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Wagner M, Seifert A, Liz-Marzán LM. Towards multi-molecular surface-enhanced infrared absorption using metal plasmonics. NANOSCALE HORIZONS 2022; 7:1259-1278. [PMID: 36047407 DOI: 10.1039/d2nh00276k] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Surface-enhanced infrared absorption (SEIRA) leads to a largely improved detection of polar molecules, compared to standard infrared absorption. The enhancement principle is based on localized surface plasmon resonances of the substrate, which match the frequency of molecular vibrations in the analyte of interest. Therefore, in practical terms, the SEIRA sensor needs to be tailored to each specific analyte. We review SEIRA sensors based on metal plasmonics for the detection of biomolecules such as DNA, proteins, and lipids. We further focus this review on chemical SEIRA sensors, with potential applications in quality control, as well as on the improvement in sensor geometry that led to the development of multiresonant SEIRA substrates as sensors for multiple analytes. Finally, we give an introduction into the integration of SEIRA sensors with surface-enhanced Raman scattering (SERS).
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Affiliation(s)
- Marita Wagner
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo de Miramón 194, 20014 Donostia-San Sebastián, Spain.
- CIC nanoGUNE, Basque Research and Technology Alliance (BRTA), 20018 Donostia-San Sebastián, Spain
| | - Andreas Seifert
- CIC nanoGUNE, Basque Research and Technology Alliance (BRTA), 20018 Donostia-San Sebastián, Spain
- IKERBASQUE, Basque Foundation for Science, 43009 Bilbao, Spain
| | - Luis M Liz-Marzán
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo de Miramón 194, 20014 Donostia-San Sebastián, Spain.
- IKERBASQUE, Basque Foundation for Science, 43009 Bilbao, Spain
- Centro de Investigación Biomédica en Red, Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), 20014 Donostia-San Sebastián, Spain
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2
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Dao TC, Luong TQN. Fabrication of uniform arrays of silver nanoparticles on silicon by electrodeposition in ethanol solution and their use in SERS detection of difenoconazole pesticide. RSC Adv 2020; 10:40940-40947. [PMID: 35519192 PMCID: PMC9057794 DOI: 10.1039/d0ra08060h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 11/05/2020] [Indexed: 01/07/2023] Open
Abstract
Surface-Enhanced Raman Scattering (SERS) is a technique currently widely used in the identification and quantification of organic and biological molecules at low concentrations, in which an important application is the detection of pesticide residues in food. To accomplish this task, SERS substrates with high Raman enhancement factor and good reproducibility are required. One of the most commonly used SERS substrates is the SERS substrate made of silver nanoparticles immobilized on a solid substrate. In this report we first present the results of electrochemical deposition of silver nanoparticles on the silicon surface using ethanol electrolyte solution. Thanks to both factors, electrochemical deposition (instead of electroless) and ethanol electrolyte (instead of aqueous), under optimal conditions, on the surface of silicon a monolayer of silver nanoparticles grew, which are uniform in shape and size and are arranged very close to each other with nanometer separation. Next we report on the use of fabricated arrays of silver nanoparticles in the role of a SERS substrate. To test the performance of the SERS substrate, the probe molecules used were molecules of difenoconazole, a well-known fungicide. Results showed that difenoconazole could be detected with a detection limit of 0.023 ppm (5.6 × 10-8 M).
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Affiliation(s)
- Tran Cao Dao
- Institute of Materials Science, Vietnam Academy of Science and Technology 18 Hoang Quoc Viet, Cau Giay 100000 Hanoi Vietnam
- Graduate University of Science and Technology, Vietnam Academy of Science and Technology 18 Hoang Quoc Viet, Cau Giay 100000 Hanoi Vietnam
| | - Truc Quynh Ngan Luong
- Institute of Materials Science, Vietnam Academy of Science and Technology 18 Hoang Quoc Viet, Cau Giay 100000 Hanoi Vietnam
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Pacholski C, Rosencrantz S, Rosencrantz RR, Balderas-Valadez RF. Plasmonic biosensors fabricated by galvanic displacement reactions for monitoring biomolecular interactions in real time. Anal Bioanal Chem 2020; 412:3433-3445. [PMID: 32006063 PMCID: PMC7214386 DOI: 10.1007/s00216-020-02414-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 01/01/2020] [Accepted: 01/13/2020] [Indexed: 12/14/2022]
Abstract
Optical sensors are prepared by reduction of gold ions using freshly etched hydride-terminated porous silicon, and their ability to specifically detect binding between protein A/rabbit IgG and asialofetuin/Erythrina cristagalli lectin is studied. The fabrication process is simple, fast, and reproducible, and does not require complicated lab equipment. The resulting nanostructured gold layer on silicon shows an optical response in the visible range based on the excitation of localized surface plasmon resonance. Variations in the refractive index of the surrounding medium result in a color change of the sensor which can be observed by the naked eye. By monitoring the spectral position of the localized surface plasmon resonance using reflectance spectroscopy, a bulk sensitivity of 296 nm ± 3 nm/RIU is determined. Furthermore, selectivity to target analytes is conferred to the sensor through functionalization of its surface with appropriate capture probes. For this purpose, biomolecules are deposited either by physical adsorption or by covalent coupling. Both strategies are successfully tested, i.e., the optical response of the sensor is dependent on the concentration of respective target analyte in the solution facilitating the determination of equilibrium dissociation constants for protein A/rabbit IgG as well as asialofetuin/Erythrina cristagalli lectin which are in accordance with reported values in literature. These results demonstrate the potential of the developed optical sensor for cost-efficient biosensor applications. Graphical abstract.
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Affiliation(s)
- Claudia Pacholski
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14476, Potsdam, Germany
| | - Sophia Rosencrantz
- Fraunhofer Institute for Applied Polymer Research IAP, Biofunctionalized Materials and (Glyco)Biotechnology, Geiselbergstraße 69, 14476, Potsdam, Germany
| | - Ruben R Rosencrantz
- Fraunhofer Institute for Applied Polymer Research IAP, Biofunctionalized Materials and (Glyco)Biotechnology, Geiselbergstraße 69, 14476, Potsdam, Germany
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Gkogkou D, Shaykhutdinov T, Kratz C, Oates TWH, Hildebrandt P, Weidinger IM, Ly KH, Esser N, Hinrichs K. Gradient metal nanoislands as a unified surface enhanced Raman scattering and surface enhanced infrared absorption platform for analytics. Analyst 2019; 144:5271-5276. [DOI: 10.1039/c9an00839j] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A metal nanoisland layer with varying plasmonic responses offers surface enhanced Raman scattering and infrared absorption optimal sites on a single surface.
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Affiliation(s)
- Dimitra Gkogkou
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V
- ISAS Berlin
- 12489 Berlin
- Germany
| | - Timur Shaykhutdinov
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V
- ISAS Berlin
- 12489 Berlin
- Germany
| | - Christoph Kratz
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V
- ISAS Berlin
- 12489 Berlin
- Germany
| | - Thomas W. H. Oates
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V
- ISAS Berlin
- 12489 Berlin
- Germany
| | | | - Inez M. Weidinger
- Technische Universität Dresden
- Department of Chemistry and Food Chemistry
- 01062 Dresden
- Germany
| | - Khoa Hoang Ly
- Technische Universität Dresden
- Department of Chemistry and Food Chemistry
- 01062 Dresden
- Germany
| | - Norbert Esser
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V
- ISAS Berlin
- 12489 Berlin
- Germany
| | - Karsten Hinrichs
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V
- ISAS Berlin
- 12489 Berlin
- Germany
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5
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Immobilization of silver nanoparticles into POEGMA polymer brushes as SERS-active substrates. SURF INTERFACE ANAL 2016. [DOI: 10.1002/sia.6137] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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6
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Zhang Z, Liao F, Ma S, Gao S, Shao M. SERS and FDTD simulation of gold nanoparticles grafted on germanium wafer via galvanic displacement. SURF INTERFACE ANAL 2014. [DOI: 10.1002/sia.5727] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Zhaoshun Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM); Soochow University; Suzhou 215123 China
| | - Fan Liao
- Institute of Functional Nano & Soft Materials (FUNSOM); Soochow University; Suzhou 215123 China
| | - Shuzhen Ma
- Institute of Functional Nano & Soft Materials (FUNSOM); Soochow University; Suzhou 215123 China
| | - Suning Gao
- Institute of Functional Nano & Soft Materials (FUNSOM); Soochow University; Suzhou 215123 China
| | - Mingwang Shao
- Institute of Functional Nano & Soft Materials (FUNSOM); Soochow University; Suzhou 215123 China
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Maggie Liou YC, Chen JY, Yang J. Distance-dependent Enhancement in Raman Spectroscopy Probed by Conjugated Molecules with Different Molecular Lengths. J CHIN CHEM SOC-TAIP 2014. [DOI: 10.1002/jccs.201300651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Liou YCM, Chen JY, Yang J. Enhancement of Raman scattering for silver nanoparticles located on electrolessly roughened silicon. APPLIED SPECTROSCOPY 2014; 68:172-178. [PMID: 24480272 DOI: 10.1366/13-07162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
To study the effect of roughness of a supporting substrate to Raman enhancement, silver nanoparticles (AgNPs) were prepared on Si with different degrees of roughness. To roughen the surface of silicon, electroless displacement was used first to grow AgNPs on smooth Si. By chemically removing the resulting AgNPs, an electrolessly roughened Si surface can be exposed. A second electroless displacement then was performed to grow new AgNPs on the roughened Si crystal to form surface-enhanced Raman scattering substrates. Another approach, called the protecting method, also was proposed and demonstrated to structure AgNPs on surface-roughened Si. In this second method, electroless displacement also was used to grow AgNPs on the Si crystal. The resulting AgNPs then were protected by thio compounds to control removal of the outer layer of AgNPs, thereby exposing the underlying AgNPs located directly on the electroless roughened Si surface. Results indicate that the structure of AgNPs on roughened Si surfaces provides approximately two orders of magnitude higher enhancement than AgNPs on non-roughened Si, and the substrates prepared in this work are highly sensitive, with enhancement factors reaching 10(8).
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Affiliation(s)
- Yen-Chen Maggie Liou
- Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan, Republic of China
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D'Andrea C, Bochterle J, Toma A, Huck C, Neubrech F, Messina E, Fazio B, Maragò OM, Di Fabrizio E, Lamy de La Chapelle M, Gucciardi PG, Pucci A. Optical nanoantennas for multiband surface-enhanced infrared and Raman spectroscopy. ACS NANO 2013; 7:3522-3531. [PMID: 23530556 DOI: 10.1021/nn4004764] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In this article we show that linear nanoantennas can be used as shared substrates for surface-enhanced Raman and infrared spectroscopy (SERS and SEIRS, respectively). This is done by engineering the plasmonic properties of the nanoantennas, so to make them resonant in both the visible (transversal resonance) and the infrared (longitudinal resonance), and by rotating the excitation field polarization to selectively take advantage of each resonance and achieve SERS and SEIRS on the same nanoantennas. As a proof of concept, we have fabricated gold nanoantennas by electron beam lithography on calcium difluoride (1-2 μm long, 60 nm wide, 60 nm high) that exhibit a transverse plasmonic resonance in the visible (640 nm) and a particularly strong longitudinal dipolar resonance in the infrared (tunable in the 1280-3100 cm(-1) energy range as a function of the length). SERS and SEIRS detection of methylene blue molecules adsorbed on the nanoantenna's surface is accomplished, with signal enhancement factors of 5×10(2) for SERS (electromagnetic enhancement) and up to 10(5) for SEIRS. Notably, we find that the field enhancement provided by the transverse resonance is sufficient to achieve SERS from single nanoantennas. Furthermore, we show that by properly tuning the nanoantenna length the signals of a multitude of vibrational modes can be enhanced with SEIRS. This simple concept of plasmonic nanosensor is highly suitable for integration on lab-on-a-chip schemes for label-free chemical and biomolecular identification with optimized performances.
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Affiliation(s)
- Cristiano D'Andrea
- CNR IPCF Istituto per i Processi Chimico-Fisici, Viale F. Stagno D'Alcontres 37, I-98156, Messina, Italy
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10
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Dendisova-Vyskovska M, Broncova G, Clupek M, Prokopec V, Matejka P. In situ SERS spectroelectrochemical analysis of antioxidants deposited on copper substrates: what is the effect of applied potential on sorption behavior? SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 99:196-204. [PMID: 23064550 DOI: 10.1016/j.saa.2012.09.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 08/30/2012] [Accepted: 09/09/2012] [Indexed: 06/01/2023]
Abstract
The detection of p-coumaric acid and ferulic acid using a combined in situ electrochemical and surface-enhanced Raman scattering spectroscopic technique in specially made electrode cell is described. New in situ spectroelectrochemical cell was designed as the three-electrode arrangement connected via positioning device to fiber-optic probe of Raman spectrometer Dimension P2 (excitation wavelength 785 nm). In situ SERS spectra of p-coumaric acid and ferulic acid were recorded at varying applied negative potentials to copper substrates. The spectral intensities and shapes of bands as well as spatial orientation of molecules on the surface depend significantly on varying values of the applied electrode potential. The change of electrode potential influences analyte adsorption/desorption behavior on the surface of copper substrates, affecting the reversibility of the whole process and overall spectral enhancement level. Principal component analysis is used to distinguish several stages of spectral variations on potential changes.
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Affiliation(s)
- Marcela Dendisova-Vyskovska
- Institute of Chemical Technology Prague, Department of Analytical Chemistry, Technicka 5, 166 28 Prague 6, Czech Republic.
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11
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Cialla D, März A, Böhme R, Theil F, Weber K, Schmitt M, Popp J. Surface-enhanced Raman spectroscopy (SERS): progress and trends. Anal Bioanal Chem 2011; 403:27-54. [PMID: 22205182 DOI: 10.1007/s00216-011-5631-x] [Citation(s) in RCA: 402] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 11/10/2011] [Accepted: 12/01/2011] [Indexed: 12/12/2022]
Abstract
Surface-enhanced Raman spectroscopy (SERS) combines molecular fingerprint specificity with potential single-molecule sensitivity. Therefore, the SERS technique is an attractive tool for sensing molecules in trace amounts within the field of chemical and biochemical analytics. Since SERS is an ongoing topic, which can be illustrated by the increased annual number of publications within the last few years, this review reflects the progress and trends in SERS research in approximately the last three years. The main reason why the SERS technique has not been established as a routine analytic technique, despite its high specificity and sensitivity, is due to the low reproducibility of the SERS signal. Thus, this review is dominated by the discussion of the various concepts for generating powerful, reproducible, SERS-active surfaces. Furthermore, the limit of sensitivity in SERS is introduced in the context of single-molecule spectroscopy and the calculation of the 'real' enhancement factor. In order to shed more light onto the underlying molecular processes of SERS, the theoretical description of SERS spectra is also a growing research field and will be summarized here. In addition, the recording of SERS spectra is affected by a number of parameters, such as laser power, integration time, and analyte concentration. To benefit from synergies, SERS is combined with other methods, such as scanning probe microscopy and microfluidics, which illustrates the broad applications of this powerful technique.
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Affiliation(s)
- Dana Cialla
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Jena, Germany
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Chang RLJ, Yang J. para-Mercaptobenzoic acid-modified silver nanoparticles as sensing media for the detection of ammonia in air based on infrared surface enhancement effect. Analyst 2011; 136:2988-95. [PMID: 21647481 DOI: 10.1039/c0an00884b] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To utilize the large signals provided by surface-enhanced infrared absorption (SEIRA) measurements for chemical sensing, a new sensing scheme was proposed and demonstrated for detection of ammonia in air samples. To increase the SEIRA effect, a sensing phase composed of multi-layers of silver nanoparticles (AgNPs) was prepared using a chemically controlled electroless deposition method. para-Mercaptobenzoic acid (pMBA) served as the controlling agent in formation of AgNPs, a surface modification agent of AgNPs for sensing, and a stabilizer to protect the AgNPs from coagulation and oxidation. The sensing approach utilized the interaction between pMBA and ammonia, which involves the formation of carboxylate-ammonium complex. After interaction, the enhanced IR absorption bands of pMBA on AgNPs were significantly changed and able to provide quantitative information on the ammonia concentrations. To optimize the conditions for preparing sensing elements, parameters used to form multi-layers of AgNPs were systematically varied and their corresponding sensitivities in detection of ammonia were recorded. The results indicate that AgNPs with diameters in the range of 100 nm provided the best performance in terms of detecting ammonia via the SEIRA effect. Also, the analytical signal generally increased as the number of layers of AgNPs increased, but was limited to certain layers, depending on the reaction conditions used in preparation of AgNPs. The sensing elements were found to be highly selective to ammonia and the detection limit approached 150 ppb with a linear range up to 25 ppm.
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Affiliation(s)
- Ruo-Lan Joan Chang
- Department of Chemistry, National Chung-Hsing University, Taichung, 402, Taiwan
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Prokopec V, Dendisová-Vyškovská M, Kokaislová A, Čejková J, Člupek M, Matějka P. Spectroscopic study of SERS- and SEIRA-activity of copper large-scaled surface substrates prepared by electrochemical deposition: What is the role of oxidation–reduction cycle treatment? J Mol Struct 2011. [DOI: 10.1016/j.molstruc.2010.11.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Jang YH, Hwang S, Cho K, Lim M, Joo T, Choi S, Kim J, Joo SW. Reversible adsorption change of 2-amino-4,5-imidazoledicarbonitrile on Ag electrode surfaces by potential-dependent surface-enhanced Raman scattering. SURF INTERFACE ANAL 2011. [DOI: 10.1002/sia.3626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Rao GPC, Yang J. Chemical reduction method for preparation of silver nanoparticles on a silver chloride substrate for application in surface-enhanced infrared optical sensors. APPLIED SPECTROSCOPY 2010; 64:1094-1099. [PMID: 20925978 DOI: 10.1366/000370210792973640] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A new method for the preparation of silver nanoparticles (AgNPs) on silver chloride discs was developed to integrate the unique properties of plasmonic nanoparticles into infrared optical sensing technologies. AgNP layers exhibiting strong infrared surface enhancement were prepared by reacting silver chloride discs in a solution containing hydrazine, which acts as a reducing agent. The silver ions in the outer layer of the disc could be reduced under proper conditions and the reduced silver coagulated to form suitable AgNPs for surface-enhanced infrared absorption (SEIRA) measurements. To examine the influences of the reaction solution composition and also to optimize preparation of SEIRA substrates, factors such as pH value, reaction time, and concentration of reducing agent were examined. Results indicated that both the concentrations of hydrazine and hydroxide strongly influenced the SEIRA signals. The strongest signals were observed when AgNPs on a AgCl substrate were prepared by using a reducing solution of 20 mM NaOH with 0.75 mM hydrazine. Using the optimized substrates, intense SEIRA spectra were observed with an enhancement factor around two orders of magnitude compared to measurements made using conventional sampling techniques.
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Brejna PR, Griffiths PR. Electroless deposition of silver onto silicon as a method of preparation of reproducible surface-enhanced Raman spectroscopy substrates and tip-enhanced Raman spectroscopy tips. APPLIED SPECTROSCOPY 2010; 64:493-499. [PMID: 20482967 DOI: 10.1366/000370210791211682] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A simple method for the production of silver nanoparticles on a silicon substrate that is suitable for surface-enhanced Raman spectroscopy (SERS) is presented. The method is based on spontaneous reduction of Ag(+) ions by elemental silicon. The oxide layer is removed from the surface of a silicon disk by etching with dilute HF that is present in the same dilute solution of silver nitrate that is used to form the silver nanoparticles. By controlling the concentrations of HF and AgNO(3), the morphology of the deposited silver nanostructures can be varied dramatically. The reproducibility of SERS measurements for substrates produced with a given concentration of HF and AgNO(3) is good (relative standard deviation approximately 10%). The application was extended to coating the tips of silicon cantilevers designed for atomic force microscopy (AFM) with silver nanoparticles to permit measurements of tip-enhanced Raman spectra (TERS). The feasibility of TERS measurements with AFM tips prepared in this way is demonstrated.
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Chang RLJ, Yang J. Characterization of thio compounds for a surface-controlled electroless deposition method in the preparation of silver nanoparticles on germanium for surface-enhanced infrared absorption measurements. APPLIED SPECTROSCOPY 2010; 64:219-230. [PMID: 20149284 DOI: 10.1366/000370210790619591] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
An electroless re-growing method has been developed to prepare silver nanoparticles (Ag-NPs) on substrates for surface-enhanced infrared absorption (SEIRA) measurements. To understand the roles of specific molecules in controlling the properties of Ag-NPs on germanium substrates, thio compounds bearing different functional groups were examined systematically. Four classes of thio compounds were examined in this work, including aromatic thio compounds with second functional group, alkyl thio compounds with second functional group, structural isomers of aromatic thio compounds, and alkyl thio compounds with different alkyl chain lengths. By correlating SEIRA signals with the observed morphologies of the Ag-NPs, it was found that thio compounds bearing amine polar functional groups produced Ag-NPs that were the most regular in shape and size. Also, aromatic thio compounds provided better performance than did alkyl thio compounds in terms of producing suitable shapes and sizes for SEIRA. The Ag-NPs prepared in this work were generally around 50 nm in diameter and round in shape. To examine the prepared substrates for chemical sensing purposes, the enhancement factors were determined by deposition of para-nitrothiophenol (pNTP) on the Ag-NP substrates produced by this surface-controlled electroless deposition method. Results indicated that the surface of the newly formed Ag-NPs actively interacted with pNTP, and the enhancement factors obtained ranged from 50 to 150.
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Affiliation(s)
- Ruo-Lan Joan Chang
- Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan
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Chang RLJ, Yang J. Surface-controlled electroless deposition method in the preparation of stacked silver nanoparticles on germanium for surface-enhanced infrared absorption measurements. APPLIED SPECTROSCOPY 2010; 64:211-218. [PMID: 20149283 DOI: 10.1366/000370210790619555] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A new method to prepare highly sensitive sensing elements for surface-enhanced infrared absorption (SEIRA) measurements was investigated. A surface-controlled procedure was employed to grow round and stacked silver nanoparticles (Ag-NPs) on germanium substrates. In this method, an initial layer of Ag-NPs was prepared using a common method of electroless deposition. After subsequently placing a controlled layer of p-aminothiophenol (pATP) on the surface of the initial layer of Ag-NPs, the substrates were placed in a silver nitrate solution to grow a second layer of Ag-NPs. By repeating these growing procedures, multi-layers of stacked Ag-NPs can be obtained. To examine the influence of morphology of the formed Ag-NPs on the resulting SEIRA signals, the factors affecting the reactions were systematically examined. These factors included the concentrations of silver nitrates, the reaction times to prepare both the initial layer and the second layer of Ag-NPs, and the coverage of pATP. Results indicate that the Ag-NPs making up the second layer were round in shape and much more densely distributed than those in the initial layer. The observed SEIRA spectra did not show derivative-shaped absorption bands for pATP on the Ag-NPs after re-growth, indicating that pATP was sandwiched between the two layers of Ag-NPs, preventing the nanoparticles from coming into direct contact with one another. Also, the SEIRA signals of the controlled molecules between the particles were found to be two to five times more intense than the signals before growing another layer of Ag-NPs. The reaction conditions can be adjusted to vary the morphology and thickness of the Ag-NP layers, and, by repeating the growing procedures, a thick layer of stacked Ag-NPs with suitable size for SEIRA measurements can be obtained that is highly suited to chemical sensing applications.
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Affiliation(s)
- Ruo-Lan Joan Chang
- Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan
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Griffiths PR, Heaps DA, Brejna PR. The gas chromatography/infrared interface: past, present, and future. APPLIED SPECTROSCOPY 2008; 62:259A-70A. [PMID: 18926011 DOI: 10.1366/000370208786049213] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Peter R Griffiths
- Department of Chemistry, University of Idaho, Moscow, Idaho 83844-2343, USA
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