We performed cathodoluminescence (CL) spectroscopy and imaging in a high-resolution scanning electron microscope to locally and selectively excite and investigate the plasmonic properties of a multi-branched gold nanostar on a silicon substrate. This method allows us to map the local density of optical states from the nanostar with a spatial resolution down to a few nanometers. We resolve, both in the spatial and spectral domain, different plasmon modes associated with the nanostar. Finite-difference time-domain (FDTD) numerical simulations are performed to support the experimental observations. We investigate the effect of the substrate on the plasmonic properties of these complex-shaped nanostars. The powerful CL-FDTD combination helps us to understand the effect of the substrate on the plasmonic response of branched nanoparticles.
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http://dx.doi.org/10.1088/0957-4484/24/40/405704 | DOI Listing |
Langmuir
January 2025
Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe, Mizuho, Nagoya 467-8603, Aichi, Japan.
In this study, we demonstrate a novel and efficient fabrication methodology for nonclose-packed, two-dimensional (2D) colloidal crystals exhibiting square lattice structures. In our recent work, we detailed the formation of 2D colloidal crystals via the electrostatic adsorption of three-dimensional (3D) charged colloidal crystals onto oppositely charged substrates. These 3D colloidal crystals possessed a face-centered cubic (FCC) lattice structure with their (111) planes aligned parallel to the substrate, facilitating the formation of 2D crystals with triangular lattice arrangements upon adsorption.
View Article and Find Full Text PDFBiotechnol Rep (Amst)
March 2025
Department of Biology, University of York, Wentworth Way, York, YO10 5DD, UK.
Unlabelled: Ongoing research in biosensor technologies has led to advanced functional materials for healthcare diagnostics, and bacteriophages (phages), demonstrating exceptional utility due to their high specificity, accuracy, rapid, label-free, and wireless detection capabilities with minimal false-positive results. Phage-based-pathogen-detecting biosensors (PBPDBs) include surface plasmon resonance (SPR) biosensors, magnetoelastic (ME), electrochemical, and quartz crystal microbalance (QCM) biosensors. Commonly used substrates for PBPDBs are gold, silicon, glass, carbon-based materials, magnetic particles, and quantum dots.
View Article and Find Full Text PDFNano Lett
January 2025
Facultad de Ciencias Exactas y Naturales, Departamento de Física, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina.
Nanostructured high-index dielectrics have shown great promise as low-loss photonic platforms for wavefront control and enhancing optical nonlinearities. However, their potential as optomechanical resonators has remained unexplored. In this work, we investigate the generation and detection of coherent acoustic phonons in individual crystalline gallium phosphide nanodisks on silica in a pump-probe configuration.
View Article and Find Full Text PDFSoft Matter
January 2025
Faculty of Chemistry, Ho Chi Minh City University of Science, Vietnam National University, Ho Chi Minh City, 227 Nguyen Van Cu Street, Ward 4, District 5, Ho Chi Minh City 70000, Vietnam.
Surface-enhanced Raman spectroscopy (SERS) is a highly sensitive analytical technique with excellent molecular specificity. However, separate pristine nanoparticles produce relatively weak Raman signals. It is necessary to focus on increasing the "hot-spot" density generated at the nanogaps between the adjacent nanoparticles (second-generation SERS hotspot), thus significantly boosting the Raman signal by creating an electromagnetic field.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Hainan Engineering Research Center of Tropical Ocean Advanced Opto-Electrical Functional Materials, College of Chemistry and Chemical Engineering, Hainan Normal University, Haikou 571158, China.
Chrysoidin (CG) can be ingested into the human body through the skin and cause chronic toxicity, so the detection of CG levels in the environment is crucial. In this study, we synthesize F-Ag@ZIF-8/PVC molecular-imprinted membranes (FZAP-MIM) by an innovative combination of SERS detection, membrane separation, and a molecular-imprinted technique in order to perform the analysis of CG in water. The plasmonic MOF material as a SERS substrate helps to enrich the target and realize the spatial overlap of the target with the nanoparticle tip "hotspot".
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