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Mandal S, Gupta AK, Konečná A, Shirato N, Hachtel JA, Sachan R. Creation of Multi-Principal Element Alloy NiCoCr Nanostructures via Nanosecond Laser-Induced Dewetting. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2309574. [PMID: 38556631 DOI: 10.1002/smll.202309574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 02/06/2024] [Indexed: 04/02/2024]
Abstract
The multi-principal element alloy nanoparticles (MPEA NPs), a new class of nanomaterials, present a highly rewarding opportunity to explore new or vastly different functional properties than the traditional mono/bi/multimetallic nanostructures due to their unique characteristics of atomic-level homogeneous mixing of constituent elements in the nanoconfinements. Here, the successful creation of NiCoCr nanoparticles, a well-known MPEA system is reported, using ultrafast nanosecond laser-induced dewetting of alloy thin films. Nanoparticle formation occurs by spontaneously breaking the energetically unstable thin films in a melt state under laser-induced hydrodynamic instability and subsequently accumulating in a droplet shape via surface energy minimization. While NiCoCr alloy shows a stark contrast in physical properties compared to individual metallic constituents, i.e., Ni, Co, and Cr, yet the transient nature of the laser-driven process facilitates a homogeneous distribution of the constituents (Ni, Co, and Cr) in the nanoparticles. Using high-resolution chemical analysis and scanning nanodiffraction, the environmental stability and grain arrangement in the nanoparticles are further investigated. Thermal transport simulations reveal that the ultrashort (≈100 ns) melt-state lifetime of NiCoCr during the dewetting event helps retain the constituent elements in a single-phase solid solution with homogenous distribution and opens the pathway to create the unique MPEA nanoparticles with laser-induced dewetting process.
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Affiliation(s)
- Soumya Mandal
- Department of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Ashish Kumar Gupta
- Department of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Andrea Konečná
- Central European Institute of Technology, Brno University of Technology, Brno, 61200, Czech Republic
- Institute of Physical Engineering, Brno University of Technology, Brno, 616 69, Czech Republic
| | - Nozomi Shirato
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, IL, 60439, USA
| | - Jordan A Hachtel
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Ritesh Sachan
- Department of Mechanical and Aerospace Engineering, Oklahoma State University, Stillwater, OK, 74078, USA
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2
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Hizi A, Forster GD, Ferrando R, Garreau Y, Coati A, Andreazza-Vignolle C, Andreazza P. Combined atomistic simulations to explore metastability and substrate effects in Ag-Co nanoalloy systems. Faraday Discuss 2023; 242:35-51. [PMID: 36349781 DOI: 10.1039/d2fd00114d] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The Ag/Co nanoalloy system is a model system situated energetically at the limit of stability of the core-shell chemical ordering with respect to a simple phase separation behavior. This makes the system highly susceptible to effects of the environment, such as interaction with a substrate. However, kinetic effects may also be exploited by careful atom-by-atom particle growth that allows to lock in certain out-of-equilibrium configurations, such as off-center, quasi-Janus and even Janus type particles. In this contribution, we explore to what extent out-of-equilibrium structures are due to kinetic effects and the influence of the interaction of the particles with an amorphous carbon substrate by a joint experimental and molecular dynamics study. The simulation set up performed at 300 K and 600 K mimicks the experimental growth process. The substrate deforms the particles, but has also an ordering effect on particle orientation and particle structure. In the case of growth of Ag on Co seeds, particles assume close to equilibrium quasi-Janus structures, while for the deposition of Co on Ag seeds, highly out-of-equilibrium structures with several subsurface Co clusters are obtained.
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Affiliation(s)
- Abir Hizi
- Interfaces, Confinement, Matériaux et Nanostructures (ICMN), Université d'Orléans, CNRS, Orléans, France.
| | - Georg Daniel Forster
- Interfaces, Confinement, Matériaux et Nanostructures (ICMN), Université d'Orléans, CNRS, Orléans, France.
| | | | | | | | | | - Pascal Andreazza
- Interfaces, Confinement, Matériaux et Nanostructures (ICMN), Université d'Orléans, CNRS, Orléans, France.
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The Effect of Co Content and Annealing Temperatures on the Resistivity in Ag-Co Films. NANOMATERIALS 2022; 12:nano12132297. [PMID: 35808132 PMCID: PMC9268058 DOI: 10.3390/nano12132297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/15/2022] [Accepted: 06/27/2022] [Indexed: 11/16/2022]
Abstract
Ag-Co films with ultra-high resistivity were prepared on polyimide by magnetron sputtering. The effect of Co content and annealing temperatures on the resistivity and microstructure of Ag-Co films has been thoroughly investigated and the relation between resistivity and microstructure has been discussed. Results show that thicker Ag-Co films without annealing present lower resistivity due to better crystallinity. However, thin Ag-Co films (≤21 nm) annealed at 360 °C present ultra-high film resistivity because of the formation of diffusion pits on the film surface which blocks the transmission of electrons in films to increase film resistivity. Inversely, the resistivity of thick Ag-Co films (≥45 nm) annealed at 360 °C is much less than that annealed at lower than 260 °C owing to no diffusion pits. Furthermore, the addition of Co inhibits the growth of Ag grains and limits the migration of electrons in Ag-Co films further, also resulting in the increase of Ag-Co films’ resistivity.
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Garfinkel DA, Tang N, Pakeltis G, Emery R, Ivanov IN, Gilbert DA, Rack PD. Magnetic and Optical Properties of Au-Co Solid Solution and Phase-Separated Thin Films and Nanoparticles. ACS APPLIED MATERIALS & INTERFACES 2022; 14:15047-15058. [PMID: 35333040 DOI: 10.1021/acsami.2c02028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The chemical composition and morphology of AuxCo1-x thin films and nanoparticles are controlled via a combination of cosputtering, pulsed laser-induced dewetting (PLiD), and annealing, leading to tunable magnetic and optical properties. Regardless of chemical composition, the as-deposited thin films and as-PLiD nanoparticles are found to possess a face-centered cubic (FCC) AuxCo1-x solid-solution crystal structure. Annealing results in large phase-separated grains of Au and Co in both the thin films and nanostructures for all chemical compositions. The magnetic and optical properties are characterized via vibrating sample magnetometry (VSM), ellipsometry, optical transmission spectroscopy, and electron energy loss spectroscopy (EELS). Despite the exceptionally high magnetic anisotropy inherent to Co, the presence of sufficient Au (72 atom %) in the AuxCo1-x solid solution results in superparamagnetic thin films. Among the as-PLiD nanoparticle samples, an increased Co composition leads to a departure from traditional ferromagnetism in favor of wasp-waisted hysteresis caused by magnetic vortices. Phase separation resulting from annealing leads to ferromagnetism for all compositions in both the thin films and nanoparticles. The optical properties of AuxCo1-x nanostructures are also largely influenced by the chemical morphology, where the AuxCo1-x intermixed solid solution has significantly damped plasmonic performance relative to pure Au and comparable to pure Co. Phase separation greatly enhances the quality factor, optical absorption, and electron energy loss spectroscopy (EELS) signatures. The enhancement of the localized surface plasmon resonances (LSPRs) scales with the reduction in Co composition, despite EELS evidence that excitation of the Co portions of a nanoparticle can provide a similar, and in some instances enhanced, LSPR resonance compared to Au. This behavior, however, is seemingly limited to the LSPR dipole mode, while higher-order modes are greatly damped by a Co aloof position. This observed magneto-plasmonic functionality and tunability could be applicable in biomedicine, namely, cancer therapeutics.
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Affiliation(s)
- David A Garfinkel
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Nan Tang
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Grace Pakeltis
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Reece Emery
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Ilia N Ivanov
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Dustin A Gilbert
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Philip D Rack
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
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5
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Andreazza P, Lemoine A, Coati A, Nelli D, Ferrando R, Garreau Y, Creuze J, Andreazza-Vignolle C. From metastability to equilibrium during the sequential growth of Co-Ag supported clusters: a real-time investigation. NANOSCALE 2021; 13:6096-6104. [PMID: 33683240 DOI: 10.1039/d0nr08862e] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Atomic motions and morphological evolution of growing Co-Ag nanoparticles are followed in situ and in real time, by wide and small angle X-ray scattering obtained simultaneously in grazing incidence geometry (GISAXS and GIWAXS), in single or multi-wavelength anomalous modes. The structural analysis of the experimental data is performed with the aid of equilibrium Monte Carlo simulations and of molecular-dynamics simulations of nanoparticle growth. Growth is performed by depositing Co atoms above preformed Ag nanoparticles. This growth procedure is strongly out of equilibrium, because Ag tends to surface segregation, and generates complex growth sequences. The real time analysis of the growth allows to follow the nanoparticle evolution pathways almost atom-by-atom, determining the key mechanisms during Co deposition: starting with the incorporation of Co atoms in sub-surface positions, to the off-center Co domain formation, then by which the nanoparticles finally approach their equilibrium quasi-Janus then core-shell structures.
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Affiliation(s)
- P Andreazza
- Interfaces, Confinement, Matériaux et Nanostructures, ICMN, Université d'Orléans, CNRS, Orléans, France.
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Diez JA, González AG, Garfinkel DA, Rack PD, McKeown JT, Kondic L. Simultaneous Decomposition and Dewetting of Nanoscale Alloys: A Comparison of Experiment and Theory. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:2575-2585. [PMID: 33587633 DOI: 10.1021/acs.langmuir.0c02964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We consider the coupled process of phase separation and dewetting of metal alloys of nanoscale thickness deposited on solid substrates. The experiments involve applying nanosecond laser pulses that melt the Ag40Ni60 alloy films in two setups: either on thin supporting membranes or on bulk substrates. These two setups allow for extracting both temporal and spatial scales on which the considered processes occur. The theoretical model involves a longwave version of the Cahn-Hilliard formulation used to describe spinodal decomposition, coupled with an asymptotically consistent longwave-based description of dewetting that occurs due to destabilizing interactions between the alloy and the substrate, modeled using the disjoining pressure approach. Careful modeling, combined with linear stability analysis and fully nonlinear simulations, leads to results consistent with the experiments. In particular, we find that the two instability mechanisms occur concurrently, with the phase separation occurring faster and on shorter temporal scales. The modeling results show a strong influence of the temperature dependence of relevant material properties, implying that such a dependence is crucial for the understanding of the experimental findings. The agreement between theory and experiment suggests the utility of the proposed theoretical approach in helping to develop further experiments directed toward formation of metallic alloy nanoparticles of desired properties.
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Affiliation(s)
- Javier A Diez
- CIFICEN-CONICET-CICPBA, Instituto de Física Arroyo Seco, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, 7000 Tandil, Argentina
| | - Alejandro G González
- CIFICEN-CONICET-CICPBA, Instituto de Física Arroyo Seco, Universidad Nacional del Centro de la Provincia de Buenos Aires, Pinto 399, 7000 Tandil, Argentina
| | - David A Garfinkel
- Department of Materials Science & Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
- Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Philip D Rack
- Department of Materials Science & Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
- Center for Nanophase Materials Science, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Joseph T McKeown
- Materials Science Division, Lawrence Livermore National Laboratory, Livermore, California 94550, United States
| | - Lou Kondic
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey 07102, United States
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7
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Facile synthesis by laser ablation in liquid of nonequilibrium cobalt-silver nanoparticles with magnetic and plasmonic properties. J Colloid Interface Sci 2021; 585:267-275. [DOI: 10.1016/j.jcis.2020.11.089] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/16/2020] [Accepted: 11/23/2020] [Indexed: 12/13/2022]
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8
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Garfinkel D, Pakeltis G, Tang N, Ivanov IN, Fowlkes JD, Gilbert DA, Rack PD. Optical and Magnetic Properties of Ag-Ni Bimetallic Nanoparticles Assembled via Pulsed Laser-Induced Dewetting. ACS OMEGA 2020; 5:19285-19292. [PMID: 32775932 PMCID: PMC7409265 DOI: 10.1021/acsomega.0c02894] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 07/08/2020] [Indexed: 05/20/2023]
Abstract
Pulsed laser-induced dewetting (PLiD) of Ag0.5Ni0.5 thin films results in phase-separated bimetallic nanoparticles with size distributions that depend on the initial thin film thickness. Co-sputtering of Ag and Ni is used to generate the as-deposited (AD) nanogranular supersaturated thin films. The magnetic and optical properties of the AD thin films and PLiD nanoparticles are characterized using a vibrating sample magnetometer, optical absorption spectroscopy, and electron energy loss spectroscopy (EELS). Magnetic measurements demonstrate that Ag0.5Ni0.5 nanoparticles are ferromagnetic at room temperature when the nanoparticle diameters are >20 nm and superparamagnetic <20 nm. Optical measurements show that all nanoparticle size distributions possess a local surface plasmon resonance (LSPR) peak that red-shifts with increasing diameter. Following PLiD, a Janus nanoparticle morphology is observed in scanning transmission electron microscopy, and low-loss EELS reveals size-dependent Ag and Ni LSPR dipole modes, while higher order modes appear only in the Ag hemisphere. PLiD of Ag-Ni thin films is shown to be a viable technique to generate bimetallic nanoparticles with both magnetic and plasmonic functionality.
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Affiliation(s)
- David
A. Garfinkel
- Department
of Materials Science and Engineering, University
of Tennessee, Knoxville, Tennessee 37996, United States
| | - Grace Pakeltis
- Department
of Materials Science and Engineering, University
of Tennessee, Knoxville, Tennessee 37996, United States
| | - Nan Tang
- Department
of Materials Science and Engineering, University
of Tennessee, Knoxville, Tennessee 37996, United States
| | - Ilia N. Ivanov
- Center
for Nanophase Materials Sciences, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Jason D. Fowlkes
- Department
of Materials Science and Engineering, University
of Tennessee, Knoxville, Tennessee 37996, United States
- Center
for Nanophase Materials Sciences, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Dustin A. Gilbert
- Department
of Materials Science and Engineering, University
of Tennessee, Knoxville, Tennessee 37996, United States
| | - Philip D. Rack
- Department
of Materials Science and Engineering, University
of Tennessee, Knoxville, Tennessee 37996, United States
- Center
for Nanophase Materials Sciences, Oak Ridge
National Laboratory, Oak Ridge, Tennessee 37831, United States
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9
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Chen D, Ning P, Zhang Y, Jing J, Zhang M, Zhang L, Huang J, He X, Fu T, Song Z, He G, Qian D, Zhu X. Ta@Ag Porous Array with High Stability and Biocompatibility for SERS Sensing of Bacteria. ACS APPLIED MATERIALS & INTERFACES 2020; 12:20138-20144. [PMID: 32191424 DOI: 10.1021/acsami.0c03630] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The reliable sensing of bacteria by surface-enhanced Raman scattering (SERS) technology necessitates a rational design of a substrate with high sensitivity, stability, and minimal invasion. Hence, a bimetallic Ta@Ag film with a porous array is developed by the magnetron sputtering technique and the structure could be controlled by a Ta dopant. A porous array connected by ligaments with compact granular nanoprotrusions is a fascinating substrate for SERS sensing. It makes steady SERS signals even in harsh chemical environments due to its high structural and chemical stability. The configuration of binary Ta@Ag has higher surface free energy than that of pure Ag, and the strong bactericidal activity of Ag is suppressed efficiently. Using E. coli as a model pathogen, the Ta@Ag porous film could maintain the long-term survival rate of E. coli up to 95% and a limit of SERS detection of E. coli down to 102 CFU/mL, which is measured by the standard colony-counting method. In sum, this work provides a promising strategy to fabricate a corrosion-resistant and biocompatible bimetallic Ta@Ag film with a porous array for the SERS sensing of microbial cells.
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Affiliation(s)
- Dongzhen Chen
- School of Materials Science & Engineering, Xi'an Polytechnic University, Xi'an, Shaanxi 710048, P. R. China
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
| | - Pan Ning
- Key Laboratory of Biomedical Information Engineering of Education Ministry, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
| | - Yu Zhang
- The Key Laboratory of Ministry of Education, Xi'an Jiaotong University, Xi'an 710049, P. R. China
| | - Jinyu Jing
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
| | - Meng Zhang
- Department of Neurology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P. R. China
| | - Liang Zhang
- School of Materials Science & Engineering, Xi'an Polytechnic University, Xi'an, Shaanxi 710048, P. R. China
| | - Jian Huang
- School of Chemistry and Chemical Engineering, Xi'an Shiyou University, Xi'an 710065, P. R. China
| | - Xinhai He
- School of Materials Science & Engineering, Xi'an Polytechnic University, Xi'an, Shaanxi 710048, P. R. China
| | - Tao Fu
- Key Laboratory of Biomedical Information Engineering of Education Ministry, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
| | - Zhongxiao Song
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
| | - Guangyu He
- Science and Technology on Plasma Dynamics Laboratory, Air Force Engineering University, Xi'an 710038, China
| | - Dan Qian
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
| | - Xiaodong Zhu
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, Shaanxi 710049, P. R. China
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10
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Surface, Interface, and Temperature Effects on the Phase Separation and Nanoparticle Self Assembly of Bi-Metallic Ni0.5Ag0.5: A Molecular Dynamics Study. NANOMATERIALS 2019; 9:nano9071040. [PMID: 31330888 PMCID: PMC6669487 DOI: 10.3390/nano9071040] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/10/2019] [Accepted: 07/19/2019] [Indexed: 11/16/2022]
Abstract
Classical molecular dynamics (MD) simulations were used to investigate how free surfaces, as well as supporting substrates, affect phase separation in a NiAg alloy. Bulk samples, droplets, and droplets deposited on a graphene substrate were investigated at temperatures that spanned regions of interest in the bulk NiAg phase diagram, i.e., miscible and immiscible liquid, liquid-crystal, and crystal-crystal regions. Using MD simulations to cool down a bulk sample from 3000 K to 800 K, it was found that phase separation below 2400 K takes place in agreement with the phase diagram. When free surface effects were introduced, phase separation was accompanied by a core-shell transformation: spherical droplets created from the bulk samples became core-shell nanoparticles with a shell made mostly of Ag atoms and a core made of Ni atoms. When such droplets were deposited on a graphene substrate, the phase separation was accompanied by Ni layering at the graphene interface and Ag at the vacuum interface. Thus, it should be possible to create NiAg core-shell and layer-like nanostructures by quenching liquid NiAg samples on tailored substrates. Furthermore, interesting bimetallic nanoparticle morphologies might be tuned via control of the surface and interface energies and chemical instabilities of the system.
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11
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Sandireddy VP, Koirala KP, Taz H, Kalyanaraman R. Thermal and Plasmonic Stabilization of Silver Nanostructures Using a Bilayer Anchoring Technique. ACS APPLIED MATERIALS & INTERFACES 2018; 10:33630-33639. [PMID: 30191708 DOI: 10.1021/acsami.8b10386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In this work, we demonstrate how to suppress the shape instability of silver (Ag) nanotriangular pyramids following high-temperature annealing without a coating or encapsulation, thus producing a more stable optical plasmonic system. Nanosphere lithography (NSL) was used to fabricate large-area arrays of nanotriangular pyramids of Ag on glass substrates. By using a combination of morphology and spectroscopic studies it was found that exposure of this system to high temperatures of 473 K and beyond in air led to a rapid change in nanostructure shape, and thus, the surface area, with a substantial change to the original plasmonic character. On the other hand, NSL nanotriangular pyramids made from bilayers of Ag on Co or Co on Ag showed much smaller changes in shape and area following annealing up to 573 K in air. In the case of pure Ag, the NSL nanotriangular pyramid changed into a more spherical shape with an overall decrease of ∼24% in its surface area following annealing at 573 K. This lead to a large blue shift of over ∼287 nm or ∼39% in the location of the dipolar plasmonic resonance. On the other hand, the triangular shape of Ag was retained in both the metal bilayer cases, with much smaller area changes of ∼10 and ∼9%, for the Ag deposit when on Co and when under Co, respectively. Consequently, the plasmonic shifts were substantially smaller, of ∼65 nm or about 9%, in these bilayer systems. The mechanism for this stabilization was attributed to the higher surface energy of Co and much lower diffusivity of Co as well as Ag on Co that resulted in an anchoring of the Ag shape to its original state. The plasmonic quality factor for the bimetal NSL nanotriangular pyramids also showed substantially improved stability over pure Ag, further indicating that this anchoring approach is a viable pathway to produce pristine Ag surfaces for high-temperature plasmonic applications.
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Wu Y, Li G, Camden JP. Probing Nanoparticle Plasmons with Electron Energy Loss Spectroscopy. Chem Rev 2017; 118:2994-3031. [DOI: 10.1021/acs.chemrev.7b00354] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Yueying Wu
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Guoliang Li
- Center for Electron Microscopy, Institute for New Energy Materials and Low-Carbon Technologies, School of Materials Science and Engineering, Tianjin University of Technology, Tianjin 300384, China
| | - Jon P. Camden
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
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13
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Experimental Analysis on the Molten-Phase Dewetting Characteristics of AuPd Alloy Films on Topographically-Structured Substrates. METALS 2017. [DOI: 10.3390/met7090327] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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14
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Thompson KJ, Harley CM, Barthel GM, Sanders MA, Mesce KA. Plasmon resonance and the imaging of metal-impregnated neurons with the laser scanning confocal microscope. eLife 2015; 4. [PMID: 26670545 PMCID: PMC4718721 DOI: 10.7554/elife.09388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 11/04/2015] [Indexed: 11/13/2022] Open
Abstract
The staining of neurons with silver began in the 1800s, but until now the great resolving power of the laser scanning confocal microscope has not been utilized to capture the in-focus and three-dimensional cytoarchitecture of metal-impregnated cells. Here, we demonstrate how spectral confocal microscopy, typically reserved for fluorescent imaging, can be used to visualize metal-labeled tissues. This imaging does not involve the reflectance of metal particles, but rather the excitation of silver (or gold) nanoparticles and their putative surface plasmon resonance. To induce such resonance, silver or gold particles were excited with visible-wavelength laser lines (561 or 640 nm), and the maximal emission signal was collected at a shorter wavelength (i.e., higher energy state). Because the surface plasmon resonances of noble metal nanoparticles offer a superior optical signal and do not photobleach, our novel protocol holds enormous promise of a rebirth and further development of silver- and gold-based cell labeling protocols.
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Affiliation(s)
- Karen J Thompson
- Department of Biology, Neuroscience Program, Agnes Scott College, Decatur, United States
| | - Cynthia M Harley
- Department of Entomology, Graduate Program in Neuroscience, University of Minnesota, Saint Paul, United States
| | - Grant M Barthel
- University Imaging Centers Core Facility, University of Minnesota, Saint Paul, United States
| | - Mark A Sanders
- University Imaging Centers Core Facility, University of Minnesota, Saint Paul, United States
| | - Karen A Mesce
- Department of Entomology, Graduate Program in Neuroscience, University of Minnesota, Saint Paul, United States
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15
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Weber de Menezes J, Thesing A, Valsecchi C, Armas LEG, Brolo AG. Improving the performance of gold nanohole array biosensors by controlling the optical collimation conditions. APPLIED OPTICS 2015; 54:6502-6507. [PMID: 26367835 DOI: 10.1364/ao.54.006502] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
An experimental investigation on how the bulk and surface sensitivities of gold nanohole arrays fabricated by interference lithography affect the degree of white light beam collimation is presented. The optical transmission response of nanohole arrays has been recorded by focused and collimated beam transmission spectra. The results show that both the bulk and surface sensitivities for the collimated case are much larger than for the focused case. In particular, the shape of the spectra was dependent on the degree of beam collimation. The results showed that improved sensing performance (around 3.5 times) and higher figure of merit (around 4.4 times) can be obtained by simply adjusting the incident/collection experimental conditions in transmission measurements.
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16
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Malasi A, Sachan R, Ramos V, Garcia H, Duscher G, Kalyanaraman R. Localized surface plasmon sensing based investigation of nanoscale metal oxidation kinetics. NANOTECHNOLOGY 2015; 26:205701. [PMID: 25913244 DOI: 10.1088/0957-4484/26/20/205701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The localized surface plasmon resonance (LSPR) of nanoparticles can be a powerful and sensitive probe of chemical changes in nanoscale volumes. Here we have used the LSPR of silver (Ag) to study the oxidation kinetics of nanoscopic volumes of cobalt (Co) metal. Bimetal nanoparticles of the immiscible Co-Ag system prepared by pulsed laser dewetting were aged in ambient air and the resulting changes to the LSPR signal and bandwidth were used to probe the oxidation kinetics. Co was found to preferentially oxidize first. This resulted in a significant enhancement by a factor of 8 or more in the lifetime of stable Ag plasmons over that of pure Ag. Theoretical modeling based on optical mean field approximation was able to predict the oxidation lifetimes and could help design stable Ag-based plasmonic nanoparticles for sensing applications.
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Affiliation(s)
- A Malasi
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, Tennessee, 37996, USA
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Yadavali S, Sachan R, Dyck O, Kalyanaraman R. DC electric field induced phase array self-assembly of Au nanoparticles. NANOTECHNOLOGY 2014; 25:465301. [PMID: 25355725 DOI: 10.1088/0957-4484/25/46/465301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this work we report the discovery of phase array self-assembly, a new way to spontaneously make periodic arrangements of metal nanoparticles. An initially random arrangement of gold (Au) or silver (Ag) nanoparticles on SiO2/Si substrates was irradiated with linearly polarized (P) laser light in the presence of a dc electric (E) field applied to the insulating substrate. For E fields parallel to the laser polarization (E||P), the resulting periodic ordering was single-crystal like with extremely low defect density and covered large macroscopic areas. The E field appears to be modifying the phase between radiation scattered by the individual nanoparticles thus leading to enhanced interference effects. While phase array behavior is widely known in antenna technology, this is the first evidence that it can also aid in nanoscale self-assembly. These results provide a simple way to produce periodic metal nanoparticles over large areas.
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Affiliation(s)
- S Yadavali
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA
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Sachan R, Malasi A, Ge J, Yadavali S, Krishna H, Gangopadhyay A, Garcia H, Duscher G, Kalyanaraman R. Ferroplasmons: intense localized surface plasmons in metal-ferromagnetic nanoparticles. ACS NANO 2014; 8:9790-8. [PMID: 25068441 DOI: 10.1021/nn5031719] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Interaction of photons with matter at length scales far below their wavelengths has given rise to many novel phenomena, including localized surface plasmon resonance (LSPR). However, LSPR with narrow bandwidth (BW) is observed only in a select few noble metals, and ferromagnets are not among them. Here, we report the discovery of LSPR in ferromagnetic Co and CoFe alloy (8% Fe) in contact with Ag in the form of bimetallic nanoparticles prepared by pulsed laser dewetting. These plasmons in metal-ferromagnetic nanostructures, or ferroplasmons (FP) for short, are in the visible spectrum with comparable intensity and BW to those of the LSPRs from the Ag regions. This finding was enabled by electron energy-loss mapping across individual nanoparticles in a monochromated scanning transmission electron microscope. The appearance of the FP is likely due to plasmonic interaction between the contacting Ag and Co nanoparticles. Since there is no previous evidence for materials that simultaneously show ferromagnetism and such intense LSPRs, this discovery may lead to the design of improved plasmonic materials and applications. It also demonstrates that materials with interesting plasmonic properties can be synthesized using bimetallic nanostructures in contact with each other.
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Affiliation(s)
- Ritesh Sachan
- Department of Materials Science and Engineering, University of Tennessee , Knoxville, Tennessee 37996, United States
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Roberts NA, Fowlkes JD, Mahady K, Afkhami S, Kondic L, Rack PD. Directed assembly of one- and two-dimensional nanoparticle arrays from pulsed laser induced dewetting of square waveforms. ACS APPLIED MATERIALS & INTERFACES 2013; 5:4450-4456. [PMID: 23607517 DOI: 10.1021/am400925h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The directed assembly of arrayed nanoparticles is demonstrated by dictating the flow of a liquid phase filament on the nanosecond time scale. Results for the assembly of Ni nanoparticles on SiO2 are presented. Previously, we have implemented a sinusoidal perturbation on the edge of a solid phase Ni, thin film strip to tailor nanoparticle assembly. Here, a nonlinear square waveform is explored. This waveform made it possible to expand the range of nanoparticle spacing-radius combinations attainable, which is otherwise limited by the underlying Rayleigh-Plateau type of instability. Simulations of full Navier-Stokes equations based on volume of fluid method were implemented to gain further insight regarding the nature of instability mechanism leading to particle formation in experiments.
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Affiliation(s)
- Nicholas A Roberts
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
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Sachan R, Ramos V, Malasi A, Yadavali S, Bartley B, Garcia H, Duscher G, Kalyanaraman R. Oxidation-resistant silver nanostructures for ultrastable plasmonic applications. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:2045-2050. [PMID: 23417783 DOI: 10.1002/adma.201204920] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Indexed: 06/01/2023]
Abstract
Reduced degradation (oxidation) of silver nanoparticles (NPs) is achieved by contacting Ag with immiscible Co NPs. The relative decay of the plasmon peak (plot) shows that pure Ag NPs (blue dashed curve) decay by 25% in ca 20 days, whereas AgCo NPs last about 10 times longer, requiring nearly five months for a similar decay (red solid curve). The TEM images for both Ag and AgCo were taken after 50 days of storage under ambient conditions.
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Affiliation(s)
- R Sachan
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA
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Oh YJ, Kim JH, Thompson CV, Ross CA. Templated assembly of Co-Pt nanoparticles via thermal and laser-induced dewetting of bilayer metal films. NANOSCALE 2013; 5:401-407. [PMID: 23175433 DOI: 10.1039/c2nr32932h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Templated dewetting of a Co/Pt metal bilayer film on a topographic substrate was used to assemble arrays of Co-Pt alloy nanoparticles, with highly uniform particle size, shape and notably composition compared to nanoparticles formed on an untemplated substrate. Solid-state and liquid-state dewetting processes, using furnace annealing and laser irradiation respectively, were compared. Liquid state dewetting produced more uniform, conformal nanoparticles but they had a polycrystalline disordered fcc structure and relatively low magnetic coercivity. In contrast, solid state dewetting enabled formation of magnetically hard, ordered L1(0) Co-Pt single-crystal particles with coercivity >12 kOe. Furnace annealing converted the nanoparticles formed by liquid state dewetting into the L1(0) phase.
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Affiliation(s)
- Yong-Jun Oh
- Department of Advanced Materials Science and Engineering, Hanbat National University, 125, Dongseo-daero, Yuseong-gu, Daejeon 305-719, Korea.
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