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Zhou J, Barnard E, Cabrini S, Munechika K, Schwartzberg A, Weber-Bargioni A. Integrating collapsible plasmonic gaps on near-field probes for polarization-resolved mapping of plasmon-enhanced emission in 2D material. OPTICS EXPRESS 2023; 31:20440-20448. [PMID: 37381438 DOI: 10.1364/oe.490112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 05/16/2023] [Indexed: 06/30/2023]
Abstract
Scanning near-field optical microscopy (SNOM) is an important technique used to study the optical properties of material systems at the nanoscale. In previous work, we reported on the use of nanoimprinting to improve the reproducibility and throughput of near-field probes including complicated optical antenna structures such as the 'campanile' probe. However, precise control over the plasmonic gap size, which determines the near-field enhancement and spatial resolution, remains a challenge. Here, we present a novel approach to fabricating a sub-20 nm plasmonic gap in a near-field plasmonic probe through the controlled collapse of imprinted nanostructures using atomic layer deposition (ALD) coatings to define the gap width. The resulting ultranarrow gap at the apex of the probe provides a strong polarization-sensitive near-field optical response, which results in an enhancement of the optical transmission in a broad wavelength range from 620 to 820 nm, enabling tip-enhanced photoluminescence (TEPL) mapping of 2-dimensional (2D) materials. We demonstrate the potential of this near-field probe by mapping a 2D exciton coupled to a linearly polarized plasmonic resonance with below 30 nm spatial resolution. This work proposes a novel approach for integrating a plasmonic antenna at the apex of the near-field probe, paving the way for the fundamental study of light-matter interactions at the nanoscale.
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2
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Ou TH, Hu P, Liu Z, Wang Y, Hossain S, Meng D, Shi Y, Zhang S, Zhang B, Song B, Liu F, Cronin SB, Wu W. Plasmon-Enhanced Photocatalytic CO 2 Reduction for Higher-Order Hydrocarbon Generation Using Plasmonic Nano-Finger Arrays. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:nano13111753. [PMID: 37299656 DOI: 10.3390/nano13111753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/18/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023]
Abstract
The carbon dioxide reduction reaction (CO2RR) is a promising method to both reduce greenhouse gas carbon dioxide (CO2) concentrations and provide an alternative to fossil fuel by converting water and CO2 into high-energy-density chemicals. Nevertheless, the CO2RR suffers from high chemical reaction barriers and low selectivity. Here we demonstrate that 4 nm gap plasmonic nano-finger arrays provide a reliable and repeatable plasmon-resonant photocatalyst for multiple-electrons reactions: the CO2RR to generate higher-order hydrocarbons. Electromagnetics simulation shows that hot spots with 10,000 light intensity enhancement can be achieved using nano-gap fingers under a resonant wavelength of 638 nm. From cryogenic 1H-NMR spectra, formic acid and acetic acid productions are observed with a nano-fingers array sample. After 1 h laser irradiation, we only observe the generation of formic acid in the liquid solution. While increasing the laser irradiation period, we observe both formic and acetic acid in the liquid solution. We also observe that laser irradiation at different wavelengths significantly affected the generation of formic acid and acetic acid. The ratio, 2.29, of the product concentration generated at the resonant wavelength 638 nm and the non-resonant wavelength 405 nm is close to the ratio, 4.93, of the generated hot electrons inside the TiO2 layer at different wavelengths from the electromagnetics simulation. This shows that product generation is related to the strength of localized electric fields.
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Affiliation(s)
- Tse-Hsien Ou
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Pan Hu
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Zerui Liu
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Yunxiang Wang
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Sushmit Hossain
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Deming Meng
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Yudi Shi
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Sonia Zhang
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Boxin Zhang
- Mork Family Department of Chemical Engineering and Material Science, University of Southern California, Los Angeles, CA 90089, USA
| | - Boxiang Song
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Fanxin Liu
- Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, China
| | - Stephen B Cronin
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Wei Wu
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
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3
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An T, Wen J, Dong Z, Zhang Y, Zhang J, Qin F, Wang Y, Zhao X. Plasmonic Biosensors with Nanostructure for Healthcare Monitoring and Diseases Diagnosis. SENSORS (BASEL, SWITZERLAND) 2022; 23:445. [PMID: 36617043 PMCID: PMC9824517 DOI: 10.3390/s23010445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/20/2022] [Accepted: 12/20/2022] [Indexed: 06/17/2023]
Abstract
Nanophotonics has been widely utilized in enhanced molecularspectroscopy or mediated chemical reaction, which has major applications in the field of enhancing sensing and enables opportunities in developing healthcare monitoring. This review presents an updated overview of the recent exciting advances of plasmonic biosensors in the healthcare area. Manufacturing, enhancements and applications of plasmonic biosensors are discussed, with particular focus on nanolisted main preparation methods of various nanostructures, such as chemical synthesis, lithography, nanosphere lithography, nanoimprint lithography, etc., and describing their respective advances and challenges from practical applications of plasmon biosensors. Based on these sensing structures, different types of plasmonic biosensors are summarized regarding detecting cancer biomarkers, body fluid, temperature, gas and COVID-19. Last, the existing challenges and prospects of plasmonic biosensors combined with machine learning, mega data analysis and prediction are surveyed.
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Affiliation(s)
- Tongge An
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Jiahong Wen
- The College of Electronics and Information, Hangzhou Dianzi University, Hangzhou 310018, China
- Shangyu Institute of Science and Engineering, Hangzhou Dianzi University, Shaoxing 312000, China
| | - Zhichao Dong
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Yongjun Zhang
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Jian Zhang
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Faxiang Qin
- Institute for Composites Science Innovation, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Yaxin Wang
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
| | - Xiaoyu Zhao
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018, China
- Zhejiang Laboratory, Hangzhou 311100, China
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4
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Wang Y, Chen B, Meng D, Song B, Liu Z, Hu P, Yang H, Ou TH, Liu F, Pi H, Pi I, Pi I, Wu W. Hot Electron-Driven Photocatalysis Using Sub-5 nm Gap Plasmonic Nanofinger Arrays. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:nano12213730. [PMID: 36364506 PMCID: PMC9655529 DOI: 10.3390/nano12213730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/19/2022] [Accepted: 10/21/2022] [Indexed: 06/12/2023]
Abstract
Semiconductor photocatalysis has received increasing attention because of its potential to address problems related to the energy crisis and environmental issues. However, conventional semiconductor photocatalysts, such as TiO2 and ZnO, can only be activated by ultraviolet light due to their wide band gap. To extend the light absorption into the visible range, the localized surface plasmon resonance (LSPR) effect of noble metal nanoparticles (NPs) has been widely used. Noble metal NPs can couple incident visible light energy to strong LSPR, and the nonradiative decay of LSPR generates nonthermal hot carriers that can be injected into adjacent semiconductor material to enhance its photocatalytic activity. Here we demonstrate that nanoimprint-defined gap plasmonic nanofinger arrays can function as visible light-driven plasmonic photocatalysts. The sub-5 nm gaps between pairs of collapsed nanofingers can support ultra-strong plasmon resonance and thus boost the population of hot carriers. The semiconductor material is exactly placed at the hot spots, providing an efficient pathway for hot carrier injection from plasmonic metal to catalytic materials. This nanostructure thus exhibits high plasmon-enhanced photocatalytic activity under visible light. The hot carrier injection mechanism of this platform was systematically investigated. The plasmonic enhancement factor was calculated using the finite-difference time-domain (FDTD) method and was consistent with the measured improvement of the photocatalytic activity. This platform, benefiting from the precise controllable geometry, provides a deeper understanding of the mechanism of plasmonic photocatalysis.
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Affiliation(s)
- Yunxiang Wang
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Buyun Chen
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Deming Meng
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Boxiang Song
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zerui Liu
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Pan Hu
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Hao Yang
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Tse-Hsien Ou
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
| | - Fanxin Liu
- Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, China
| | - Halton Pi
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Irene Pi
- School of Computer Science, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Isleen Pi
- College of Art and Science, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Wei Wu
- Ming Hsieh Department of Electrical and Computer Engineering, University of Southern California, Los Angeles, CA 90089, USA
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5
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Wang Y, Wang Y, Aravind I, Cai Z, Shen L, Zhang B, Wang B, Chen J, Zhao B, Shi H, Dawlaty JM, Cronin SB. In Situ Investigation of Ultrafast Dynamics of Hot Electron-Driven Photocatalysis in Plasmon-Resonant Grating Structures. J Am Chem Soc 2022; 144:3517-3526. [PMID: 35188777 DOI: 10.1021/jacs.1c12069] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Understanding the relaxation and injection dynamics of hot electrons is crucial to utilizing them in photocatalytic applications. While most studies have focused on hot carrier dynamics at metal/semiconductor interfaces, we study the in situ dynamics of direct hot electron injection from metal to adsorbates. Here, we report a hot electron-driven hydrogen evolution reaction (HER) by exciting the localized surface plasmon resonance (LSPR) in Au grating photoelectrodes. In situ ultrafast transient absorption (TA) measurements show a depletion peak resulting from hot electrons. When the sample is immersed in solution under -1 V applied potential, the extracted electron-phonon interaction time decreases from 0.94 to 0.67 ps because of additional energy dissipation channels. The LSPR TA signal is redshifted with delay time because of charge transfer and subsequent change in the dielectric constant of nearby solution. Plateau-like photocurrent peaks appear when exciting a 266 nm linewidth grating with p-polarized (on resonance) light, accompanied by a similar profile in the measured absorptance. Double peaks in the photocurrent measurement are observed when irradiating a 300 nm linewidth grating. The enhancement factor (i.e., reaction rate) is 15.6× between p-polarized and s-polarized light for the 300 nm linewidth grating and 4.4× for the 266 nm linewidth grating. Finite-difference time domain (FDTD) simulations show two resonant modes for both grating structures, corresponding to dipolar LSPR modes at the metal/fused silica and metal/water interfaces. To our knowledge, this is the first work in which LSPR-induced hot electron-driven photochemistry and in situ photoexcited carrier dynamics are studied on the same plasmon resonance structure with and without adsorbates.
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Affiliation(s)
- Yu Wang
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, United States
| | - Yi Wang
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Indu Aravind
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
| | - Zhi Cai
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, United States
| | - Lang Shen
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, United States
| | - Boxin Zhang
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, United States
| | - Bo Wang
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
| | - Jihan Chen
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, United States
| | - Bofan Zhao
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, United States
| | - Haotian Shi
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Jahan M Dawlaty
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Stephen B Cronin
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, United States.,Department of Chemistry, University of Southern California, Los Angeles, California 90089, United States.,Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
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6
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Zhao Q, Yang H, Nie B, Luo Y, Shao J, Li G. Wafer-Scale and Cost-Effective Manufacturing of Controllable Nanogap Arrays for Highly Sensitive SERS Sensing. ACS APPLIED MATERIALS & INTERFACES 2022; 14:3580-3590. [PMID: 34983178 DOI: 10.1021/acsami.1c22465] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The metallic nanogap has been proved as an efficient architecture for surface-enhanced Raman scattering (SERS) applications. Although a lot of nanogap fabrication methods have been proposed in the last few decades, the economical and high-yield manufacturing of sub-10 nm gaps remains a challenge. Here, we present a convenient and cost-effective fabrication method for wafer-scale patterning of metallic nanogaps, which simply combines photolithographic metal patterning, swelling-induced nanocracking, and superimposition metal sputtering without requiring expensive nanofabrication equipment. By controlling the swelling time and metal deposition thickness, the gap size can be precisely defined, down to the sub-10 nm scale. Furthermore, we demonstrate that the fabricated nanogap array can be used as an excellent SERS substrate for molecule measurements and shows a high Raman enhancement factor of ∼108 and a high sensitivity for the detection of rhodamine 6G (R6G) molecules, even down to 10-14 M, indicating an extraordinary capability for single-molecule detection. Due to its high controllability and wafer-scale fabrication capability, this nanogap fabrication method offers a promising route for highly sensitive and economical SERS detections.
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Affiliation(s)
- Qiang Zhao
- Key Laboratory of Optoelectronic Technology and Systems, Ministry of Education, Defense Key Disciplines Lab of Novel Micro-Nano Devices and System Technology, Chongqing University, Chongqing 400044, China
- Micro-/Nano-Technology Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Huan Yang
- Micro-/Nano-Technology Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Bangbang Nie
- Micro-/Nano-Technology Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Yongsong Luo
- Micro-/Nano-Technology Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Jinyou Shao
- Micro-/Nano-Technology Research Center, State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, China
| | - Gang Li
- Key Laboratory of Optoelectronic Technology and Systems, Ministry of Education, Defense Key Disciplines Lab of Novel Micro-Nano Devices and System Technology, Chongqing University, Chongqing 400044, China
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7
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Kim JM, Lee C, Lee Y, Lee J, Park SJ, Park S, Nam JM. Synthesis, Assembly, Optical Properties, and Sensing Applications of Plasmonic Gap Nanostructures. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2006966. [PMID: 34013617 DOI: 10.1002/adma.202006966] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/30/2020] [Indexed: 06/12/2023]
Abstract
Plasmonic gap nanostructures (PGNs) have been extensively investigated mainly because of their strongly enhanced optical responses, which stem from the high intensity of the localized field in the nanogap. The recently developed methods for the preparation of versatile nanogap structures open new avenues for the exploration of unprecedented optical properties and development of sensing applications relying on the amplification of various optical signals. However, the reproducible and controlled preparation of highly uniform plasmonic nanogaps and the prediction, understanding, and control of their optical properties, especially for nanogaps in the nanometer or sub-nanometer range, remain challenging. This is because subtle changes in the nanogap significantly affect the plasmonic response and are of paramount importance to the desired optical performance and further applications. Here, recent advances in the synthesis, assembly, and fabrication strategies, prediction and control of optical properties, and sensing applications of PGNs are discussed, and perspectives toward addressing these challenging issues and the future research directions are presented.
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Affiliation(s)
- Jae-Myoung Kim
- Department of Chemistry, Seoul National University, Seoul, 08826, South Korea
| | - Chungyeon Lee
- Department of Chemistry, Seoul National University, Seoul, 08826, South Korea
| | - Yeonhee Lee
- Department of Chemistry, Seoul National University, Seoul, 08826, South Korea
| | - Jinhaeng Lee
- Department of Chemistry, Sungkyunkwan University, Suwon, 16419, South Korea
| | - So-Jung Park
- Department of Chemistry and Nanoscience, Ewha Womans University, Seoul, 03760, South Korea
| | - Sungho Park
- Department of Chemistry, Sungkyunkwan University, Suwon, 16419, South Korea
| | - Jwa-Min Nam
- Department of Chemistry, Seoul National University, Seoul, 08826, South Korea
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Fang W, Hu P, Wu Z, Xiao Y, Sui Y, Pan D, Su G, Zhu M, Zhan P, Liu F, Wu W. Plasmonic dye-sensitized solar cells through collapsible gold nanofingers. NANOTECHNOLOGY 2021; 32:355301. [PMID: 34034240 DOI: 10.1088/1361-6528/ac04d2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 05/24/2021] [Indexed: 06/12/2023]
Abstract
Plasmonic nanostructures are successfully demonstrated in solar cells due to their broad spectra-selective resonance in the range of ultraviolet to near-infrared, and thus light absorption can be mostly improved and power conversion efficiency (PCE) further. Here, we demonstrate plasmonic dye-sensitized solar cells (DSSCs) using collapsible Au nanofingers to build photoanode to enhance light absorption. In this plasmonic DSSCs, by balancing local field enhancement due to gap-plasmon resonance and dye fluorescence quenching, the optimal gap size in collapsed Au/Al2O3/Au nanofingers is designed by twice the Al2O3thickness and then deposited a TiO2layer as photoanode. The results show that the PCE of DSSCs is mostly improved as compared to DSSCs with photoanode of Au/Al2O3/TiO2films, which can be ascribed to the coupled local field enhancement within the sub-nanometer gaps. In addition, fluorescence of dyes on plasmonic nanofingers is nearly 10 times higher than plain Au/Al2O3/TiO2films, which further proves the dye absorption enhancement. These plasmonic nanofingers enable the precise engineering of gap-plasmon modes and can be scaled up to wafer scale with low cost by the nanoimprint lithography technique, which suggests the feasibility of applying our result in constructing the photoanode for other types of solar cells.
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Affiliation(s)
- Wenruo Fang
- Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, People's Republic of China
| | - Pan Hu
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA 90089, United States of America
| | - Zhenqiu Wu
- Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, People's Republic of China
| | - Youfeng Xiao
- Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, People's Republic of China
| | - Yunxia Sui
- Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, People's Republic of China
| | - Dalong Pan
- Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, People's Republic of China
| | - Guangxu Su
- School of Physics, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Mingwei Zhu
- College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Peng Zhan
- School of Physics, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Fanxin Liu
- Department of Applied Physics, Zhejiang University of Technology, Hangzhou 310023, People's Republic of China
- School of Physics, National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Wei Wu
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA 90089, United States of America
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9
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Song B, Jiang Z, Liu Z, Wang Y, Liu F, Cronin SB, Yang H, Meng D, Chen B, Hu P, Schwartzberg AM, Cabrini S, Haas S, Wu W. Probing the Mechanisms of Strong Fluorescence Enhancement in Plasmonic Nanogaps with Sub-nanometer Precision. ACS NANO 2020; 14:14769-14778. [PMID: 33095557 DOI: 10.1021/acsnano.0c01973] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Plasmon-enhanced fluorescence is demonstrated in the vicinity of metal surfaces due to strong local field enhancement. Meanwhile, fluorescence quenching is observed as the spacing between fluorophore molecules and the adjacent metal is reduced below a threshold of a few nanometers. Here, we introduce a technology, placing the fluorophore molecules in plasmonic hotspots between pairs of collapsible nanofingers with tunable gap sizes at sub-nanometer precision. Optimal gap sizes with maximum plasmon enhanced fluorescence are experimentally identified for different dielectric spacer materials. The ultrastrong local field enhancement enables simultaneous detection and characterization of sharp Raman fingerprints in the fluorescence spectra. This platform thus enables in situ monitoring of competing excitation enhancement and emission quenching processes. We systematically investigate the mechanisms behind fluorescence quenching. A quantum mechanical model is developed which explains the experimental data and will guide the future design of plasmon enhanced spectroscopy applications.
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Affiliation(s)
- Boxiang Song
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, United States
| | - Zhihao Jiang
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
| | - Zerui Liu
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, United States
| | - Yunxiang Wang
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, United States
| | - Fanxin Liu
- Department of Applied Physics, Zhejiang University of Technology, Hangzhou, Zhejiang, China 310023
| | - Stephen B Cronin
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, United States
| | - Hao Yang
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, United States
| | - Deming Meng
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, United States
| | - Buyun Chen
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, United States
| | - Pan Hu
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, United States
| | - Adam M Schwartzberg
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Stefano Cabrini
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Stephan Haas
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089, United States
| | - Wei Wu
- Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, United States
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10
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JIANG S, ESPULGAR WV, LUO X, SAITO M, YOSHIKAWA H, TAMIYA E. SERS Active Hierarchical Nanopillar-huddle Array Fabricated via the Combination of Nanoimprint Lithography and Anodization. ELECTROCHEMISTRY 2020. [DOI: 10.5796/electrochemistry.19-00072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Shu JIANG
- Advanced Photonics and Biosensing Open Innovation Laboratory, AIST-Osaka University, Photonics Center Osaka University
- Department of Applied Physics, Graduate School of Engineering, Osaka University
| | - Wilfred V. ESPULGAR
- Department of Applied Physics, Graduate School of Engineering, Osaka University
| | - Xi LUO
- Advanced Photonics and Biosensing Open Innovation Laboratory, AIST-Osaka University, Photonics Center Osaka University
- Department of Applied Physics, Graduate School of Engineering, Osaka University
| | - Masato SAITO
- Advanced Photonics and Biosensing Open Innovation Laboratory, AIST-Osaka University, Photonics Center Osaka University
- Department of Applied Physics, Graduate School of Engineering, Osaka University
| | - Hiroyuki YOSHIKAWA
- Department of Applied Physics, Graduate School of Engineering, Osaka University
| | - Eiichi TAMIYA
- Department of Applied Physics, Graduate School of Engineering, Osaka University
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11
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Wang Y, Aravind I, Cai Z, Shen L, Gibson GN, Chen J, Wang B, Shi H, Song B, Guignon E, Cady NC, Page WD, Pilar A, Cronin SB. Hot Electron Driven Photocatalysis on Plasmon-Resonant Grating Nanostructures. ACS APPLIED MATERIALS & INTERFACES 2020; 12:17459-17465. [PMID: 32212673 DOI: 10.1021/acsami.0c00066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We demonstrate the hot electron injection of photoexcited carriers in an Ag-based plasmon resonant grating structure. By varying the incident angle of irradiation, sharp dips are observed in the reflectance with p-polarized light (electric field perpendicular to grating lines) when there is wavevector matching between the incident light and the plasmon resonant modes of the grating and no angle dependence is observed with s-polarized light. This configuration enables us to compare photoelectrochemical current produced by plasmon resonant excitation with that of bulk metal interband absorption simply by rotating the polarization of the incident light while keeping all other parameters of the measurement fixed. With 633 nm light, we observed a 12-fold enhancement in the photocurrent (i.e., reaction rate) between resonant and nonresonant polarizations at incident angles of ±7.6° from normal. At 785 nm irradiation, we observed similar resonant profiles to those obtained with 633 nm wavelength light but with a 44-fold enhancement factor. Using 532 nm light, we observed two resonant peaks (with approximately 10× enhancement) in the photocurrent at 19.4° and 28.0° incident angles, each corresponding to higher order modes in the grating with more nodes per period. The lower enhancement factors observed at shorter wavelengths are attributed to interband transitions, which provide a damping mechanism for the plasmon resonance. Finite difference time domain (FDTD) simulations of these grating structures confirm the resonant profiles observed in the angle-dependent spectra of these gratings and provide a detailed picture of the electric field profiles on and off resonance.
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Affiliation(s)
| | | | | | | | - George N Gibson
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, United States
- Ciencia Inc., East Hartford, Connecticut 06108, United States
| | | | | | | | | | - Ernest Guignon
- Ciencia Inc., East Hartford, Connecticut 06108, United States
| | - Nathaniel C Cady
- Colleges of Nanoscale Science & Engineering, SUNY Polytechnic Institute, Albany, New York 12203, United States
| | - William D Page
- Ciencia Inc., East Hartford, Connecticut 06108, United States
| | - Arturo Pilar
- Ciencia Inc., East Hartford, Connecticut 06108, United States
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12
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Sivun D, Klar TA. Optical Coulomb blockade lifting in plasmonic nanoparticle dimers. OPTICS EXPRESS 2020; 28:4115-4126. [PMID: 32122070 DOI: 10.1364/oe.384301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 01/13/2020] [Indexed: 06/10/2023]
Abstract
If two metal nanoparticles are ultimately approached, a tunneling current prevents both an infinite redshift of the bonding dipolar plasmon and an infinite increase of the electric field in the hot spot between the nanoparticles. We argue that a Coulomb blockade suppresses the tunneling current and sustains a redshift even for sub-nanometer approach up to moderate fields. Only for stronger optical fields, the Coulomb blockade is lifted and a charge transfer plasmon is formed. Numerical simulations show that such scenarios are well in reach with manageable nanoparticle dimensions, even at room temperature. Applications may include ultrafast, optically driven switches, photo detectors operating at 500 THz, or highly nonlinear devices.
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13
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Kim I, Mun J, Hwang W, Yang Y, Rho J. Capillary-force-induced collapse lithography for controlled plasmonic nanogap structures. MICROSYSTEMS & NANOENGINEERING 2020; 6:65. [PMID: 34567676 PMCID: PMC8433176 DOI: 10.1038/s41378-020-0177-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 04/23/2020] [Accepted: 04/26/2020] [Indexed: 05/22/2023]
Abstract
The capillary force effect is one of the most important fabrication parameters that must be considered at the micro/nanoscale because it is strong enough to deform micro/nanostructures. However, the deformation of micro/nanostructures due to such capillary forces (e.g., stiction and collapse) has been regarded as an undesirable and uncontrollable obstacle to be avoided during fabrication. Here, we present a capillary-force-induced collapse lithography (CCL) technique, which exploits the capillary force to precisely control the collapse of micro/nanostructures. CCL uses electron-beam lithography, so nanopillars with various shapes can be fabricated by precisely controlling the capillary-force-dominant cohesion process and the nanopillar-geometry-dominant collapse process by adjusting the fabrication parameters such as the development time, electron dose, and shape of the nanopillars. CCL aims to achieve sub-10-nm plasmonic nanogap structures that promote extremely strong focusing of light. CCL is a simple and straightforward method to realize such nanogap structures that are needed for further research such as on plasmonic nanosensors.
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Affiliation(s)
- Inki Kim
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
| | - Jungho Mun
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
| | - Wooseup Hwang
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
| | - Younghwan Yang
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
| | - Junsuk Rho
- Department of Mechanical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
- Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673 Republic of Korea
- National Institute of Nanomaterials and Technology (NINT), Pohang, 37673 Republic of Korea
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14
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Liu F, Song B, Su G, Liang O, Zhan P, Wang H, Wu W, Xie Y, Wang Z. Sculpting Extreme Electromagnetic Field Enhancement in Free Space for Molecule Sensing. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1801146. [PMID: 30003669 DOI: 10.1002/smll.201801146] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 05/26/2018] [Indexed: 05/04/2023]
Abstract
A strongly confined and enhanced electromagnetic (EM) field due to gap-plasmon resonance offers a promising pathway for ultrasensitive molecular detections. However, the maximum enhanced portion of the EM field is commonly concentrated within the dielectric gap medium that is inaccessible to external substances, making it extremely challenging for achieving single-molecular level detection sensitivity. Here, a new family of plasmonic nanostructure created through a unique process using nanoimprint lithography is introduced, which enables the precise tailoring of the gap plasmons to realize the enhanced field spilling to free space. The nanostructure features arrays of physically contacted nanofinger-pairs with a 2 nm tetrahedral amorphous carbon (ta-C) film as an ultrasmall dielectric gap. The high tunneling barrier offered by ta-C film due to its low electron affinity makes an ultranarrow gap and high enhancement factor possible at the same time. Additionally, its high electric permittivity leads to field redistribution and an abrupt increase across the ta-C/air boundary and thus extensive spill-out of the coupled EM field from the gap region with field enhancement in free space of over 103 . The multitude of benefits deriving from the unique nanostructure hence allows extremely high detection sensitivity at the single-molecular level to be realized as demonstrated through bianalyte surface-enhanced Raman scattering measurement.
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Affiliation(s)
- Fanxin Liu
- School of Physics, National Laboratory of Solid State Microstructures, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
- Collaborative Innovation Center for Information Technology in Biological and Medical Physics, and College of Science, Zhejiang University of Technology, Hangzhou, 310023, P. R. China
| | - Boxiang Song
- Department of Electrical Engineering-Electrophysics, University of Southern California, Los Angeles, CA, 90089, USA
| | - Guangxu Su
- School of Physics, National Laboratory of Solid State Microstructures, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Owen Liang
- Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Peng Zhan
- School of Physics, National Laboratory of Solid State Microstructures, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
| | - Han Wang
- Department of Electrical Engineering-Electrophysics, University of Southern California, Los Angeles, CA, 90089, USA
| | - Wei Wu
- Department of Electrical Engineering-Electrophysics, University of Southern California, Los Angeles, CA, 90089, USA
| | - Yahong Xie
- Department of Materials Science and Engineering, University of California Los Angeles, Los Angeles, CA, 90095, USA
- Jonsson Comprehensive Cancer Center, University of California Los Angeles, Los Angeles, CA, 90024, USA
| | - Zhenlin Wang
- School of Physics, National Laboratory of Solid State Microstructures, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, P. R. China
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