DNA-directed assembly or biodirected synthesis -can surpass top-down fabrication techniques in creating plasmonic superstructures, in terms of spatial resolution, range of functionality and fabrication speed.Particularly, by enabling a very precise placement of nanoparticles in a bio-assembled complex or a controlled bio-directed shaping of single nanoparticles, plasmonic nanocrystals can show remarkably strong circular dichroism (CD) signals. Here we show that chiral bio-plasmonic assemblies can enable polarization-sensitive photochemistry based on the generation of energetic (hot) electrons. It is now established that hot plasmonic electrons can induce surface photochemistry or even reshape plasmonic nanocrystals. Here we show that merging chiral plasmonic nanocrystal systems and the hot-election generation effect offers unique possibilities in photochemistry -such as polarization-sensitive photochemistry promoting nonchiral molecular reactions, chiral photo-induced growth of a colloid at the atomic level and chiral photochemical destruction of chiral nanocrystals. In contrast, for chiral molecular systems the equivalent of the described effects is challenging to be observed because molecular species exhibit typically very small CD signals. Moreover, we compare our findings with traditional chiral photochemistry at the molecular level, identifying new, different regimes for chiral photochemistry with possibilities that are unique for plasmonic colloidal systems. In this study, we bring together the concept of hot-electron generation and the field of chiral colloidal plasmonics. Using chiral plasmonic nanorod complexes as a model system, we demonstrate remarkably strong CD in both optical extinction and generation rates of hot electrons. Studying the regime of steady-state excitation, we discuss the influence of geometrical and material parameters on the chiral effects involved in the generation of hot electrons. Optical chirality and the chiral hot-electron response in the nanorod dimers result from complex inter-particle interactions, which can appear in the weak coupling 3 regime or in the form of Rabi splitting. Regarding practical applications, our study suggests interesting opportunities in polarization-sensitive photochemistry, chiral recognition or separation, and in promoting chiral crystal growth at the nanoscale.

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Section: Introductionmentioning

confidence: 99%

Chiral Plasmonic Nanocrystals for Generation of Hot Electrons: Toward Polarization-Sensitive Photochemistry

et al. 2019

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“…[6][7][8] The plasmon resonance simulated is then linked to the expected Raman response, although several theories and other factors also come into play. [9][10][11] Unfortunately, tremendous computational capacity and calculation time are generally unavoidable when it comes to predicting the specific behavior of plasmonic substrates. In fact, the challenge is almost as old as the field itself.…”

mentioning

confidence: 99%

Plasmon response evaluation based on image-derived arbitrary nanostructures

et al. 2018

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The optical response of realistic 3D plasmonic substrates composed of randomly shaped particles of different size and interparticle distance distributions in addition to nanometer scale surface roughness is intrinsically challenging to simulate due to computational limitations. Here, we present a Finite Element Method (FEM)-based methodology that bridges in-depth theoretical investigations and experimental optical response of plasmonic substrates composed of such silver nanoparticles. Parametrized scanning electron microscopy (SEM) images of surface enhanced Raman spectroscopy (SERS) active substrate and tip-enhanced Raman spectroscopy (TERS) probes are used to simulate the far-and near-field optical response. Far-field calculations are consistent with experimental dark field spectra and charge distribution images reveal for the first time in arbitrary structures the contributions of interparticle hybridized modes such as sub-radiant and super-radiant modes that also locally organize as basic units for Fano resonances. Near-field simulations expose the spatial position-dependent impact of hybridization on field enhancement. Simulations of representative sections of TERS tips are shown to exhibit the same unexpected coupling modes. Near-field simulations suggest that these modes can contribute up to 50% of the amplitude of the plasmon resonance at the tip apex but, interestingly, have a small effect on its frequency in the visible range. The band position is shown to be extremely sensitive to particle nanoscale roughness, highlighting the necessity to preserve detailed information at both the largest and the smallest scales. To the best of our knowledge, no currently available method enables reaching such a detailed description of large scale realistic 3D plasmonic systems.

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“…[92] However, if the dimension of the tip is related to an effective incident wavelength, antenna resonances can be formed, similar to the excitation of surface plasmon. [93,94] In this case, these three enhancement mechanisms all contribute, and the highest field enhancement is expected.…”

Section: Tip Enhancementmentioning

confidence: 85%

Tip-enhanced Raman spectroscopy: principles, practice, and applications to nanospectroscopic imaging of 2D materials

2018

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Two-dimensional (2D) materials have been one of the most extensively studied classes of modern materials, due to their astonishing chemical, optical, electronic, and mechanical properties, which are different from their bulk counterparts. The edges, grain boundaries, local strain, chemical bonding, molecular orientation, and the presence of nanodefects in these 2D monolayers (MLs) will strongly affect their properties. Currently, it is still challenging to investigate such atomically thin 2D monolayers with nanoscale spatial resolution, especially in a label-free and non-destructive way. Tip-enhanced Raman spectroscopy (TERS), which combines the merits of both scanning probe microscopy (SPM) and Raman spectroscopy, has become a powerful analytical technique for studying 2D monolayers, because it allows very high-resolution and high-sensitivity local spectroscopic investigation and imaging, and also provides rich chemical information. This review provides a summary of methods to study 2D monolayers and an overview of TERS, followed by an introduction to the current state-of-the-art and theoretical understanding the spatial resolution in TERS experiments. Surface selection rules are also discussed. We then focus on the capabilities and potential of TERS for nanoscale chemical imaging of 2D materials, such as graphene, transition metal dichalcogenides (TMDCs), and 2D polymers. We predict that TERS will become widely accepted and used as a versatile imaging tool for chemical investigation of 2D materials at the nanoscale.

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Nano-Raman Scattering Microscopy: Resolution and Enhancement

Cited by 99 publications

References 236 publications

Chiral Plasmonic Nanocrystals for Generation of Hot Electrons: Toward Polarization-Sensitive Photochemistry

Chiral Plasmonic Nanocrystals for Generation of Hot Electrons: Toward Polarization-Sensitive Photochemistry

Plasmon response evaluation based on image-derived arbitrary nanostructures

Tip-enhanced Raman spectroscopy: principles, practice, and applications to nanospectroscopic imaging of 2D materials

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