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- Hakonen, Aron, 1970, et al.
(författare)
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Detection of nerve gases using surface-enhanced Raman scattering substrates with high droplet adhesion
- 2016
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 8:3, s. 1305-1308
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Tidskriftsartikel (refereegranskat)abstract
- Threats from chemical warfare agents, commonly known as nerve gases, constitute a serious security issue of increasing global concern because of surging terrorist activity worldwide. However, nerve gases are difficult to detect using current analytical tools and outside dedicated laboratories. Here we demonstrate that surface-enhanced Raman scattering (SERS) can be used for sensitive detection of femtomol quantities of two nerve gases, VX and Tabun, using a handheld Raman device and SERS substrates consisting of flexible gold-covered Si nanopillars. The substrate surface exhibits high droplet adhesion and nanopillar clustering due to elasto-capillary forces, resulting in enrichment of target molecules in plasmonic hot-spots with high Raman enhancement. The results may pave the way for strategic life-saving SERS detection of chemical warfare agents in the field.
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| 2. |
- Ogier, Robin, 1987, et al.
(författare)
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Continuous-Gradient Plasmonic Nanostructures Fabricated by Evaporation on a Partially Exposed Rotating Substrate
- 2016
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 28:23, s. 4658-4664
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Tidskriftsartikel (refereegranskat)abstract
- Evaporation on a partially exposed rotating substrate (PERS) was used to generate continuous and precise gradients in nanoscale structure parameters. All materials (gold, chromium, alumina, and silver) were deposited in an electron beam evaporation system with stage rotation and tilt possibilities. All evaporations were performed at a high vacuum. To fabricate nanostructures on a glass substrates by HCL, the substrate was first spin-coated with a layer of 950 PMMA and wetted with a poly(diallyldimethylammonium chloride) (PDDA) solution. Negatively charged PS beads were then drop casted and self-assembled on the surface. A thin layer of metal (gold or chromium) was evaporated to act as a mask. The beads were removed by tape stripping, resulting in a mask with holes arranged in a pattern determined by the colloidal particles. The PMMA situated underneath the holes in the film was removed by oxygen plasma etching. Due to the continuous characteristic of the gradients, high precision in the geometric parameters of fabricated nanostructures can be achieved.
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| 6. |
- Verre, Ruggero, 1985, et al.
(författare)
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Directional Light Extinction and Emission in a Metasurface of Tilted Plasmonic Nanopillars
- 2016
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 16:1, s. 98-104
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Tidskriftsartikel (refereegranskat)abstract
- Plasmonic optical antennas and metamaterials with an ability to boost light-matter interactions for particular incidence or emission angles could find widespread use in solar harvesting, biophotonics, and in improving photon source performance at optical frequencies. However, directional plasmonic structures have generally large footprints or require complicated geometries and costly nano-fabrication technologies. Here, we present a directional metasurface realized by breaking the out-of-plane symmetry of its individual elements: tilted subwavelength plasmonic gold nanopillars. Directionality is caused by the complex charge oscillation induced in each individual nanopillar, which essentially acts as a tilted dipole above a dielectric interface. The metasurface is homogeneous over a macroscopic area and it is fabricated by a combination of facile colloidal lithography and off-normal metal deposition. Fluorescence excitation and emission from dye molecules deposited on the metasurface is enhanced in specific directions determined by the tilt angle of the nanopillars. We envisage that these directional metasurfaces can be used as cost-effective substrates for surface-enhanced spectroscopies and a variety of nanophotonic applications.
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