101
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Holmes MA, Townsend TK, Osterloh FE. Quantum confinement controlled photocatalytic water splitting by suspended CdSe nanocrystals. Chem Commun (Camb) 2011; 48:371-3. [PMID: 22083249 DOI: 10.1039/c1cc16082f] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The photocatalytic hydrogen production of CdSe nanocrystals (1.75-4.81 nm) in the presence of aqueous sodium sulphite depends exponentially on the bandgap of the particles, confirming that the material's activity is controlled by the degree of quantum confinement.
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Affiliation(s)
- Michael A Holmes
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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102
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Santos FS, Costa TMH, Stefani V, Gonçalves PFB, Descalzo RR, Benvenutti EV, Rodembusch FS. Synthesis, Characterization, and Spectroscopic Investigation of Benzoxazole Conjugated Schiff Bases. J Phys Chem A 2011; 115:13390-8. [DOI: 10.1021/jp206905f] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Fabiano S. Santos
- Laboratório de Sólidos e Superfícies, ‡Laboratório de Novos Materiais Orgânicos, and §Grupo de Química Teórica e Computacional, Universidade Federal do Rio Grande do Sul - Instituto de Química, Avenida Bento Gonçalves, 9500, CP 15003, CEP 91501-970 Porto Alegre-RS, Brazil
| | - Tania M. H. Costa
- Laboratório de Sólidos e Superfícies, ‡Laboratório de Novos Materiais Orgânicos, and §Grupo de Química Teórica e Computacional, Universidade Federal do Rio Grande do Sul - Instituto de Química, Avenida Bento Gonçalves, 9500, CP 15003, CEP 91501-970 Porto Alegre-RS, Brazil
| | - Valter Stefani
- Laboratório de Sólidos e Superfícies, ‡Laboratório de Novos Materiais Orgânicos, and §Grupo de Química Teórica e Computacional, Universidade Federal do Rio Grande do Sul - Instituto de Química, Avenida Bento Gonçalves, 9500, CP 15003, CEP 91501-970 Porto Alegre-RS, Brazil
| | - Paulo F. B. Gonçalves
- Laboratório de Sólidos e Superfícies, ‡Laboratório de Novos Materiais Orgânicos, and §Grupo de Química Teórica e Computacional, Universidade Federal do Rio Grande do Sul - Instituto de Química, Avenida Bento Gonçalves, 9500, CP 15003, CEP 91501-970 Porto Alegre-RS, Brazil
| | - Rodrigo R. Descalzo
- Laboratório de Sólidos e Superfícies, ‡Laboratório de Novos Materiais Orgânicos, and §Grupo de Química Teórica e Computacional, Universidade Federal do Rio Grande do Sul - Instituto de Química, Avenida Bento Gonçalves, 9500, CP 15003, CEP 91501-970 Porto Alegre-RS, Brazil
| | - Edilson V. Benvenutti
- Laboratório de Sólidos e Superfícies, ‡Laboratório de Novos Materiais Orgânicos, and §Grupo de Química Teórica e Computacional, Universidade Federal do Rio Grande do Sul - Instituto de Química, Avenida Bento Gonçalves, 9500, CP 15003, CEP 91501-970 Porto Alegre-RS, Brazil
| | - Fabiano S. Rodembusch
- Laboratório de Sólidos e Superfícies, ‡Laboratório de Novos Materiais Orgânicos, and §Grupo de Química Teórica e Computacional, Universidade Federal do Rio Grande do Sul - Instituto de Química, Avenida Bento Gonçalves, 9500, CP 15003, CEP 91501-970 Porto Alegre-RS, Brazil
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103
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Chazalvel JN, Ozanam F. Mechanism of Electron Injection During the Anodic Oxidation of Silicon. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-283-359] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTn-Si photoanodes have been found to exhibit photocurrent multiplication during the first seconds of exposure to a fluoride-free, acidic electrolyte. This shows that, in contrast with earlier hypotheses, photocurrent doubling is not directly related to the presence of fluoride in the electrolyte, but rather must arise from an electron injection mechanism associated with the Si-H bonds initially present at the Si surface. It also suggests that the electroluminescence which has been observed during the anodic oxidation of porous silicon most probably stems from the same electron-injection mechanism.
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104
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Barnes PRF, Anderson AY, Durrant JR, O'Regan BC. Simulation and measurement of complete dye sensitised solar cells: including the influence of trapping, electrolyte, oxidised dyes and light intensity on steady state and transient device behaviour. Phys Chem Chem Phys 2011; 13:5798-816. [PMID: 21327204 DOI: 10.1039/c0cp01554g] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A numerical model of the dye sensitised solar cell (DSSC) is used to assess the importance of different loss pathways under various operational conditions. Based on our current understanding, the simulation describes the processes of injection, regeneration, recombination and transport of electrons, oxidised dye molecules and electrolyte within complete devices to give both time dependent and independent descriptions of performance. The results indicate that the flux of electrons lost from the nanocrystalline TiO(2) film is typically at least twice as large under conditions equivalent to 1 sun relative to dark conditions at matched TiO(2) charge concentration. This is in agreement with experimental observations (Barnes et al. Phys. Chem. Chem. Phys. [DOI: 10.1039/c0cp01855d]). The simulated difference in recombination flux is shown to be due to variation in the concentration profile of electron accepting species in the TiO(2) pores between light and dark conditions and to recombination to oxidised dyes in the light. The model is able to easily incorporate non-ideal behaviour of a cell such as the variation of open circuit potential with light intensity and non-first order recombination of conduction band electrons. The time dependent simulations, described by the multiple trapping model of electron transport and recombination, show good agreement with both small and large transient photocurrent and photovoltage measurements at open circuit, including photovoltage rise measurements. The simulation of photovoltage rise also suggests the possibility of assessing the interfacial resistance between the TiO(2) and substrate. When cells with a short diffusion length relative to film thickness were modelled, the simulated small perturbation photocurrent transients at short circuit (but not open circuit) yielded significantly higher effective diffusion coefficients than expected from the mean concentration of electrons and the electrolyte in the cell. This implies that transient measurements can overestimate the electron diffusion length in cells which have a low collection efficiency. The model should provide a useful general framework for exploring new cell descriptions, architectures and other factors influencing device performance.
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105
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Oskam G, Long JG, Nikolova M, Searson PC. Electrochemical Deposition of Metals on Semiconductors. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-451-257] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTThe general concepts governing the electrochemical deposition of metal films on semiconductors are discussed, and recent results on the fabrication of Schottky junctions consisting of silicon electrodeposited with platinum, copper and gold are presented. In order to obtain good adherent metal films, the density of nuclei should be high and the films should be grown at low current densities where the charge transfer process is rate limiting. This situation can be realized using potential controlled electrochemical deposition. For metal deposition on silicon, the surface should be pretreated in HF to dissolve the oxide layer. Furthermore, the surface should be stable during deposition which can be achieved by tailoring the deposition solutions and by using electrochemical deposition at negative potentials. It is shown that by using this approach, n-type silicon / Pt, Au, and Cu Schottky junctions can be fabricated of a quality comparable to that of junctions prepared by sputter and vapor deposition techniques.
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106
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Visible light photocatalysis by metal halide complexes containing titania as a semiconductor ligand. ADVANCES IN INORGANIC CHEMISTRY 2011. [DOI: 10.1016/b978-0-12-385904-4.00002-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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107
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He X, Cai Y, Zhang H, Liang C. Photocatalytic degradation of organic pollutants with Ag decorated free-standing TiO2nanotube arrays and interface electrochemical response. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c0jm02404j] [Citation(s) in RCA: 159] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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108
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La Mantia F, Habazaki H, Santamaria M, Di Quarto F. A critical assessment of the Mott-Schottky analysis for the characterisation of passive film-electrolyte junctions. RUSS J ELECTROCHEM+ 2010. [DOI: 10.1134/s102319351011011x] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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109
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Ehrensberger MT, Gilbert JL. The effect of scanning electrochemical potential on the short-term impedance of commercially pure titanium in simulated biological conditions. J Biomed Mater Res A 2010; 94:781-9. [PMID: 20336755 DOI: 10.1002/jbm.a.32736] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The electrochemical history (voltage-time variations) of titanium oxide-solution interfaces can vary widely in vivo, particularly where oxide abrasion is present, and it is important to assess the effects of voltage on the impedance behavior of the interface. Potential step impedance analysis (PSIA) utilizes a time and frequency domain methodology to assess the electrochemical impedance of electrified interfaces over a range of voltages. The PSIA method was used to study the combined effects of scanning electrical potential and the presence of solution-born organic species (protein, amino acids, etc.) on the electrochemical properties of cpTi. The specific solutions used in these scanning PSIA experiments were phosphate buffered saline and cell culture medium supplemented with 10% fetal bovine serum. The results show that electrochemical impedance properties of cpTi are voltage-time history dependent and strongly influenced by electrical potential within the -1000 mV to +1000 mV range studied. Moreover, the presence of biologically relevant molecules in the electrolyte solution alters the impedance properties only at cathodic potentials. Specifically, at cathodic potentials, these organic species have been shown to suppress the cathodic current density, shift the zero current potential in the cathodic direction, and increase the interfacial capacitance, polarization resistance, and the distribution of surface relaxation times. At anodic potentials, the presence of the organic species does not alter any of the electrochemical properties examined. Overall, these results show the importance of understanding of the variation in electrochemical potentials achievable in vivo and the effects voltage history has on interfacial electrochemical behavior.
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Affiliation(s)
- Mark T Ehrensberger
- Department of Orthopedic Surgery, State University of New York at Buffalo, Buffalo, New York 14214, USA
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110
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Lockett V, Horne M, Sedev R, Rodopoulos T, Ralston J. Differential capacitance of the double layer at the electrode/ionic liquids interface. Phys Chem Chem Phys 2010; 12:12499-512. [PMID: 20721389 DOI: 10.1039/c0cp00170h] [Citation(s) in RCA: 180] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The differential capacitance of the electrical double layer at glassy carbon, platinum and gold electrodes immersed in various ionic liquids was measured using impedance spectroscopy. We discuss the influence of temperature, the composition of the ionic liquids and the electrode material on the differential capacitance/potential curves. For different systems these curves have various overall shapes, but all include several extremes and a common minimum near the open circuit potential. We attribute this minimum to the potential of zero charge (PZC). Significantly, the differential capacitance generally decreases if the applied potential is large and moving away from the PZC. This is attributed to lattice saturation [A. A. Kornyshev, J. Phys. Chem. B, 2007, 111, 5545] effects which result in a thicker double layer. The differential capacitance of the double layer grows and specific adsorption diminishes with increasing temperature. Specific adsorption of both cations and anions influences the shapes of curves close to the PZC. The general shape of differential capacitance/potential does not depend strongly on the identity of the electrode material.
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Affiliation(s)
- Vera Lockett
- Ian Wark Research Institute, University of South Australia, Mawson Lakes, SA 5095, Australia.
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111
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112
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Radovic L. Surface Chemical and Electrochemical Properties of Carbons. ADVANCED MATERIALS AND TECHNOLOGIES 2009. [DOI: 10.1201/9781420055405-c5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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113
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Al-Hilli S, Willander M. The pH Response and Sensing Mechanism of n-Type ZnO/Electrolyte Interfaces. SENSORS (BASEL, SWITZERLAND) 2009; 9:7445-80. [PMID: 22423211 PMCID: PMC3290457 DOI: 10.3390/s90907445] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 09/09/2009] [Indexed: 11/29/2022]
Abstract
Ever since the discovery of the pH-sensing properties of ZnO crystals, researchers have been exploring their potential in electrochemical applications. The recent expansion and availability of chemical modification methods has made it possible to generate a new class of electrochemically active ZnO nanorods. This reduction in size of ZnO (to a nanocrystalline form) using new growth techniques is essentially an example of the nanotechnology fabrication principle. The availability of these ZnO nanorods opens up an entire new and exciting research direction in the field of electrochemical sensing. This review covers the latest advances and mechanism of pH-sensing using ZnO nanorods, with an emphasis on the nano-interface mechanism. We discuss methods for calculating the effect of surface states on pH-sensing at a ZnO/electrolyte interface. All of these current research topics aim to explain the mechanism of pH-sensing using a ZnO bulk- or nano-scale single crystal. An important goal of these investigations is the translation of these nanotechnology-modified nanorods into potential novel applications.
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Affiliation(s)
- Safaa Al-Hilli
- Department of Science and Technology, Campus Norrköping, Linköping University, SE-60174 Norrköping, Sweden; E-Mail:
| | - Magnus Willander
- Department of Science and Technology, Campus Norrköping, Linköping University, SE-60174 Norrköping, Sweden; E-Mail:
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114
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Hahn R, Schmidt-Stein F, Salonen J, Thiemann S, Song Y, Kunze J, Lehto VP, Schmuki P. Semimetallic TiO2Nanotubes. Angew Chem Int Ed Engl 2009; 48:7236-9. [DOI: 10.1002/anie.200902207] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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115
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Hahn R, Schmidt-Stein F, Salonen J, Thiemann S, Song Y, Kunze J, Lehto VP, Schmuki P. Semimetallic TiO2Nanotubes. Angew Chem Int Ed Engl 2009. [DOI: 10.1002/ange.200902207] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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116
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117
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Gettens RTT, Gilbert JL. The electrochemical impedance of polarized 316L stainless steel: structure-property-adsorption correlation. J Biomed Mater Res A 2009; 90:121-32. [PMID: 18491379 DOI: 10.1002/jbm.a.32051] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Electrochemical (EC) impedance and polarization data were synergistically coupled with AFM micrographs providing insight on the polarized alloy-electrolyte interface. Several regions of oxide topography/ impedance characteristic were apparent on a 316L SS surface. A relatively rough surface with apparent EC reaction products was observed below -500 mV. Smooth surfaces were seen from -500 mV to 200 mV. A transition region which displayed the aggregation of particles on the surface was seen from 200 mV to 600 mV. Above 600 mV these particles disappeared revealing a smooth topography. These topographical observations matched closely with the impedance behavior of the system, particularly the capacitance (C), polarization resistance (R(p)) and current density. The presence of pre-adsorbed Fb had a significant impact on C below approximately -500 mV (increased capacitance). The deviation from ideality of the current response as determined by a KWW empirical dielectric decay function showed significant differences between PBS-immersed and pre-adsorbed Fb cases. Earlier, changes in Fb area coverage, height, and eccentricity were observed between voltages lower and higher than 0 mV. The presence of the flat-band potential around -150 mV as well as high cathodic charge-transfer reactions taking place below -100 mV relate to these observations.
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Affiliation(s)
- Robert T T Gettens
- Department of Biomedical Engineering, Western New England College, Springfield, Massachusetts 01106, USA
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118
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Photoelectrocatalytic degradation of the insecticide imidacloprid using TiO2/Ti electrodes. J Photochem Photobiol A Chem 2009. [DOI: 10.1016/j.jphotochem.2009.03.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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119
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120
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121
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Pilbáth Z, Sziráki L. The electrochemical reduction of oxygen on zinc corrosion films in alkaline solutions. Electrochim Acta 2008. [DOI: 10.1016/j.electacta.2007.11.056] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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122
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Ocakoglu K, Yildirim Y, Yurt Lambrecht F, Ocal J, Icli S. Biological investigation of 131I-labeled new water soluble Ru(II) polypyridyl complex. Appl Radiat Isot 2008; 66:115-21. [PMID: 17913501 DOI: 10.1016/j.apradiso.2007.07.033] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2006] [Revised: 07/17/2007] [Accepted: 07/20/2007] [Indexed: 10/22/2022]
Abstract
New [Ru(L1)(dcbpy)(NCS)2] complex was synthesized in a one-pot reaction starting from [RuCl2(p-cymene)]2, where the ligands (dcbpy=4,4'-dicarboxy-2,2'-bipyridine, L1=dipyrido[3,2-a:2',3'-c]phenazine-11-ylcarbonyl)-sodium) are introduced sequentially. The resulting complex was characterized by IR, NMR, and elemental analysis. The complex was labeled with I-131. Biodistribution study of the complex was carried out using 131I-labeled [Ru(L1)(dcbpy)(NCS)2] complex. The biodistribution study performed with albino Wistar male rats has shown that the complex has high uptake in the lung, small intestine, fat, and spleen.
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Affiliation(s)
- Kasim Ocakoglu
- Solar Energy Institute, Department of Chemistry, Faculty of Science, Ege University, 35100 Bornova, Izmir, Turkey.
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123
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Bisquert J, Fabregat-Santiago F, Mora-Seró I, Garcia-Belmonte G, Barea EM, Palomares E. A review of recent results on electrochemical determination of the density of electronic states of nanostructured metal-oxide semiconductors and organic hole conductors. Inorganica Chim Acta 2008. [DOI: 10.1016/j.ica.2007.05.032] [Citation(s) in RCA: 224] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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124
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Schliephake H, Scharnweber D. Chemical and biological functionalization of titanium for dental implants. ACTA ACUST UNITED AC 2008. [DOI: 10.1039/b715355b] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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125
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Chapter 16 Growth and Etching of Semiconductors. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/s1573-4331(08)00016-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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126
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127
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Beranek R, Neumann B, Sakthivel S, Janczarek M, Dittrich T, Tributsch H, Kisch H. Exploring the electronic structure of nitrogen-modified TiO2 photocatalysts through photocurrent and surface photovoltage studies. Chem Phys 2007. [DOI: 10.1016/j.chemphys.2007.05.022] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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128
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Tse KY, Nichols BM, Yang W, Butler JE, Russell JN, Hamers RJ. Electrical properties of diamond surfaces functionalized with molecular monolayers. J Phys Chem B 2007; 109:8523-32. [PMID: 16852003 DOI: 10.1021/jp046433w] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recent studies have shown that semiconductor surfaces such as silicon and diamond can be functionalized with organic monolayers, and that these monolayer films can be used to tether biomolecules such as DNA to the surfaces. Electrical measurements of these interfaces show a change in response to DNA hybridization and other biological binding processes, but the fundamental nature of the electrical signal transduction has remained unclear. We have explored the electrical impedance of polycrystalline and single-crystal diamond surfaces modified with an organic monolayer produced by photochemical reaction of diamond with 1-dodecene. Our results show that, by measuring the impedance as a function of frequency and potential, it is possible to dissect the complex interfacial structure into frequency ranges where the total impedance is controlled by the molecular monolayer, by the diamond space-charge region, and by the electrolyte. The results have implications for understanding the ability to use molecularly modified semiconductor surfaces for applications such as chemical and biological sensing.
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Affiliation(s)
- Kiu-Yuen Tse
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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129
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Zawisza I, Bin X, Lipkowski J. Potential-driven structural changes in Langmuir-Blodgett DMPC bilayers determined by in situ spectroelectrochemical PM IRRAS. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:5180-94. [PMID: 17373832 DOI: 10.1021/la063190l] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Combined Langmuir-Blodgett vertical withdrawing and Langmuir-Schaefer horizontal touch (LB-LS) methods were employed to transfer DMPC bilayers onto a Au(111) electrode surface. Charge density measurements and photon polarization modulation infrared reflection absorption spectroscopy were employed to investigate electric field induced changes in the structure of the bilayer. The results show that the physical state and the molecular arrangement found in the monolayer at the air-water interface is to a large extent preserved in the bilayer formed by the LB-LS method. This approach provides an opportunity to produce supported bilayers with a well-designed architecture. The properties of the bilayer formed by the LB-LS method were compared to the properties of the bilayer produced by spontaneous fusion of unilamellar vesicles investigated in an earlier study (Bin, X.; Zawisza, I.; Lipkowski, J. Langmuir 2005, 21, 330-347). The tilt angles of the acyl chains are much smaller in the bilayer formed by the LB-LS method and are closer to the angles observed for vesicles and stacked hydrated bilayers. The tilt angles of the phosphate and choline groups are also smaller and are characteristic of an orientation in which the area per DMPC molecule is small. The electric field induced changes of these angles are also less pronounced in the bilayer formed by the LB-LS method. We have shown that these differences are a result of the higher packing density of the phospholipid molecules in the bilayer formed by the LB-LS method.
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Affiliation(s)
- Izabella Zawisza
- Department of Chemistry and Biochemistry, University of Guelph, Guelph, N1G2W1, Ontario, Canada
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130
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Bignozzi CA, Schoonover JR, Scandola F. A Supramolecular Approach to Light Harvesting and Sensitization of Wide-Bandgap Semiconductors: Antenna Effects and Charge Separation. PROGRESS IN INORGANIC CHEMISTRY 2007. [DOI: 10.1002/9780470166451.ch1] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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131
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Tan MX, Laibinis PE, Nguyen ST, Kesselman JM, Stanton CE, Lewis NS. Principles and Applications of Semiconductor Photoelectrochemistry. PROGRESS IN INORGANIC CHEMISTRY 2007. [DOI: 10.1002/9780470166420.ch2] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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132
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Gerfin T, Grätzel M, Walder L. Molecular and Supramolecular Surface Modification of Nanocrystalline TiO2Films: Charge-Separating and Charge-Injecting Devices. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/9780470166451.ch7] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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133
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134
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Asanuma H, Bishop EM, Yu HZ. Electrochemical impedance and solid-state electrical characterization of silicon (111) modified with ω-functionalized alkyl monolayers. Electrochim Acta 2007. [DOI: 10.1016/j.electacta.2006.08.060] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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135
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Quantum chemical modelling of oxygen reduction on cobalt hydroxide and oxyhydroxide. J Electroanal Chem (Lausanne) 2007. [DOI: 10.1016/j.jelechem.2006.05.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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136
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Metikos-Huković M, Pilić Z, Babić R, Omanović D. Influence of alloying elements on the corrosion stability of CoCrMo implant alloy in Hank's solution. Acta Biomater 2006; 2:693-700. [PMID: 16884967 DOI: 10.1016/j.actbio.2006.06.002] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Revised: 05/26/2006] [Accepted: 06/06/2006] [Indexed: 11/22/2022]
Abstract
The behavior of a CoCrMo alloy and its components was studied in simulated physiological solution (Hank's solution) using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The passivation of all samples occurred spontaneously at the open circuit potential. The composition of the oxide films as a function of the solution components and the applied potential is discussed. The electrochemical properties of the spontaneously passivated electrodes at the open circuit potential were studied by EIS. The polarization resistance (R(p)) and the electrode capacitance (C(dl)) were determined. The higher R(p) of the alloy than of the chromium pointed to the stabilizing effect of the other alloy components. The concentration of the metallic ions in a simulated physiological solution, measured by inductively coupled plasma-mass spectrometry, was in accordance with the values of both the R(p) determined from EIS data and current densities measured with CV.
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Affiliation(s)
- Mirjana Metikos-Huković
- Department of Electrochemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Savska 16, P.O. Box 177, 10000 Zagreb, Croatia.
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137
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Palmas S, Polcaro AM, Vacca A, Mascia M, Ferrara F. Characterization of boron doped diamond during oxidation processes: Relationship between electronic structure and electrochemical activity. J APPL ELECTROCHEM 2006. [DOI: 10.1007/s10800-006-9210-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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138
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Investigation of a semiconductor bioelectrode with Ohmic behavior in vivo: Impedance spectroscopy of p-type semiconductor electrodes in perfused living heart. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2005.11.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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139
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140
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Sakai N, Ebina Y, Takada K, Sasaki T. Photocurrent Generation from Semiconducting Manganese Oxide Nanosheets in Response to Visible Light. J Phys Chem B 2005; 109:9651-5. [PMID: 16852162 DOI: 10.1021/jp0500485] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Unilamellar nanosheet crystallites of manganese oxide generated the anodic photocurrent under visible light irradiation (lambda < 500 nm), while the nanosheets themselves were stable as revealed by in-plane XRD and UV-visible absorption spectra. The band gap energy was estimated to be 2.23 eV on the basis of the photocurrent action spectrum. The molecular thickness of approximately 0.5 nm may facilitate the charge separation of excited electrons and holes, which is generally very difficult for strongly localized d-d transitions. The monolayer film of MnO2 nanosheets exhibited the incident photon-to-electron conversion efficiency of 0.16% in response to the monochromatic light irradiation (lambda = 400 nm), which is comparable to those for sensitization of monolayer dyes adsorbed on a flat single-crystal surface. The efficiency declined with increasing the layer number of MnO2 nanosheets, although the optical absorption was enhanced. The recombination of the excited electron-hole pairs may become dominant when the carriers need to migrate a longer distance than 1 layer through multilayered nanosheets.
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Affiliation(s)
- Nobuyuki Sakai
- Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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141
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A preliminary study on chemical micro-machining of complex three-dimensional patterns on silicon substrates. J Solid State Electrochem 2005. [DOI: 10.1007/s10008-004-0636-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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142
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Electrochemical characterisation and oxygen evolution at a heavily boron doped diamond electrode. Electrochim Acta 2005. [DOI: 10.1016/j.electacta.2004.08.050] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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143
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Noel M, Suryanarayanan N. Electrochemistry of metals and semiconductors in fluoride media. J APPL ELECTROCHEM 2005. [DOI: 10.1007/s10800-004-2400-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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144
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Hubin A, Simons W, Pauwels L, Vereecken J. Reduction of silver complexes: towards an ever more elaborated insight in the influence of the type of ligand on the reaction rate. J Electroanal Chem (Lausanne) 2004. [DOI: 10.1016/j.jelechem.2004.04.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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145
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146
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Chemla M, Durand-Vidal S, Zanna S, Petitdidier S, Levy D. Silicon surface wet cleaning and chemical oxide growth by a novel treatment in aqueous chlorine solutions. Electrochim Acta 2004. [DOI: 10.1016/j.electacta.2004.03.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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147
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Nakamura R, Nakato Y. Primary intermediates of oxygen photoevolution reaction on TiO2 (Rutile) particles, revealed by in situ FTIR absorption and photoluminescence measurements. J Am Chem Soc 2004; 126:1290-8. [PMID: 14746503 DOI: 10.1021/ja0388764] [Citation(s) in RCA: 393] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Primary intermediates of oxygen photoevolution (water photooxidation) reaction at the TiO2 (rutile)/aqueous solution interface were investigated by in situ multiple internal reflection infrared (MIRIR) absorption and photoluminescence (PL) measurements. UV irradiation of TiO2 in the presence of 10 mM Fe3+ in the solution caused the appearance of a new peak at 838 cm(-1) and a shoulder at 812 cm(-1). Detailed investigations of the effects of solution pH, the presence of methanol as a hole scavenger, and isotope exchange in water (H2(16)O-->H2(18)O) on the spectra have shown that the 838- and 812-cm(-1) bands can be assigned to the O-O stretching mode of surface TiOOH and TiOOTi, respectively, produced as primary intermediates of the oxygen photoevolution reaction. The results give strong support to our previously proposed mechanism that the oxygen photoevolution is initiated by a nucleophilic attack of a H2O molecule on a photogenerated hole at a surface lattice O site, not by oxidation of surface OH group by the hole. The conclusion is supported by PL measurements. A plausible reaction scheme is proposed for the oxygen photoevolution on TiO2 (rutile) in aqueous solutions of pH less than about 12.
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Affiliation(s)
- Ryuhei Nakamura
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
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148
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Sakai N, Ebina Y, Takada K, Sasaki T. Electronic Band Structure of Titania Semiconductor Nanosheets Revealed by Electrochemical and Photoelectrochemical Studies. J Am Chem Soc 2004; 126:5851-8. [PMID: 15125677 DOI: 10.1021/ja0394582] [Citation(s) in RCA: 232] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electrochemical and photoelectrochemical studies were conducted on self-assembled multilayer films of titania nanosheets on a conductive ITO substrate. Cyclic voltammogram (CV) curves indicated that the titania nanosheet electrode underwent insertion/extraction of Li(+) ions into/from the nanosheet galleries, associated with reduction/oxidation of Ti(4+)/Ti(3+). These processes accompanied reversible changes in UV-vis absorption of the titania nanosheet electrodes. Applying a negative bias of -1.3 V (vs Ag/Ag(+)) and lower brought about absorption reduction where the wavelength is shorter than 323 nm, and vice versa, indicating a flat-band potential of (approximately) -1.3 V and a band gap energy of 3.84 eV. Photocurrents were generated from the titania nanosheet electrodes under a positive bias. The onset potential for photocurrent generation from the titania nanosheet electrodes was around -1.27 V, and the band gap energy estimated from the photocurrent action spectra was 3.82 eV, in excellent agreement with the values obtained from the spectroelectrochemical data. The lack of difference in the band gap energies for titania nanosheet electrodes with different numbers of layers suggests that a nanosheet is electronically isolated in multilayer assemblies without affecting the electronic state of neighboring nanosheets. Similar measurements on the anatase-type TiO(2) electrode revealed that the lower edge of the conduction band for the titania nanosheet is approximately 0.1 V higher than that for anatase, while the upper edge of the valence band is 0.5 V lower.
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Affiliation(s)
- Nobuyuki Sakai
- Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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149
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CHEMLA M, LEVY D, PETITDIDIER S, ROUELLE F, ZANNA S. Silicon Chemical Oxide Growth by a Novel Wet Treatment in Aqueous Chlorine Solutions. ELECTROCHEMISTRY 2004. [DOI: 10.5796/electrochemistry.72.238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Marius CHEMLA
- Laboratoire d'Electrochimie, LI2C, Université P. & M. Curie
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150
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Chemla M, Homma T, Bertagna V, Erre R, Kubo N, Osaka T. Survey of the metal nucleation processes on silicon surfaces in fluoride solutions: from dilute HF to concentrated NH4F solutions. J Electroanal Chem (Lausanne) 2003. [DOI: 10.1016/s0022-0728(02)01280-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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