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Miryousefi N, Varmazyad M, Ghasemi F. Synthesis of Au@Ag core-shell nanorods with tunable optical properties. NANOTECHNOLOGY 2024; 35:395605. [PMID: 38865976 DOI: 10.1088/1361-6528/ad572b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 06/12/2024] [Indexed: 06/14/2024]
Abstract
The synthesis of noble metal nanostructures with adjustable optical properties is essential due to their potential applications in various fields such as imaging, (bio) sensors, and catalysis. In this study, Au@Ag core-shell nanorods were synthesized with tunable optical properties. The synthesis process includes a two-stage approach: first, gold nanorods were synthesized through seed-mediated growth, and in the second stage, these gold nanorods were used as seeds to synthesize Au@Ag core-shell nanorods through the silver deposition process. Tunable core-shell nanorods were produced by changing the concentration of silver ions, reducing agent, stabilizing agent, seeds, and buffer as well as pH and the reaction time. Transmission electron microscopy images demonstrated the formation of the Au@Ag core-shell nanorod structure. In addition, UV-visible spectroscopy revealed the peak height and its shift towards shorter wavelengths, demonstrating the tunable optical properties of the synthesized nanorods. Overall, in this study, we demonstrated the synthesis of Au@Ag core-shell nanorods with adjustable plasmonic optical properties that could be changed by precisely controlling the thickness of the silver shell on the surface of the gold core.
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Affiliation(s)
- Navid Miryousefi
- Department of Nanotechnology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research, Education, and Extension Organization (AREEO), Karaj, Iran
| | - Mahboubeh Varmazyad
- Drug Discovery Institute, University of Pittsburgh, Pittsburgh, PA 15261, United States of America
| | - Forough Ghasemi
- Department of Nanotechnology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research, Education, and Extension Organization (AREEO), Karaj, Iran
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Gomrok S, Eldridge BK, Chaffin EA, Barr JW, Huang X, Hoang TB, Wang Y. Plasmonic couplings in Ag-Au heterodimers. J Chem Phys 2024; 160:144706. [PMID: 38591683 PMCID: PMC11006426 DOI: 10.1063/5.0196256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 03/22/2024] [Indexed: 04/10/2024] Open
Abstract
The plasmonic coupling between silver (Ag) and gold (Au) nanoparticles (NPs) under four polarization modes was examined: a longitudinal mode (L-mode), where the electric field of a linearly polarized incident light parallels the dimer axis, and three transverse modes (T-modes), where the electric field of the light is perpendicular to the dimer axis. The coupling was studied using the discrete dipole approximation followed by an in-house postprocessing code that determines the extinction (Qext), absorption (Qabs), and near-field (Qnf) spectra from the individual NPs as well as the whole system. In agreement with the literature results, the extinction/absorption spectra of the whole dimer have two peaks, one near the Ag localized surface plasmon resonance (LSPR) region and the other at the Au LSPR region, with the peak at Ag LSPR being reduced in all modes and the peak at Au LSPR being red-shifted and increased in the L-mode but not in the T-modes. It is further shown that the scattering at the Ag LSPR region is reduced and becomes less than the isolated Ag NPs, but the absorption at the Ag LSPR is increased and becomes greater than the isolated Ag NPs for the 50 nm Ag-Au heterodimer. This suggests that the scattering from Ag NPs is being reabsorbed by the neighboring Au NPs due to the interband electronic transition in Au at that wavelength range. The Qext from the individual NP in the heterodimer shows the presence of the Fano profile on the Au NP but not on the Ag NP. This phenomenon was further investigated by using a dielectric particle (DP) placed near the Ag or Au NPs. The Fano profile appears in the absorbing DP spectra placed near either Ag or Au NPs. However, the Fano profile is masked upon further increases in the refractive index value of the DP particle. This explains the absence of a Fano profile on the Ag NPs in the Ag-Au heterodimer. The large near-field enhancement on both Ag and Au NPs at the Au plasmonic wavelength in the L-mode for large NPs was investigated through a DP-Au system. The large enhancement was shown to arise from a large imaginary component of the DP refractive index and a small real component. Through examination of both the near- and far-field properties of the individual NPs as well as the whole system and examinations of DP-Ag and DP-Au systems, our study provides a new understanding of the couplings between Ag and Au NPs.
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Affiliation(s)
- Saghar Gomrok
- Department of Chemistry, The University of Memphis, Memphis, Tennessee 38152, USA
| | | | - Elise A. Chaffin
- Department of Chemistry, Freed-Hardeman University, Henderson, Tennessee 38340, USA
| | - James W. Barr
- Department of Chemistry, Freed-Hardeman University, Henderson, Tennessee 38340, USA
| | - Xiaohua Huang
- Department of Chemistry, The University of Memphis, Memphis, Tennessee 38152, USA
| | - Thang B. Hoang
- Department of Physics, The University of Memphis, Memphis, Tennessee 38152, USA
| | - Yongmei Wang
- Department of Chemistry, The University of Memphis, Memphis, Tennessee 38152, USA
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He LB, Shangguan L, Ran YT, Zhu C, Lu ZY, Zhu JH, Yu DJ, Kan CX, Sun LT. Revealing the alloying and dealloying behaviours in AuAg nanorods by thermal stimulus. NANOSCALE ADVANCES 2023; 5:685-692. [PMID: 36756526 PMCID: PMC9890656 DOI: 10.1039/d2na00746k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 12/07/2022] [Indexed: 06/18/2023]
Abstract
Binary metallic nanocrystals are attractive as they offer an extra degree of freedom for structure and phase modulation to generate synergistic effects and extraordinary properties. However, whether the binary structures and phases at the nanoscale still follow the rules established on the bulk counterparts remains unclear. In this work, AuAg nanorods were used as a sample to probe into this issue. An in situ heating method by combining aberration-corrected transmission electron microscopes with a chip-based heating holder was employed to perform the heating experiments. It was found that the AuAg nanorods, which initially possessed heterostructures, can be designed and engineered to be gradient phase alloys with thermal pulses over 350 °C. Atomic diffusion inside the rod structures did not alter the shape of the rods but provided a route to fine-tune their properties. At higher temperatures, the discrepant sublimation behaviours between Au and Ag lead to dealloying of the nanorods. Durative sublimation of the Ag element can continuously tailor the lengths of the nanorods while concentrating the Au composition simultaneously. Especially, nearly pure Au nanocrystals can be obtained with the depletion of Ag by sublimation. These findings give insights into the nanoscale structure and phase behaviours in binary alloys and provide an alternative way to fine-tune their structure, phase, and properties.
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Affiliation(s)
- Long-Bing He
- SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University Nanjing 210096 P. R. China
- Centre for Advanced Materials and Manufacture, Joint Research Institute of Southeast University and Monash University Suzhou 215123 P. R. China
| | - Lei Shangguan
- SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University Nanjing 210096 P. R. China
| | - Ya-Ting Ran
- SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University Nanjing 210096 P. R. China
| | - Chao Zhu
- SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University Nanjing 210096 P. R. China
| | - Zi-Yu Lu
- SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University Nanjing 210096 P. R. China
| | - Jiong-Hao Zhu
- SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University Nanjing 210096 P. R. China
| | - Dao-Jiang Yu
- SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University Nanjing 210096 P. R. China
| | - Cai-Xia Kan
- College of Physics, Nanjing University of Aeronautics and Astronautics No. 29 Jiangjun Road Nanjing 211106 P. R. China
| | - Li-Tao Sun
- SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University Nanjing 210096 P. R. China
- Centre for Advanced Materials and Manufacture, Joint Research Institute of Southeast University and Monash University Suzhou 215123 P. R. China
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Alsawafta M. Anisotropic metallic heterotrimer systems for an ultrahigh plasmonic-based improvement of hyper-Raman scattering signal. NANOTECHNOLOGY 2022; 34:095701. [PMID: 36541509 DOI: 10.1088/1361-6528/aca67c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
An anisotropic metallic trimer is proposed as an active plasmonic substrate for an ultrahigh enhancement in the spectroscopic signal of the hyper-Raman scattering (HRS) process. The suggested three-particle system is composed from non-aligned asymmetric nanoparticles of a cubic shape. The interacting resonators are made of gold material and illuminated by a longitudinally polarized light. The non-alignment condition in the heterotrimer is achieved by shifting the intermediate cube transversely away from the interparticle axis. Optical cross-section, nearfield distribution and charge density are calculated by using the finite-difference time-domain electrodynamic simulation tool. The enhancement factor of the HRS is calculated theoretically from the nearfield intensity associated with the resonance phenomenon of the considered trimer. The extinction profile of the illuminated system exhibits the excitation of two plasmonic modes. A superradiant mode observed in the longer wavelength region which resulted from the in-phase coupling between the plasmonic modes excited in each one of the three resonators. The second mode is a subradiant band emerged from the interference between bright and dark modes. The resonance wavelength of these two modes matches the excitation one and the second-order Stockes condition, respectively. After optimizing the value of both the transverse shift and the gap spacing, the enhancement factor of the HRS can reach as high as a value never reported before of 1 × 1018.
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Affiliation(s)
- Mohammed Alsawafta
- Department of Math and Natural Sciences, College of Arts and Sciences American University of Kuwait, Kuwait
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Enhanced photocatalytic activities of CeO2@ZnO core-shell nanostar particles through delayed electron hole recombination process. Colloids Surf A Physicochem Eng Asp 2022. [DOI: 10.1016/j.colsurfa.2022.128920] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Hu T, Chen Z, Zhang G, Sun N, Zhao P, Liu X, Xie Y. Effect of rhodamine 6G dye molecular interactions on counterintuitive self-assembly of noble metal nanorods. J Colloid Interface Sci 2022; 614:468-477. [PMID: 35108638 DOI: 10.1016/j.jcis.2022.01.113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/09/2022] [Accepted: 01/17/2022] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Self-assembled nanostructures with highly ordered and diversified patterns can be obtained by adding additives that directionally control the interparticle interactions. However, due to the complex non-covalent weak interactions in the self-assembly process, the active mechanism of additives is not fully understood, resulting in the limitation of obtaining the nano-superstructures. The introduction of rhodamine 6G (R6G) enables gold nanorods (GNRs) self-assembled into a counterintuitive tetragonal superlattice, during which the exploration of the influence of R6G molecular interactions on the GNRs self-assembly is of importance. EXPERIMENTS We present the detailed investigations of spacial configuration, binding modes, and aggregated degree of R6G molecule on formation of the tetragonal GNRs superlattices by combining the experimental and simulated results. FINDINGS By analyzing the peak position and peak intensity in the fluorescent spectra of assembled samples and pure R6G samples, H-dimer is verified as the main cause for inducing the tetragonal superstructures. Molecular dynamics simulations reveal that 2-3 H-dimers adsorbed obliquely in a zigzag chain manner on the surface of GNRs is the most stable state of the self-assembly. This work would contribute to a deeper understanding of the complex colloidal nanoparticle self-assemblies and push forward the development of the bottom-up nanoscale superstructures.
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Affiliation(s)
- Tonghua Hu
- School of Physics, Beihang University, Beijing 100191, China
| | - Ziyu Chen
- School of Physics, Beihang University, Beijing 100191, China; Key Laboratory of Intelligent Systems and Equipment Electromagnetic Environment Effect, School of Electronic and Information Engineering, Beihang University, Beijing 100191, China
| | - Guimei Zhang
- School of Physics, Beihang University, Beijing 100191, China
| | - Ningfei Sun
- School of Physics, Beihang University, Beijing 100191, China
| | - Peng Zhao
- School of Physics, Beihang University, Beijing 100191, China
| | - Xiaoduo Liu
- School of Physics, Beihang University, Beijing 100191, China
| | - Yong Xie
- School of Physics, Beihang University, Beijing 100191, China; Key Laboratory of Intelligent Systems and Equipment Electromagnetic Environment Effect, School of Electronic and Information Engineering, Beihang University, Beijing 100191, China.
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Ma D, Chen B, Li Y, Pang X, Fu Q, Xiao Z, Shi Z, Li X, Luo C, Zhou Z, Chen Y, Zhou J. Au@Ag Nanorods-PDMS Wearable Mouthguard as a Visualized Detection Platform for Screening Dental Caries and Periodontal Diseases. Adv Healthc Mater 2022; 11:e2102682. [PMID: 34957703 DOI: 10.1002/adhm.202102682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 12/19/2021] [Indexed: 11/10/2022]
Abstract
The development of easy-to-use, low-cost, and visualized detection platforms for screening human dental caries and periodontal diseases is in urgent demand. In this work, a Au@Ag nanorods-poly(dimethylsiloxane) (Au@Ag NRs-PDMS) wearable mouthguard, which can visualize the tooth lesion sites through the color change of it at the corresponding locations, is presented. The Au@Ag NRs-PDMS composite exhibits a distinct color response to hydrogen sulfide (H2 S) gas generated by bacterial decay at the lesion sites. Moreover, the Au@Ag NRs-PDMS mouthguard is demonstrated to own desired mechanical properties, excellent chemical stability, as well as good biocompatibility, and can accurately locate the lesion sites in human oral cavity. These findings suggest that the mouthguard has the potential to be utilized on a large scale to help people self-monitor their oral health in daily life, and treat oral diseases locally.
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Affiliation(s)
- Dongxu Ma
- Guangdong Provincial Key Laboratory of Sensing Technology and Biomedical Instruments School of Biomedical Engineering Sun Yat‐sen University Guangzhou 510275 China
| | - Baiqi Chen
- Guangdong Provincial Key Laboratory of Sensing Technology and Biomedical Instruments School of Biomedical Engineering Sun Yat‐sen University Guangzhou 510275 China
| | - Yuanfang Li
- Guangdong Provincial Key Laboratory of Sensing Technology and Biomedical Instruments School of Biomedical Engineering Sun Yat‐sen University Guangzhou 510275 China
| | - Xueyuan Pang
- Guangdong Provincial Key Laboratory of Sensing Technology and Biomedical Instruments School of Biomedical Engineering Sun Yat‐sen University Guangzhou 510275 China
| | - Quanying Fu
- Guangdong Provincial Key Laboratory of Sensing Technology and Biomedical Instruments School of Biomedical Engineering Sun Yat‐sen University Guangzhou 510275 China
| | - Zihan Xiao
- Guangdong Provincial Key Laboratory of Sensing Technology and Biomedical Instruments School of Biomedical Engineering Sun Yat‐sen University Guangzhou 510275 China
| | - Zhonghong Shi
- State Key Laboratory of Optoelectronic Materials and Technologies School of Physics Sun Yat‐sen University Guangzhou 510275 China
| | - Xiaolei Li
- Department of Orthodontics Guanghua School of Stomatology Hospital of Stomatology Sun Yat‐sen University Guangzhou 510055 China
| | - Chongdai Luo
- Department of Stomatology Guangzhou Women and Children's Medical Center Guangzhou 510275 China
| | - Zhang‐kai Zhou
- State Key Laboratory of Optoelectronic Materials and Technologies School of Physics Sun Yat‐sen University Guangzhou 510275 China
| | - Yin Chen
- Guangdong Provincial Key Laboratory of Sensing Technology and Biomedical Instruments School of Biomedical Engineering Sun Yat‐sen University Guangzhou 510275 China
| | - Jianhua Zhou
- Guangdong Provincial Key Laboratory of Sensing Technology and Biomedical Instruments School of Biomedical Engineering Sun Yat‐sen University Guangzhou 510275 China
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Hu H, Chen W, Han X, Wang K, Lu P. Plasmonic nanobar-on-mirror antenna with giant local chirality: a new platform for ultrafast chiral single-photon emission. NANOSCALE 2022; 14:2287-2295. [PMID: 35081195 DOI: 10.1039/d1nr05951c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Providing an additional degree of freedom for binary information encoding and nonreciprocal information transmission, chiral single photons have become a new research frontier in quantum optics. Without using complex external conditions (e.g., magnetic field, low temperature), coupling emitters to chiral optical antennas has become a promising strategy to efficiently convert single photons from linear to circular polarization states. For ideal chiral single-photon sources, essential properties such as giant Purcell factor, large degree of circular polarization (DCP), and high collection efficiency are highly demanded. Herein, to meet these combined requirements, we propose an emitter-coupled nanobar-on-mirror antenna platform with significant local chirality acquired from the broken symmetry, as well as the giant Purcell factor owing to its ultrasmall mode volume. An emitter embedded at the corner in the gap exhibits above 3 orders of magnitude enhancement of the chiral spontaneous emission with more than 80% collection efficiency, along with up to 70% DCP. Compatible with a myriad of nanoscale quantum emitters (e.g. transition metal dichalcogenides, color centers, quantum dots, etc.), this platform, not only manifests the potential for realizing ultrafast chiral single-photon generator towards GHz and THz operation speed but also provides versatile testbeds for investigating chiral light-matter interaction at the single-quantum level.
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Affiliation(s)
- Huatian Hu
- Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology, Wuhan 430205, China.
| | - Wen Chen
- Ecole Polytechnique Fédérale de Lausanne, Laboratory of Quantum and Nano-Optics, Lausanne, Switzerland
| | - Xiaobo Han
- Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology, Wuhan 430205, China.
| | - Kai Wang
- Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Peixiang Lu
- Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology, Wuhan 430205, China.
- Wuhan National Laboratory for Optoelectronics and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China.
- Guangdong Intelligent Robotics Institute, Dongguan 523808, China
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Sierra-Martin B, Fernandez-Barbero A. Particles and nanovoids for plasmonics. Adv Colloid Interface Sci 2021; 290:102394. [PMID: 33711675 DOI: 10.1016/j.cis.2021.102394] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 02/24/2021] [Accepted: 02/25/2021] [Indexed: 12/19/2022]
Abstract
This article reviews and compares the optical properties of metallic nanoparticles and nanovoids, which have received great attention due to their ability to generate and control plasmon resonances. These systems are capable of concentrating and manipulating the fields at nanometer scale, being very attractive as building blocks for emerging applications. Metal particles and nanovoids present different plasmonics modes, strongly dependent on the size, shape and nature of the metal and dielectric. Specific geometrical features, as the presence of rims, make the nanovoids very promising structures to design exotic band spectra because of the coupling between different resonant modes.
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