Vibrational Strong Coupling with Surface Plasmons and the Presence of Surface Plasmon Stop Bands (article)

This is the final version. Available on open access from American Chemical Society via the DOI in this recordThe datasets associated with this article are available in ORE at https://doi.org/10.24378/exe.1604We demonstrate strong coupling between surface plasmon resonances and molecular vibrational resonances of poly(methyl methacrylate) (PMMA) molecules in the mid-infrared range through the use of grating coupling, complimenting earlier work using microcavities and localized plasmon resonances. We choose the period of the grating so that we may observe strong coupling between the surface plasmon mode associated with a patterned gold film and the C=O vibrational resonance in an overlying polymer film. We present results from experiments and numerical simulations to show that surface plasmon modes provide convenient open cavities for vibrational strong coupling experiments. In addition to providing momentum matching between surface plasmon modes and incident light, gratings may also produce a modification of the surface plasmon properties, notably their dispersion. We further show that for the parameters used in our experiment surface plasmon stop bands are formed, and we find that both stop-band edges undergo strong coupling.Engineering and Physical Sciences Research Council (EPSRC)European Research Council (ERC

Polariton assisted photoemission from a layered molecular material: Role of vibrational states and molecular absorption (article)

This is the final version. Available on open access from the Royal Society of Chemistry via the DOI in this recordThe dataset associated with this article is available in ORE at: https://doi.org/10.24378/exe.3483The way molecules absorb, transfer, and emit light can be modified by coupling them to optical cavities. The extent of the modification is often defined by the cavity–molecule coupling strength, which depends on the number of coupled molecules. We experimentally and numerically study the evolution of photoemission from a thin layered J-aggregated molecular material strongly coupled to a Fabry–Perot microcavity as a function of the number of coupled layers. We unveil an important difference between the strong coupling signatures obtained from reflection spectroscopy and from polariton assisted photoluminescence. We also study the effect of the vibrational modes supported by the molecular material on the polariton assisted emission both for a focused laser beam and for normally incident excitation, for two different excitation wavelengths: a laser in resonance with the lower polariton branch, and a laser not in resonance. We found that Raman scattered photons appear to play an important role in populating the lower polariton branch, especially when the system was excited with a laser in resonance with the lower polariton branch. We also found that the polariton assisted photoemission depends on the extent of modification of the molecular absorption induced by the molecule–cavity coupling.Leverhulme TrustEuropean Research Council (ERC

Polariton assisted photoemission from a layered molecular material: Role of vibrational states and molecular absorption (dataset)

This is the dataset used for the Vasista et al. (2021) article "Polariton assisted photoemission from a layered molecular material: Role of vibrational states and molecular absorption" published in Nanoscale.The article associated with this dataset is available in ORE at: http://hdl.handle.net/10871/126718The way molecules absorb, transfer, and emit light can be modified by coupling them to optical cavities. The extent of the modification is often defined by the cavity-molecule coupling strength, which depends on the number of coupled molecules. We experimentally and numerically study the evolution of photoemission from a thin layered J-aggregated molecular material strongly coupled to a Fabry-Perot microcavity as a function of the number of coupled layers. We unveil an important difference between the strong coupling signatures obtained from reflection spectroscopy and from polariton assisted photoluminescence. We also study the effect of the vibrational modes supported by the molecular material on the polariton assisted emission both for a focused laser beam and for normally incident excitation, for two different excitation wavelengths: a laser in resonance with the lower polariton branch, and a laser not in resonance. We found that Raman scattered photons appear to play an important role in populating the lower polariton branch, especially when the system was excited with a laser in resonance with the lower polariton branch. We also found that the polariton assisted photoemission depends on the extent of modification of the molecular absorption induced by the molecule-cavity coupling.Leverhulme TrustEuropean Research Council (ERC

Cavity-Free Ultrastrong Light-Matter Coupling (dataset)

Figure data in .txt form. Some large datasets were generated using scripts in MATLAB; these scripts were included alongside the .fig files.This is the dataset used for the Thomas et al. (2021) article "Cavity-Free Ultrastrong Light-Matter Coupling" published in The Journal of Physical Chemistry Letters.Leverhulme TrustEuropean Research Council (ERC

All-optical control of phase singularities using strong light-matter coupling (dataset)

Data for figures. Calculated figures are stored in MATLAB .fig format.This is the dataset used for the Thomas et al. (2022) article "All-optical control of phase singularities using strong light-matter coupling".European CommissionLeverhulme Trus

Vibrational strong coupling with surface plasmons and the presence of surface plasmon stop bands (dataset)

Data associated with the figures in the Menghrajani et al. (2019) article "Vibrational strong coupling with surface plasmons and the presence of surface plasmon stop bands" published in ACS Photonics.The article associated with these datasets is available in ORE at: http://hdl.handle.net/10871/38669We demonstrate strong coupling between surface plasmon resonances and molecular vibrational resonances of polymethyl methacrylate (PMMA) molecules in the mid-infrared range through the use of grating coupling, complimenting earlier work using microcavities and localised plasmon resonances. We choose the period of the grating so that we may observe strong coupling between the surface plasmon mode associated with a patterned gold film and the C=O vibrational resonance in an overlying polymer film. We present results from experiments and numerical simulations to show that surface plasmon modes provide convenient open cavities for vibrational strong coupling experiments. In addition to providing momentum matching between surface plasmon modes and incident light, gratings may also produce a modification of the surface plasmon properties, notably their dispersion. We further show that for the parameters used in our experiment, surface plasmon stop bands are formed, and we find that both stop-band edges undergo strong coupling.Engineering and Physical Sciences Research Council (EPSRC)European Research Council (ERC

Design of reaction-driven active configuration for enhanced CO2 electroreduction

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordData Availability: Data will be made available on request.Metal-nitrogen-carbon single-atom catalysts (SACs) have emerged as promising candidates for electrocatalytic CO2 reduction reaction. However, the perpendicular dz2 orbital within planar metal site mainly interacts with *COOH, resulting in inferior CO2 activation. Inspired by reaction-driven active configuration, here we propose to upshift nickel single-atom away from nitrogen-carbon substrate, prominently promoting the interaction between CO2 and other d orbitals besides dz2 . Theoretical and experimental analyses reveal that upshifting nickel site away substrate induces dxz, dyz, and dz2 to hybridize with CO2, expediting CO2 conversion to *COOH. The planar and out-of-plane Ni-N sites are formed on carbon nanosheet (Ni1-N/CNS) and curved nanoparticle (Ni1-N/CNP), respectively, which is verified by X-ray absorption fine structure spectroscopy. Impressively, the Ni1-N/CNP presents CO Faradaic efficiency of 96.4 % at 500 mA cm− 2 and energy conversion efficiency of 79.8 % in flow cell, outperforming Ni1-N/CNS and most SACs. This work highlights the simulation of reaction-driven active sites for efficient electrocatalysis.Natural Science Foundation of ChinaInternational Science and Technology CooperationGuangdong Basic and Applied Basic Research FoundationMinistry of Science and Technology, TaiwanEngineering and Physical Sciences Research Council (EPSRC