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Datta S, Vasini S, Miao X, Liu PQ. Surface-Enhanced Raman Scattering Sensors Employing a Nanoparticle-On-Liquid-Mirror (NPoLM) Architecture. SMALL METHODS 2024:e2400119. [PMID: 38639023 DOI: 10.1002/smtd.202400119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 03/26/2024] [Indexed: 04/20/2024]
Abstract
Surface-enhanced Raman scattering (SERS) sensors typically employ nanophotonic structures that support high-field confinement and enhancement in hotspots to increase the Raman scattering from target molecules by orders of magnitude. In general, high field and SERS enhancement can be achieved by reducing the critical dimensions and mode volumes of the hotspots to nanoscale. To this end, a multitude of SERS sensors employing photonic structures with nanometric hotspots have been demonstrated. However, delivering analyte molecules into nanometric hotspots is challenging, and the trade-off between field confinement/enhancement and analyte delivery efficiency is a critical limiting factor for the performance of many nanophotonic SERS sensors. Here, a new type of SERS sensor employing solid-metal nanoparticles and bulk liquid metal is demonstrated to form nanophotonic resonators with a nanoparticle-on-liquid-mirror (NPoLM) architecture, which effectively resolves this trade-off. In particular, this unconventional sensor architecture allows for the convenient formation of nanometric hotspots by introducing liquid metal after analyte molecules are efficiently delivered to the surface of gold nanoparticles. In addition, a cost-effective and reliable process is developed to produce gold nanoparticles on a substrate suitable for forming NPoLM structures. These NPoLM structures achieve two orders of magnitude higher SERS signals than the gold nanoparticles alone.
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Affiliation(s)
- Shreyan Datta
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, NY, 14260, USA
| | - Shoaib Vasini
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, NY, 14260, USA
| | - Xianglong Miao
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, NY, 14260, USA
| | - Peter Q Liu
- Department of Electrical Engineering, University at Buffalo, The State University of New York, Buffalo, NY, 14260, USA
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Gao Z, Wildenborg A, Kocoj CA, Liu E, Sheofsky C, Rawashdeh A, Qu H, Guo P, Suh JY, Yang A. Low-Loss Plasmonics with Nanostructured Potassium and Sodium-Potassium Liquid Alloys. NANO LETTERS 2023; 23:7150-7156. [PMID: 37477493 DOI: 10.1021/acs.nanolett.3c02054] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/22/2023]
Abstract
Alkali metals have low optical losses in the visible to near-infrared (NIR) compared with noble metals. However, their high reactivity prohibits the exploration of their optical properties. Recently sodium (Na) has been experimentally demonstrated as a low-loss plasmonic material. Here we report on a thermo-assisted nanoscale embossing (TANE) technique for fabricating plasmonic nanostructures from pure potassium (K) and NaK liquid alloys. We show high-quality-factor resonances from K as narrow as 15 nm in the NIR, which we attribute to the high material quality and low optical loss. We further demonstrate liquid Na-K plasmonics by exploiting the Na-K eutectic phase diagram. Our study expands the material library for alkali metal plasmonics and liquid plasmonics, potentially enabling a range of new material platforms for active metamaterials and photonic devices.
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Affiliation(s)
- Zhi Gao
- Department of Mechanical Engineering, Oakland University, Rochester, Michigan 48309, United States
| | - Aaron Wildenborg
- Department of Physics, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Conrad A Kocoj
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Energy Sciences Institute, Yale University, West Haven, Connecticut 06516, United States
| | - Eric Liu
- Department of Mechanical Engineering, Oakland University, Rochester, Michigan 48309, United States
| | - Caden Sheofsky
- Department of Physics, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Abdelsalam Rawashdeh
- Department of Mechanical Engineering, Oakland University, Rochester, Michigan 48309, United States
| | - Hongwei Qu
- Department of Electrical & Computer Engineering, Oakland University, Rochester, Michigan 48309, United States
| | - Peijun Guo
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
- Energy Sciences Institute, Yale University, West Haven, Connecticut 06516, United States
| | - Jae Yong Suh
- Department of Physics, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Ankun Yang
- Department of Mechanical Engineering, Oakland University, Rochester, Michigan 48309, United States
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