Cathodoluminescence Spectroscopy of Complex Dendritic Au Architectures for Application in Plasmon‐Mediated Photocatalysis and as SERS Substrates

Abstract

Absorption was calculated from total transmittance T(λ) and reflectance R(λ) spectra which were taken using a PerkinElmer Lambda 1050 UVvis-NIR spectrometer equipped with an integrating sphere to collect both scattered and specular reflectance and transmittance from the surface of the sample. A PMT R6872 detector for the UV/vis wavelength range and a Peltier-cooled InGaAs detector covering the 860-1800 nm range. Numerical simulations of the CL response were performed using the graphic interface (MNPBEM-GUI from Nikolaos Matthaiakakis of the MNPBEM toolbox. [44] Their optical properties were taken from the Johnson and Christy tabulated data, [53] while an electron beam excitation that mimics the experimental conditions was set, having an energy of 15 keV and a finite width of 1 nm, impinging orthogonally at the tip of the Au triangle. SERS measurements of methylene blue (from Sigma-Aldrich) were carried out using a Renishaw InVia Reflex spectrometer equipped with a 633 nm laser at a power of 0.33 mW and a 1200 l mm −1 grating. The samples were immersed overnight in a 5 ppm MB solution in ethanol, and gently rinsed with water before and let dry naturally before starting the SERS measurements. All the SERS measurements were performed at room-temperature in standard atmosphere with an acquisition time of 1 s and two accumulations for noise reduction. The SERS measurements were acquired with a 5× objective producing a spot size of ≈8 µm.

3D Nanoporous Metallic Networks for SERS-Based Detection of Water Contaminants

“…Compared to the network grown onto silica aerogel, the observed values are comparable, yet a bit lower. Because of high nonlinear efficiencies, such a 3d structure has the potential to function as a disordered SHG reflector substrate for vast applications, among them SERS and coherent anti-Stokes Raman scattering (CARS). − …”

Ab initio investigation of hot electron transfer in CO2 plasmonic photocatalysis in the presence of hydroxyl adsorbate

“…3(a)), thus emphasizing the critical role of spectral overlap in efficiently modulating electron transfer processes. 81,82 Furthermore, below B2 eV, photoabsorption decreases, thus resulting in a negligible generation of HEs within the molecule.…”

Plasmon-induced hot carrier dynamics and utilization

“…For instance, Fusco et al synthesized different dendritic Au architectures by varying electrodeposition time. Using the degeneration rate of methylene blue (MB) to measure the photocatalytic activity, they found that the sample with the lowest SERS intensity exhibits the highest photocatalytic efficiency [193] . Experimentally, the enhanced photochemical processes have been determined in hot spots of plasmonic nanostructures [194,195] , corroborating the theoretical results.…”