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Yang L, Nandi P, Ma Y, Liu J, Mirsaidov U, Huang Z. Binary Chiral Nanoparticles Exhibit Amplified Optical Activity and Enhanced Refractive Index Sensitivity. Small 2020; 16:e1906048. [PMID: 31961482 DOI: 10.1002/smll.201906048] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 12/09/2019] [Indexed: 06/10/2023]
Abstract
Metallic chiral nanoparticles (CNPs) with a nominal helical pitch (P) of sub-10 nm contain inherent chirality and are promisingly applied to diverse prominent enantiomer-related applications. However, the sub-wavelength P physically results in weak optical activity (OA) to prohibit the development of these applications. Herein, a facile method to amplify the CNPs' OA by alloying the host CNPs with metals through a three-step layer-by-layer glancing angle deposition (GLAD) method is devised. Promoted by the GLAD-induced heating effect, the solute metallic atoms diffuse into the host CNPs to create binary alloy CNPs. Chiral alloying not only induces the plasmonic OA of the diffused solute and the created alloys but also amplifies that of the host CNPs, generally occurring for alloying Ag CNPs with diverse metals (including Cu, Au, Al, and Fe) and alloying Cu CNPs with Ag. Furthermore, the chiral alloying leads to an enhancement of refractive index sensitivity of the CNPs. The alloy CNPs with amplified plasmonic OA pave the way for potentially developing important chirality-related applications in the fields of heterogeneous asymmetric catalysis, enantiodifferentiation, enantioseparation, biosensing, and bioimaging.
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Affiliation(s)
- Lin Yang
- Department of Physics, Hong Kong Baptist University, Kowloon Tong, Kowloon, Hong Kong SAR, China
- HKBU Institute of Research and Continuing Education, 9F, The Industrialization Complex of Shenzhen Virtual University Park, No. 2 Yuexing Third Road, South Zone, Hi-tech Industrial Park, Nanshan District, Shenzhen, Guangdong, 518057, China
| | - Proloy Nandi
- Centre for BioImaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore, 117557, Singapore
| | - Yicong Ma
- Department of Physics, Hong Kong Baptist University, Kowloon Tong, Kowloon, Hong Kong SAR, China
| | - Junjun Liu
- Department of Physics, Hong Kong Baptist University, Kowloon Tong, Kowloon, Hong Kong SAR, China
- HKBU Institute of Research and Continuing Education, 9F, The Industrialization Complex of Shenzhen Virtual University Park, No. 2 Yuexing Third Road, South Zone, Hi-tech Industrial Park, Nanshan District, Shenzhen, Guangdong, 518057, China
| | - Utkur Mirsaidov
- Centre for BioImaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore, 117557, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, Department of Physics, National University of Singapore, Singapore, 117551, Singapore
| | - Zhifeng Huang
- Department of Physics, Hong Kong Baptist University, Kowloon Tong, Kowloon, Hong Kong SAR, China
- HKBU Institute of Research and Continuing Education, 9F, The Industrialization Complex of Shenzhen Virtual University Park, No. 2 Yuexing Third Road, South Zone, Hi-tech Industrial Park, Nanshan District, Shenzhen, Guangdong, 518057, China
- Institute of Advanced Materials, State Key Laboratory of Environmental and Biological Analysis, Golden Meditech Centre for NeuroRegeneration Sciences, Hong Kong Baptist University, Kowloon Tong, Kowloon, Hong Kong SAR, China
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Figueiredo NM, Vaz F, Cunha L, Cavaleiro A. Au-WO 3 Nanocomposite Coatings for Localized Surface Plasmon Resonance Sensing. Materials (Basel) 2020; 13:E246. [PMID: 31935920 DOI: 10.3390/ma13010246] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 01/01/2020] [Accepted: 01/03/2020] [Indexed: 11/17/2022]
Abstract
Localized surface plasmon resonance (LSPR) gas sensors are gaining increasing importance due to their unique tuneable functional properties. Au-WO3−x nanocomposite coatings, in particular, can be outstandingly sensitive to many different gases. However, a proper understanding of their optical properties and the way in which those properties are correlated to their structure/microstructure, is still needed. In this work, Au-WO3 nanocomposite coatings, with Au contents between 0–11 atomic percent, were grown using reactive magnetron co-sputtering technique and were characterized concerning their optical response. The precipitation of Au nanoparticles in the oxide matrix was promoted through thermal annealing treatments until 500 °C. Along with the Au nanoparticles’ morphological changes, the annealing treatments stimulated the crystallization of WO3, together with the appearance of oxygen-deficient WO3−x phases. Through theoretical simulations, we have related the LSPR effect with the different structural and morphological variations (namely, size and distribution of the nanoparticles and their local environment), which were a function of the Au content and annealing temperature. Our results suggest that local voids were present in the vicinity of the Au nanoparticles, for all temperature range, and that they should be present in a wide variety of Au-WO3 nanocomposites. A theoretical study concerning the refractive index sensitivity was carried out in order to predict the optimal coating design parameters for gas sensing experiments.
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Bhalla N, Jain A, Lee Y, Shen AQ, Lee D. Dewetting Metal Nanofilms-Effect of Substrate on Refractive Index Sensitivity of Nanoplasmonic Gold. Nanomaterials (Basel) 2019; 9:E1530. [PMID: 31717894 DOI: 10.3390/nano9111530] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 10/24/2019] [Accepted: 10/25/2019] [Indexed: 12/16/2022]
Abstract
The localized surface plasmon resonance (LSPR) sensitivity of metal nanostructures is strongly dependent on the interaction between the supporting substrate and the metal nanostructure, which may cause a change in the local refractive index of the metal nanostructure. Among various techniques used for the development of LSPR chip preparation, solid-state dewetting of nanofilms offers fast and cost effective methods to fabricate large areas of nanostructures on a given substrate. Most of the previous studies have focused on the effect of the size, shape, and inter-particle distance of the metal nanostructures on the LSPR sensitivity. In this work, we reveal that the silicon-based supporting substrate influences the LSPR associated refractive index sensitivity of gold (Au) nanostructures designed for sensing applications. Specifically, we develop Au nanostructures on four different silicon-based ceramic substrates (Si, SiO2, Si3N4, SiC) by thermal dewetting process and demonstrate that the dielectric properties of these ceramic substrates play a key role in the LSPR-based refractive index (RI) sensitivity of the Au nanostructures. Among these Si-supported Au plasmonic refractive index (RI) sensors, the Au nanostructures on the SiC substrates display the highest average RI sensitivity of 247.80 nm/RIU, for hemispherical Au nanostructures of similar shapes and sizes. Apart from the significance of this work towards RI sensing applications, our results can be advantageous for a wide range of applications where sensitive plasmonic substrates need to be incorporated in silicon based optoelectronic devices.
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Al-Jawdah A, Nabok A, Jarrah R, Holloway A, Tsargorodska A, Takacs E, Szekacs A. Mycotoxin Biosensor Based on Optical Planar Waveguide. Toxins (Basel) 2018; 10:E272. [PMID: 29970806 DOI: 10.3390/toxins10070272] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 06/06/2018] [Accepted: 06/25/2018] [Indexed: 11/17/2022] Open
Abstract
The research aim of this work is to develop a simple and highly sensitive optical biosensor for detection of mycotoxins. This sensor is built on a planar waveguide operating on the polarization interferometry principle, i.e., detecting a phase shift between p- and s-components of polarized light developed during the binding of analyte molecules. The operation of the proposed sensor is similar to that of a Mach⁻Zehnder interferometer, while its design is much simpler and it does not require splitting the waveguide into two arms. The refractive index sensitivity of the polarization interferometer sensor was in the range of 5200 radians per refractive index unit (RIU). Several tests were conducted to detect ochratoxin A (OTA) at different concentrations in direct immunoassay with specific antibodies immobilized in the sensing window. The lowest concentration of OTA of 0.01 ng/mL caused a phase shift of nearly one period. The results obtained prove high sensitivity of the sensors, which are capable of detecting even lower concentrations of mycotoxins at the ppt (part-per-trillion) level.
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Hsu HC, Hsieh TS, Chen YC, Chen HE, Tsai L, Chiang CC. Fiber-Optic Thermal Sensor for TiN Film Crack Monitoring. Materials (Basel) 2017; 10:E1297. [PMID: 29137131 DOI: 10.3390/ma10111297] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/02/2017] [Accepted: 11/07/2017] [Indexed: 11/16/2022]
Abstract
The study focuses on the thermal and temperature sensitivity behavior of an optical fiber sensor device. In this article, a titanium nitride (TiN)-coated fiber Bragg grating (FBG) sensor fabricated using an ion beam sputtering system was investigated. The reflection spectra of the FBG sensor were tested using R-soft optical software to simulate the refractive index sensitivity. In these experiments, the temperature sensitivity of the TiN FBG was measured at temperatures ranging from 100 to 500 °C using an optical spectrum analyzer (OSA). The results showed that the temperature sensitivity of the proposed TiN FBG sensor reached 12.8 pm/°C for the temperature range of 100 to 300 °C and 20.8 pm/°C for the temperature range of 300 to 500 °C. Additionally, we found that the produced oxidation at temperatures of 400–500 °C caused a crack, with the crack becoming more and more obvious at higher and higher temperatures.
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Kedem O, Vaskevich A, Rubinstein I. Improved Sensitivity of Localized Surface Plasmon Resonance Transducers Using Reflection Measurements. J Phys Chem Lett 2011; 2:1223-1226. [PMID: 26295330 DOI: 10.1021/jz200482f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The refractive index sensitivity (RIS) of a localized surface plasmon resonance (LSPR) transducer is one of the key parameters determining its effectiveness in sensing applications. LSPR spectra of nanoparticulate gold films, including Au island films prepared by evaporation on glass and annealing as well as immobilized Au nanoparticle (NP) films, were measured in the transmission and reflection modes. It is shown that the RIS, measured as the wavelength shift in solvents with varying refractive index (RI), is significantly higher in reflection measurements.
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Affiliation(s)
- Ofer Kedem
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Alexander Vaskevich
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Israel Rubinstein
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
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