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Fabrication of conducting polymer-gold nanoparticles film on electrodes using monolayer protected gold nanoparticles and its electrocatalytic application. Electrochim Acta 2011. [DOI: 10.1016/j.electacta.2011.06.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Li H, Liew KM, Zhang XQ, Zhang JX, Liu XF, Bian XF. Electron-Conduction Properties of Fe−Al Alloy Nanowires. J Phys Chem B 2008; 112:15588-95. [DOI: 10.1021/jp806640u] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- H. Li
- Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, School of Materials Science and Engineering, Shandong University, Department of Building and Construction, City University of Hong Kong, Kowloon, Hong Kong
| | - K. M. Liew
- Department of Building and Construction, City University of Hong Kong, Kowloon, Hong Kong
| | - X. Q. Zhang
- Physics Department, Ocean University of China, Qingdao, China
| | - J. X. Zhang
- Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, School of Materials Science and Engineering, Shandong University, Shandong, China
| | - X. F. Liu
- Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, School of Materials Science and Engineering, Shandong University, Shandong, China
| | - X. F. Bian
- Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, School of Materials Science and Engineering, Shandong University, Shandong, China
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Kannan P, Abraham John S. Synthesis of mercaptothiadiazole-functionalized gold nanoparticles and their self-assembly on Au substrates. NANOTECHNOLOGY 2008; 19:085602. [PMID: 21730726 DOI: 10.1088/0957-4484/19/8/085602] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Gold nanoparticles (AuNPs) stabilized with mercaptothiadiazole ligands, 2,5-dimercapto-1,3,4-thiadiazole (DMT), 5-amino-2-mercapto-1,3,4-thiadiazole (AMT) and 5-methyl-2-mercapto-1,3,4-thiadiazole (MMT), were prepared by the reaction of the respective ligands with HAuCl(4) and NaBH(4) in an aqueous medium. TEM images show that the average size of AuNPs was 6.5 ± 0.5 nm, irrespective of the capping ligands. The colloidal solution of both DMT-capped AuNPs (DMT-AuNPs) and AMT-capped AuNPs (AMT-AuNPs) were highly stable for several months. However, several changes were noticed for MMT-capped AuNPs (MMT-AuNPs) after 2 h from its formation. The SPR band intensity at 518 nm decreases and the narrow SPR absorption band slowly changes into a flat absorption pattern with a broad peak from 518 to 1000 nm which was accompanied by a colour change of the solution from red to purple and then blue and thereafter unchanged. The TEM image of MMT-AuNPs after 96 h shows that most of the spherical shape of the AuNPs assembled to form a nanowire-like structure. The observed changes may be due to the absence of a strong stabilizing force on the surface of the MMT-AuNPs. The amino and thiolate groups on the surface of the AMT-AuNPs and DMT-AuNPs, respectively, were directly self-assembled on Au electrodes. They exhibit excellent electrocatalytic activity towards the oxidation of AA by enhancing its oxidation current twice in addition to more than 200 mV negative shift in the oxidation potential in contrast to bare Au electrode.
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Affiliation(s)
- Palanisamy Kannan
- Department of Chemistry, Gandhigram Rural University, Dindigul, Gandhigram 624 302, India
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Sainsbury T, Stolarczyk J, Fitzmaurice D. An experimental and theoretical study of the self-assembly of gold nanoparticles at the surface of functionalized multiwalled carbon nanotubes. J Phys Chem B 2007; 109:16310-25. [PMID: 16853074 DOI: 10.1021/jp051224c] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This paper reports the findings of a detailed study of the self-assembly of gold nanoparticles at the surface of carbon nanotubes (CNTs). The study included the development of a predictive model for the interactions (charge transfer, van der Waals, osmotic, elastic, nonelastic, and covalent) between tetraoctylammonium bromide-stabilized (TOAB) gold nanoparticles and alkyl- and alkylthiol-modified multiwalled carbon nanotubes (MWCNTs). It also included the measurement of the coverage of gold nanoparticles at the surface of the above MWCNTs as a function of increasing alkyl chain length. One key finding is that it is possible to predict with a high degree of accuracy using the above model the measured coverage of gold nanoparticles adsorbed, either noncovalently or covalently, at the surface of a MWCNT. Another key finding is that, as predicted, under well-defined conditions the measured coverage of nanoparticles is very sensitive to the nature of the modified CNT surface and the contiguous environment, providing valuable insights that will underpin the rational design of functional nanoscale devices assembled from nanoparticle and CNT building blocks.
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Affiliation(s)
- Toby Sainsbury
- Department of Chemistry, University College Dublin, Belfield, Dublin 4, Ireland
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Electron transport through alkanethiolate films decorated with monolayer protected gold clusters. Electrochim Acta 2006. [DOI: 10.1016/j.electacta.2005.03.091] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Chaki NK, Kakade B, Vijayamohanan KP, Singh P, Dharmadhikari CV. Investigation of interparticle interactions of larger (4.63 nm) monolayer protected gold clusters during quantized double layer charging. Phys Chem Chem Phys 2006; 8:1837-44. [PMID: 16633670 DOI: 10.1039/b516650k] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this article, the effect of interparticle interactions of 4.63 nm sized monolayer protected gold clusters (Au MPCs) during quantized double layer (QDL) charging has been investigated using electrochemical techniques. Voltammetry and scanning tunneling microscopy have been used to compare their electron transfer behavior. Furthermore, since the QDL process is diffusion controlled, the diffusion coefficient values have been estimated at various charge steps using two independent electroanalytical techniques, viz. chronoamperometry and impedance. These results show that higher core charge facilitates higher diffusion coefficient values, and indicate that repulsive interactions dominate for charged MPCs compared to those of its neutral analogue, which are mainly attractive in nature. Additionally, the electron transfer rate constants at various charge steps have been estimated from the impedance results, showing comparatively faster electron transfer rate at higher charge states.
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Affiliation(s)
- Nirmalya Kumar Chaki
- Physical and Materials Chemistry Division, National Chemical Laboratory, Pune 411008, India
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York RL, Nacionales D, Slowinski K. Electrical resistivity of monolayers and bilayers of alkanethiols in tunnel junction with gate electrode. Chem Phys 2005. [DOI: 10.1016/j.chemphys.2005.05.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Yang N, Aoki K. Molecular Numbers in Core and Shell: Structural Dependence of Reactivity of Alkylcarboxylate-Stabilized Silver Nanoparticles. J Phys Chem B 2005; 109:23911-7. [PMID: 16375377 DOI: 10.1021/jp052173m] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Spectroscopic, chemical, thermal, and voltammetric analyses on six kinds of alkylcarboxylate-stabilized silver nanoparticles 4.7 nm in diameter were carried out with an aim to reveal the effect of alkylcarboxylates on the optical, thermal, geometric, and electrochemical properties of the nanoparticles. These nanoparticles are composed of silver atoms and silver alkylcarboxylates having even numbers, m, of carbon atoms from 8 to 18. As a measure of the structure of the nanoparticles, the ratio of the number of silver atoms (nAg) to that of alkylcarboxylates (ns) per nanoparticle was evaluated by means of titration through chemical oxidation, voltammetric currents, and thermal gravimetric analysis. It increased with an increase in m and ranged from 1.3 to 9.8. Properties of the nanoparticle have been exhibited in absorbance of the UV-vis spectra at the point of the proportionality to n(Ag), voltammetric currents of which values were close to the theoretical values at the diffusion of particle itself, and the m-independent kinetic energy of the thermal decomposition and the overpotential of the reduction. They are not observed for the composed species, that is, silver atoms and silver alkylcarboxylate molecules.
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Affiliation(s)
- Nianjun Yang
- Department of Applied Physics, University of Fukui, 3-9-1 Bunkyo, Fukui-shi, 910-8507 Japan
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Chaki NK, Vijayamohanan KP. Temperature-Induced Phase Transitions of the Ordered Superlattice Assembly of Au Nanoclusters. J Phys Chem B 2005; 109:2552-8. [PMID: 16851256 DOI: 10.1021/jp045709x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Superlattices of monolayer protected metallic and semiconducting nanoclusters have attracted significant attention due to their promising applications in nanotechnology. In this paper, we investigate the effect of temperature on the ordered superlattice structure of relatively larger sized Au nanoclusters passivated with dodecanethiol [ca. Au1415(RS)328] with the help of in situ temperature controlled X-ray diffraction (XRD) and infrared spectroscopy (IR) in conjunction with thermogravimetric (TG) and differential scanning calorimetric (DSC) analysis. In brief, monolayer protected Au nanoclusters (AuMPC) were prepared by a modified Brust synthesis technique, where dodecanethiol itself acts as both phase transfer and simultaneous capping agent during the reduction process, generating an average particle size of 3.72 +/- 0.4 nm after repeated solvent extraction and careful fractionation experiments. These particles are characterized with the help of UV-vis, transmission electron microscopic (TEM), IR, and NMR techniques, where effective capping as well as the superlattice formation on the TEM grid is evident from the combined analysis of these results. In situ low-angle XRD analysis shows that the particles undergo an irreversible phase transition in the temperature range of 100-115 degrees C, which is also reflected in the data from in situ IR analysis. However, the DSC analysis does not account for this phase transition, although the reversible phase transition due to the alkyl chain dynamics is in good agreement with the previously reported results. These results indicate the formation of temperature-induced, diffusion-limited phase transition involving nonequilibrium fractal structures, which is in good agreement with the previous available theoretical studies. The determination of the temperature window for the stability of these ordered assemblies would be used to understand the effect of thermal stress for device applications.
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Affiliation(s)
- Nirmalya Kumar Chaki
- Physical and Materials Chemistry Division, National Chemical Laboratory, Pune 411 008, India
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Abstract
Recent literature describing nanocomposites of metal nanoparticles and conjugated polymers and oligomers are reviewed. Preparation of these nanocomposites by chemical and electrochemical methods are described, and the electronic and optical properties of these materials are discussed. Some initial applications that have been investigated for such nanocomposites are covered.
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Affiliation(s)
- Bryan C Sih
- Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
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Chaki NK, Singh P, Dharmadhikari CV, Vijayamohanan KP. Single-electron charging features of larger, dodecanethiol-protected gold nanoclusters: electrochemical and scanning tunneling microscopy studies. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:10208-10217. [PMID: 15518515 DOI: 10.1021/la048489n] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In this report, we demonstrate the single-electron charging features of larger-sized (ca. 3.72 nm) Au nanoclusters protected with dodecanethiol [approximate composition, Au1415(RS)328] using combined electrochemical and scanning tunneling microscopic (STM) studies. In particular, these nanoclusters show a highly populated single-electron charging peak in voltammetric experiments, where the calculated capacitance is in good agreement with the experimentally obtained value of 1.6 aF. In comparison to the voltammetric studies, STM measurements over a single Au particle on the highly oriented pyrolytic graphite surface reveal nonlinear current-voltage (I-V) characteristics with a large central gap, signifying single-electron-transfer features. The I-V results demonstrate a clear Coulomb blockade effect with a central gap of around 0.2 eV, which is in good agreement with the orthodox theory for the double barrier tunnel junction system. The standard heterogeneous electron-transfer rate constant estimated from impedance measurements is found to be of 7.97 x 10(-6) cm.s(-1), suggesting that the process is very sluggish. Furthermore, diffusion coefficient (Dc) values calculated from chronoamperometry and impedance measurements are in good agreement with theoretically calculated values using the modified Stokes-Einstein equation. The electron-transfer rate constant estimated from cyclic voltammograms of adsorbed monolayer protected Au nanoclusters is found to be about 2 s(-1), which is slower than that reported for its smaller analogues.
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Affiliation(s)
- Nirmalya Kumar Chaki
- Physical and Materials Chemistry Division, National Chemical Laboratory, Pune 411008, India
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Quantized double layer charging of dodecanethiol protected larger Au nanoclusters: combined investigations using differential pulse voltammetry, cyclic voltammetry and impedance technique. Electrochem commun 2004. [DOI: 10.1016/j.elecom.2004.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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