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Hybrid plasmonic nanostructures for enhanced single-molecule detection sensitivity

Herkert, Ediz Kaan, Bermeo Alvaro, Domenica Romina, Recchia, Martina, Langbein, Wolfgang ORCID:, Borri, Paola ORCID: and Garcia-Parajo, Maria F. 2023. Hybrid plasmonic nanostructures for enhanced single-molecule detection sensitivity. ACS Nano 17 (9) , pp. 8453-8464. 10.1021/acsnano.3c00576

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Biosensing applications based on fluorescence detection often require single-molecule sensitivity in the presence of strong background signals. Plasmonic nanoantennas are particularly suitable for these tasks, as they can confine and enhance light in volumes far below the diffraction limit. The recently introduced antenna-in-box (AiB) platforms achieved high single-molecule detection sensitivity at high fluorophore concentrations by placing gold nanoantennas in a gold aperture. However, hybrid AiB platforms with alternative aperture materials such as aluminum promise superior performance by providing better background screening. Here, we report on the fabrication and optical characterization of hybrid AiBs made of gold and aluminum for enhanced single-molecule detection sensitivity. We computationally optimize the optical properties of AiBs by controlling their geometry and materials and find that hybrid nanostructures not only improve signal-to-background ratios but also provide additional excitation intensity and fluorescence enhancements. We further establish a two-step electron beam lithography process to fabricate hybrid material AiB arrays with high reproducibility and experimentally validate the higher excitation and emission enhancements of the hybrid nanostructures as compared to their gold counterpart. We foresee that biosensors based on hybrid AiBs will provide improved sensitivity beyond the capabilities of current nanophotonic sensors for a plethora of biosensing applications ranging from multicolor fluorescence detection to label-free vibrational spectroscopy.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Biosciences
Publisher: American Chemical Society
ISSN: 1936-0851
Date of First Compliant Deposit: 24 April 2023
Date of Acceptance: 28 March 2023
Last Modified: 20 Jun 2023 17:03

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