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Wang L, Chen Y, Zhang C, Zhong Z, Amirav L. Porous In 2O 3 Hollow Tube Infused with g-C 3N 4 for CO 2 Photocatalytic Reduction. ACS Appl Mater Interfaces 2024; 16:4581-4591. [PMID: 38232351 DOI: 10.1021/acsami.3c14826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Converting CO2 into energy-rich fuels by using solar energy is a sustainable solution that promotes a carbon-neutral economy and mitigates our reliance on fossil fuels. However, affordable and efficient CO2 conversion remains an ongoing challenge. Here, we introduce polymeric g-C3N4 into the pores of a hollow In2O3 microtube. This architecture results in a compact and staggered arrangement between g-C3N4 and In2O3 components with an increased contact interface for improved charge separation. The hollow interior further contributes to strengthening light absorption. The resulting g-C3N4-In2O3 hollow tubes exhibit superior activity (274 μmol·g-1·h-1) toward CO2 to CO conversion in comparison with those of pure In2O3 and g-C3N4 (5.5 and 93.6 μmol·g-1·h-1, respectively), underlining the role of integrating g-C3N4 and In2O3 in this advanced system. This work offers a strategy for the advanced design and preparation of hollow heterostructures for optimizing CO2 adsorption and conversion by integrating inorganic and organic semiconductors.
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Affiliation(s)
- Letian Wang
- Department of Chemical Engineering, Guangdong Technion-Israel Institute of Technology (GTIIT), Guangdong 515063, China
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
- Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology, Guangdong 515063, China
| | - Yuexing Chen
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Chenchen Zhang
- Department of Chemical Engineering, Guangdong Technion-Israel Institute of Technology (GTIIT), Guangdong 515063, China
- Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology, Guangdong 515063, China
| | - Ziyi Zhong
- Department of Chemical Engineering, Guangdong Technion-Israel Institute of Technology (GTIIT), Guangdong 515063, China
- Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology, Guangdong 515063, China
| | - Lilac Amirav
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
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Abstract
The significant role of metal particle geometry in dictating catalytic activity, selectivity, and stability is well established in heterocatalysis. However, this topic is rarely explored in semiconductor-metal hybrid photocatalytic systems, primarily due to the lack of synthetic control over this feature. Herein, we present a new synthetic route for the deposition of metallic Cu nanoparticles with spherical, elliptic, or cubic geometrical shapes, which are selectively grown on one side of the well-established CdSe@CdS nanorod photocatalytic system. An additional multipod morphology in which several nanorod branches are combined on a single Cu domain is presented as well. Cu is an earth-abundant low-cost catalyst known to promote a diverse gallery of organic transformations and is an excellent thermal and electrical conductor with interesting plasmonic properties. Its deposition on cadmium chalcogenide nanostructures is enabled here via mitigation of the reaction kinetics such that the cation exchange reaction is prevented. The structural diversity of these sophisticated nanoscale hybrid systems lays the foundations for shape-activity correlation studies and employment in various applications.
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Affiliation(s)
- Yuexing Chen
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology Haifa 32000 Israel
| | - Lilac Amirav
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology Haifa 32000 Israel
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3
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Micheel M, Dong K, Amirav L, Wächtler M. Lateral charge migration in 1D semiconductor-metal hybrid photocatalytic systems. J Chem Phys 2023; 158:2882241. [PMID: 37093989 DOI: 10.1063/5.0144785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 03/24/2023] [Indexed: 04/26/2023] Open
Abstract
Colloidal nanorods based on CdS or CdSe, functionalized with metal particles, have proven to be efficient catalysts for light-driven hydrogen evolution. Seeded CdSe@CdS nanorods have shown increasing performance with increasing rod length. This observation was rationalized by the increasing lifetime of the separated charges, as a large distance between holes localized in the CdSe seed and electrons localized at the metal tip decreases their recombination rate. However, the impact of nanorod length on the electron-to-tip localization efficiency or pathway remained an open question. Therefore, we investigated the photo-induced electron transfer to the metal in a series of Ni-tipped CdSe@CdS nanorods with varying length. We find that the transfer processes occurring from the region close to the semiconductor-metal interface, the rod region, and the CdSe seed region depend in different ways on the rods' length. The rate of the fastest process from excitonic states generated directly at the interface is independent of the rod length, but the relative amplitude decreases with increasing rod length, as the weight of the interface region is decreasing. The transfer of electrons to the metal tip from excitons generated in the CdS rod region depends strongly on the length of the nanorods, which indicates an electron transport-limited process, i.e., electron diffusion toward the interface region, followed by fast interface crossing. The transfer originating from the CdSe excitonic states again shows no significant length dependence in its time constant, as it is probably limited by the rate of overcoming the shallow confinement in the CdSe seed.
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Affiliation(s)
- Mathias Micheel
- Department Functional Interfaces, Leibniz-Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Kaituo Dong
- Schulich Faculty of Chemistry, The Russell Berrie Nanotechnology Institute, The Nancy and Stephen Grand Technion Energy Program, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Lilac Amirav
- Schulich Faculty of Chemistry, The Russell Berrie Nanotechnology Institute, The Nancy and Stephen Grand Technion Energy Program, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Maria Wächtler
- Department Functional Interfaces, Leibniz-Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany
- Chemistry Department and State Research Center Optimas, RPTU Kaiserslautern-Landau, Erwin-Schrödinger-Straße 52, 67663 Kaiserslautern, Germany
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Abstract
The existence of a reduced Schottky barrier at the nanoscale junction between semiconductor and metal domains has yet to be acknowledged among the photocatalysis community, despite its critical role in dictating the quality and functionality of the hybrid photocatalytic system.
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Affiliation(s)
- Lilac Amirav
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Maria Wächtler
- Technische Universität Kaiserslautern, Fachbereich Chemie, Erwin-Schrödinger-Straße 21, 67663 Kaiserslautern, Germany
- Department Functional Interfaces, Leibniz Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany
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Rosner T, Pavlopoulos NG, Shoyhet H, Micheel M, Wächtler M, Adir N, Amirav L. The Other Dimension-Tuning Hole Extraction via Nanorod Width. Nanomaterials (Basel) 2022; 12:nano12193343. [PMID: 36234471 PMCID: PMC9565346 DOI: 10.3390/nano12193343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/14/2022] [Accepted: 09/21/2022] [Indexed: 05/10/2023]
Abstract
Solar-to-hydrogen generation is a promising approach to generate clean and renewable fuel. Nanohybrid structures such as CdSe@CdS-Pt nanorods were found favorable for this task (attaining 100% photon-to-hydrogen production efficiency); yet the rods cannot support overall water splitting. The key limitation seems to be the rate of hole extraction from the semiconductor, jeopardizing both activity and stability. It is suggested that hole extraction might be improved via tuning the rod's dimensions, specifically the width of the CdS shell around the CdSe seed in which the holes reside. In this contribution, we successfully attain atomic-scale control over the width of CdSe@CdS nanorods, which enables us to verify this hypothesis and explore the intricate influence of shell diameter over hole quenching and photocatalytic activity towards H2 production. A non-monotonic effect of the rod's diameter is revealed, and the underlying mechanism for this observation is discussed, alongside implications towards the future design of nanoscale photocatalysts.
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Affiliation(s)
- Tal Rosner
- Schulich Faculty of Chemistry, The Russell Berrie Nanotechnology Institute, The Nancy and Stephen Grand Technion Energy Program, Technion−Israel Institute of Technology, Haifa 32000, Israel
| | - Nicholas G. Pavlopoulos
- Schulich Faculty of Chemistry, The Russell Berrie Nanotechnology Institute, The Nancy and Stephen Grand Technion Energy Program, Technion−Israel Institute of Technology, Haifa 32000, Israel
| | - Hagit Shoyhet
- Schulich Faculty of Chemistry, The Russell Berrie Nanotechnology Institute, The Nancy and Stephen Grand Technion Energy Program, Technion−Israel Institute of Technology, Haifa 32000, Israel
| | - Mathias Micheel
- Department Functional Interfaces, Leibniz Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Maria Wächtler
- Department Functional Interfaces, Leibniz Institute of Photonic Technology Jena, Albert-Einstein-Straße 9, 07745 Jena, Germany
- Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Helmholtzweg 4, 07743 Jena, Germany
- Correspondence: (M.W.); (N.A.); (L.A.)
| | - Noam Adir
- Schulich Faculty of Chemistry, The Russell Berrie Nanotechnology Institute, The Nancy and Stephen Grand Technion Energy Program, Technion−Israel Institute of Technology, Haifa 32000, Israel
- Correspondence: (M.W.); (N.A.); (L.A.)
| | - Lilac Amirav
- Schulich Faculty of Chemistry, The Russell Berrie Nanotechnology Institute, The Nancy and Stephen Grand Technion Energy Program, Technion−Israel Institute of Technology, Haifa 32000, Israel
- Correspondence: (M.W.); (N.A.); (L.A.)
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Dong K, Le TA, Nakibli Y, Schleusener A, Wächtler M, Amirav L. Molecular Metallocorrole-Nanorod Photocatalytic System for Sustainable Hydrogen Production. ChemSusChem 2022; 15:e202201525. [PMID: 35789067 DOI: 10.1002/cssc.202201525] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/30/2022] [Indexed: 05/25/2023]
Abstract
Solar-driven photocatalytic generation of hydrogen from water is a potential source of clean and renewable fuel. Yet systems that are sufficiently stable and efficient for practical use have not been realized. Here, nanorod photocatalysts that have proven record activity for the water reduction half reaction were successfully combined with molecular metallocorroles suitable for catalyzing the accompanying oxidation reactions. Utilization of OH- /⋅OH redox species as charge transfer shuttle between freely mixed metallocorroles and rods resulted in quantum efficiency that peaked as high as 17 % for hydrogen production from water in the absence of sacrificial hole scavengers. While typically each sacrificial scavenger is able to extract but a single hole, here the molecular metallocorrole catalysts were found to successfully handle nearly 300,000 holes during their lifespan. The implications of the new system on the prospects of realizing practical overall water splitting and direct solar-to-fuel energy conversion were discussed.
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Affiliation(s)
- Kaituo Dong
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, 32000, Israel
- Current address of T.-A. Le: Faculty of science and engineering, Åbo Akademi University, Turku, 20500, Finland
| | - Trung-Anh Le
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, 32000, Israel
- Current address of T.-A. Le: Faculty of science and engineering, Åbo Akademi University, Turku, 20500, Finland
| | - Yifat Nakibli
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, 32000, Israel
- Current address of T.-A. Le: Faculty of science and engineering, Åbo Akademi University, Turku, 20500, Finland
| | - Alexander Schleusener
- Leibniz Institute of Photonic Technology, Albert-Einstein-Straße 9, 07745, Jena, Germany
- Current address of Dr. A. Schleusener: Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genova, Italy
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany
| | - Maria Wächtler
- Leibniz Institute of Photonic Technology, Albert-Einstein-Straße 9, 07745, Jena, Germany
- Current address of Dr. A. Schleusener: Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genova, Italy
- Institute of Physical Chemistry, Friedrich Schiller University Jena, Helmholtzweg 4, 07743, Jena, Germany
- Abbe Center of Photonics, Albert-Einstein-Straße 6, 07745, Jena, Germany
| | - Lilac Amirav
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, 32000, Israel
- Current address of T.-A. Le: Faculty of science and engineering, Åbo Akademi University, Turku, 20500, Finland
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Dong K, Le T, Nakibli Y, Schleusener A, Wächtler M, Amirav L. Molecular Metallocorrole-Nanorod Photocatalytic System for Sustainable Hydrogen Production. ChemSusChem 2022; 15:e202200804. [PMID: 35789067 PMCID: PMC9540064 DOI: 10.1002/cssc.202200804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/30/2022] [Indexed: 06/15/2023]
Abstract
Solar-driven photocatalytic generation of hydrogen from water is a potential source of clean and renewable fuel. Yet systems that are sufficiently stable and efficient for practical use have not been realized. Here, nanorod photocatalysts that have proven record activity for the water reduction half reaction were successfully combined with molecular metallocorroles suitable for catalyzing the accompanying oxidation reactions. Utilization of OH- /⋅OH redox species as charge transfer shuttle between freely mixed metallocorroles and rods resulted in quantum efficiency that peaked as high as 17 % for hydrogen production from water in the absence of sacrificial hole scavengers. While typically each sacrificial scavenger is able to extract but a single hole, here the molecular metallocorrole catalysts were found to successfully handle nearly 300,000 holes during their lifespan. The implications of the new system on the prospects of realizing practical overall water splitting and direct solar-to-fuel energy conversion were discussed.
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Affiliation(s)
- Kaituo Dong
- Schulich Faculty of ChemistryTechnion – Israel Institute of TechnologyHaifa32000Israel
- Current address of T.-A. Le: Faculty of science and engineeringÅbo Akademi UniversityTurku20500Finland
| | - Trung‐Anh Le
- Schulich Faculty of ChemistryTechnion – Israel Institute of TechnologyHaifa32000Israel
- Current address of T.-A. Le: Faculty of science and engineeringÅbo Akademi UniversityTurku20500Finland
| | - Yifat Nakibli
- Schulich Faculty of ChemistryTechnion – Israel Institute of TechnologyHaifa32000Israel
- Current address of T.-A. Le: Faculty of science and engineeringÅbo Akademi UniversityTurku20500Finland
| | - Alexander Schleusener
- Leibniz Institute of Photonic TechnologyAlbert-Einstein-Straße 907745JenaGermany
- Current address of Dr. A. Schleusener: Istituto Italiano di TecnologiaVia Morego 3016163GenovaItaly
- Institute of Physical ChemistryFriedrich Schiller University JenaHelmholtzweg 407743JenaGermany
| | - Maria Wächtler
- Leibniz Institute of Photonic TechnologyAlbert-Einstein-Straße 907745JenaGermany
- Current address of Dr. A. Schleusener: Istituto Italiano di TecnologiaVia Morego 3016163GenovaItaly
- Institute of Physical ChemistryFriedrich Schiller University JenaHelmholtzweg 407743JenaGermany
- Abbe Center of PhotonicsAlbert-Einstein-Straße 607745JenaGermany
| | - Lilac Amirav
- Schulich Faculty of ChemistryTechnion – Israel Institute of TechnologyHaifa32000Israel
- Current address of T.-A. Le: Faculty of science and engineeringÅbo Akademi UniversityTurku20500Finland
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8
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Wang L, Etim UJ, Zhang C, Amirav L, Zhong Z. CO2 Activation and Hydrogenation on Cu-ZnO/Al2O3 Nanorod Catalysts: An In Situ FTIR Study. Nanomaterials 2022; 12:nano12152527. [PMID: 35893495 PMCID: PMC9331868 DOI: 10.3390/nano12152527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 07/15/2022] [Accepted: 07/15/2022] [Indexed: 12/07/2022]
Abstract
CuZnO/Al2O3 is the industrial catalyst used for methanol synthesis from syngas (CO + H2) and is also promising for the hydrogenation of CO2 to methanol. In this work, we synthesized Al2O3 nanorods (n-Al2O3) and impregnated them with the CuZnO component. The catalysts were evaluated for the hydrogenation of CO2 to methanol in a fixed-bed reactor. The support and the catalysts were characterized, including via in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The study of the CO2 adsorption, activation, and hydrogenation using in situ DRIFT spectroscopy revealed the different roles of the catalyst components. CO2 mainly adsorbed on the n-Al2O3 support, forming carbonate species. Cu was found to facilitate H2 dissociation and further reacted with the adsorbed carbonates on the n-Al2O3 support, transforming them to formate or additional intermediates. Like the n-Al2O3 support, the ZnO component contributed to improving the CO2 adsorption, facilitating the formation of more carbonate species on the catalyst surface and enhancing the efficiency of the CO2 activation and hydrogenation into methanol. The synergistic interaction between Cu and ZnO was found to be essential to increase the space–time yield (STY) of methanol but not to improve the selectivity. The 3% CuZnO/n-Al2O3 displayed improved catalytic performance compared to 3% Cu/n-Al2O3, reaching a CO2 conversion rate of 19.8% and methanol STY rate of 1.31 mmolgcat−1h−1 at 300 °C. This study provides fundamental and new insights into the distinctive roles of the different components of commercial methanol synthesis catalysts.
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Affiliation(s)
- Letian Wang
- Department of Chemical Engineering, Guangdong Technion-Israel Institute of Technology (GTIIT), Shantou 515063, China; (L.W.); (U.J.E.); (C.Z.)
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology (IIT), Haifa 32000, Israel
| | - Ubong Jerome Etim
- Department of Chemical Engineering, Guangdong Technion-Israel Institute of Technology (GTIIT), Shantou 515063, China; (L.W.); (U.J.E.); (C.Z.)
| | - Chenchen Zhang
- Department of Chemical Engineering, Guangdong Technion-Israel Institute of Technology (GTIIT), Shantou 515063, China; (L.W.); (U.J.E.); (C.Z.)
| | - Lilac Amirav
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology (IIT), Haifa 32000, Israel
- Correspondence: (L.A.); (Z.Z.)
| | - Ziyi Zhong
- Department of Chemical Engineering, Guangdong Technion-Israel Institute of Technology (GTIIT), Shantou 515063, China; (L.W.); (U.J.E.); (C.Z.)
- Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion (MATEC), Guangdong Technion-Israel Institute of Technology (GTIIT), Shantou 515063, China
- Correspondence: (L.A.); (Z.Z.)
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Shaik F, Milan R, Amirav L. Gold@Carbon Nitride Yolk and Core-Shell Nanohybrids. ACS Appl Mater Interfaces 2022; 14:21340-21347. [PMID: 35467354 DOI: 10.1021/acsami.2c01906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Graphitic carbon nitride (g-C3N4) is a promising conjugated polymer with visible light responsiveness and numerous intriguing characteristics that make it highly beneficial for a myriad of potential applications. A novel design and universal approach for the fabrication of unique plasmonic g-C3N4 nanoscale hybrids, with well-controlled morphology, is presented. A single gold nanoprism is encapsulated within dense or hollow g-C3N4 spheres for the formation of Au@g-C3N4 core-shell and Au@g-C3N4 yolk-shell nanohybrids. Au nanoprisms were chosen duo to the strong (visible range) plasmon resonances and electromagnetic field hotspots formed at their sharp corners. The incorporation of Au nanoprisms into the g-C3N4 nanospheres results in a dramatic ∼threefold rise in the emission of plasmonic g-C3N4 yolk-shell nanohybrids and ∼3.6-fold enhancement of the photocurrent density obtained from the plasmonic g-C3N4 core-shell nanohybrids, when compared with the g-C3N4 hollow nanospheres. Hence, these hybrids can potentially benefit applications in the areas spanning from solar energy harvesting to biomedical imaging and theranostics.
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Affiliation(s)
- Firdoz Shaik
- Schulich Faculty of Chemistry, Technion─Israel Institute of Technology, Haifa 32000, Israel
| | - Riccardo Milan
- Schulich Faculty of Chemistry, Technion─Israel Institute of Technology, Haifa 32000, Israel
| | - Lilac Amirav
- Schulich Faculty of Chemistry, Technion─Israel Institute of Technology, Haifa 32000, Israel
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Dong K, Pezzetta C, Chen QC, Kaushansky A, Agosti A, Bergamini G, Davidson R, Amirav L. Nanorod Photocatalysts For C‐O Cross‐coupling Reactions. ChemCatChem 2022. [DOI: 10.1002/cctc.202200477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Kaituo Dong
- Technion Israel Institute of Technology chemistry ISRAEL
| | | | - Qiu-Cheng Chen
- Technion Israel Institute of Technology chemistry ISRAEL
| | | | | | | | | | - Lilac Amirav
- Technion – Israel Institute of Technology Schulich Faculty of Chemistry Technion 3200008 Haifa ISRAEL
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11
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Xing Z, Dong K, Pavlopoulos N, Chen Y, Amirav L. Photoinduced Self-Assembly of Carbon Nitride Quantum Dots. Angew Chem Int Ed Engl 2021; 60:19413-19418. [PMID: 34133052 DOI: 10.1002/anie.202107079] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Indexed: 11/09/2022]
Abstract
The study of nanocrystal self-assembly into superlattices or superstructures is of great significance in nanoscience. Carbon nitride quantum dots (CNQDs), being a promising new group of nanomaterials, however, have hardly been explored in their self-organizing behavior. Here we report of a unique irradiation-triggered self-assembly and recrystallization phenomenon of crystalline CNQDs (c-CNQDs) terminated by abundant oxygen-containing groups. Unlike the conventional self-assembly of nanocrystals into ordered superstructures, the photoinduced self-assembly of c-CNQDs resembles a "click reaction" process of macromolecules, in which the activated -OH and -NH2 functional groups along the perimeters initiate cross-linking of adjacent QDs through a photocatalytic effect. Our findings unveil fundamental physiochemical features of CNQDs and open up new possibilities of manipulating carbon nitride nanomaterials via controlled assembly. Prospects for potential applications are discussed as well.
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Affiliation(s)
- Zheng Xing
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion city, Haifa, Israel
| | - Kaituo Dong
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion city, Haifa, Israel
| | - Nick Pavlopoulos
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion city, Haifa, Israel
| | - Yuexing Chen
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion city, Haifa, Israel
| | - Lilac Amirav
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Technion city, Haifa, Israel
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12
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Affiliation(s)
- Zheng Xing
- Schulich Faculty of Chemistry Technion-Israel Institute of Technology, Technion city Haifa Israel
| | - Kaituo Dong
- Schulich Faculty of Chemistry Technion-Israel Institute of Technology, Technion city Haifa Israel
| | - Nick Pavlopoulos
- Schulich Faculty of Chemistry Technion-Israel Institute of Technology, Technion city Haifa Israel
| | - Yuexing Chen
- Schulich Faculty of Chemistry Technion-Israel Institute of Technology, Technion city Haifa Israel
| | - Lilac Amirav
- Schulich Faculty of Chemistry Technion-Israel Institute of Technology, Technion city Haifa Israel
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13
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Agosti A, Natali M, Amirav L, Bergamini G. Towards Solar Factories: Prospects of Solar-to-Chemical Energy Conversion using Colloidal Semiconductor Photosynthetic Systems. ChemSusChem 2020; 13:4894-4899. [PMID: 32809266 DOI: 10.1002/cssc.202001274] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/12/2020] [Indexed: 05/25/2023]
Abstract
Solar-to-chemical (STC) energy conversion is the fundamental process that nurtures Earth's ecosystem, fixing the inexhaustible solar resource into chemical bonds. Photochemical synthesis endows plants with the primary substances for their development; likewise, an artificial mimic of natural systems has long sought to support human civilization in a sustainable way. Intensive efforts have demonstrated light-triggered production of different solar fuels, such as H2 , CO, CH4 and NH3 , while research on oxidative half-reactions has built up from O2 generation to organic synthesis, waste degradation and photo-reforming. Nevertheless, while extensive utilization of the radiant chemical potential to promote a manifold of endergonic processes is the common thread of such research, exploration of the chemical space is fragmented by the lack of a common language across different scientific disciplines. Focusing on colloidal semiconductor materials, this Viewpoint discusses an inclusive protocol for the discovery and assessment of STC redox reactions, aiming to establish photon-to-molecule conversion as the ultimate paradigm beyond fossil energy exploitation.
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Affiliation(s)
- Amedeo Agosti
- Chemistry Department "Giacomo Ciamician", University of Bologna, Via F. Selmi 2, 40129, Bologna, Italy
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, 32000, Haifa, Israel
| | - Mirco Natali
- Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Via L. Borsari 46, 44121, Ferrara, Italy
- Centro Interuniversitario per la Conversione Chimica dell'Energia Solare (SolarChem), sez. di Ferrara, Via L. Borsari 46, 44121, Ferrara, Italy
| | - Lilac Amirav
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, 32000, Haifa, Israel
| | - Giacomo Bergamini
- Chemistry Department "Giacomo Ciamician", University of Bologna, Via F. Selmi 2, 40129, Bologna, Italy
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Abstract
The development of imaging methodologies for single cell measurements over extended timescales of up to weeks, in the intact animal, will depend on signal strength, stability, validity and specificity of labeling. Whereas light-microscopy can achieve these with genetically-encoded probes or dyes, this modality does not allow mesoscale imaging of entire intact tissues. Non-invasive imaging techniques, such as magnetic resonance imaging (MRI), outperform light microscopy in field of view and depth of imaging, but do not offer cellular resolution and specificity, suffer from low signal-to-noise ratio and, in some instances, low temporal resolution. In addition, the origins of the signals measured by MRI are either indirect to the process of interest or hard to validate. It is therefore highly warranted to find means to enhance MRI signals to allow increases in resolution and cellular-specificity. To this end, cell-selective bi-functional magneto-fluorescent contrast agents can provide an elegant solution. Fluorescence provides means for identification of labeled cells and particles location after MRI acquisition, and it can be used to facilitate the design of cell-selective labeling of defined targets. Here we briefly review recent available designs of magneto-fluorescent markers and elaborate on key differences between them with respect to durability and relevant cellular highlighting approaches. We further focus on the potential of intracellular labeling and basic functional sensing MRI, with assays that enable imaging cells at microscopic and mesoscopic scales. Finally, we illustrate the qualities and limitations of the available imaging markers and discuss prospects for in vivo neural imaging and large-scale brain mapping.
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Affiliation(s)
- Lilac Amirav
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
| | - Shai Berlin
- Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Shunit Olszakier
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel.,Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Sandip K Pahari
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel
| | - Itamar Kahn
- Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
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15
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Abstract
Conversion of solar energy into liquid fuel often relies on multielectron redox processes that include highly reactive intermediates, with back reaction routes that hinder the overall efficiency of the process. Here, we reveal that these undesirable reaction pathways can be minimized, rendering the photocatalytic reactions more efficient, when charge carriers are harvested from a multiexcitonic state of a semiconductor photocatalyst. A plasmonic antenna, comprising Au nanoprisms, was employed to accomplish feasible levels of multiple carrier excitations in semiconductor nanocrystal-based photocatalytic systems (CdSe@CdS core-shell quantum dots and CdSe@CdS seeded nanorods). The antenna's near-field amplifies the otherwise inherently weak biexciton generation in the semiconductor. The two-electron photoreduction of Pt and Pd metal precursors served as model reactions. In the presence of the plasmonic antenna, these photocatalyzed two-electron reactions exhibited enhanced yields and kinetics. This work uniquely relies on a nonlinear enhancement that has potential for large amplification of photocatalytic activity in the presence of a plasmonic near-field.
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Affiliation(s)
- Firdoz Shaik
- Schulich Faculty of Chemistry , Technion-Israel Institute of Technology , Haifa 32000 , Israel
| | - Imanuel Peer
- Schulich Faculty of Chemistry , Technion-Israel Institute of Technology , Haifa 32000 , Israel
| | - Prashant K Jain
- Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Lilac Amirav
- Schulich Faculty of Chemistry , Technion-Israel Institute of Technology , Haifa 32000 , Israel
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16
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Nakibli Y, Mazal Y, Dubi Y, Wächtler M, Amirav L. Size Matters: Cocatalyst Size Effect on Charge Transfer and Photocatalytic Activity. Nano Lett 2018; 18:357-364. [PMID: 29236508 DOI: 10.1021/acs.nanolett.7b04210] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Hybrid semiconductor-metallic nanostructures play an important role in a wide range of applications and are key components in photocatalysis. Here we reveal that the nature of a nanojunction formed between a semiconductor nanorod and metal nanoparticle is sensitive to the size of the metal component. This is reflected in the activity toward hydrogen production, emission quantum yields, and the efficiency of charge separation which is determined by transient absorption spectroscopy. A set of Ni decorated CdSe@CdS nanorods with different tip size were examined, and an optimal metal domain size of 5.2 nm was obtained. Remarkably, charge separation time constants were found to be nonvariant with metal tip size. It is proposed that electron transfer mechanism encompasses two consecutive but separate processes: slow charge migration along the rod toward the interface, followed by fast interface crossing of the electron from the semiconductor into the metal phase. The first migration step dominates the time constant for the charge separation process and is not affected by the metal size. The efficiency of charge separation on the other hand was found to be sensitive to metal size. It is suggested that Coulomb blockade charging energy and a size-dependent Schottky barrier contribute to the metal size effect on charge transfer probability across the semiconductor-metal nanojunction. These two opposing trends result in an optimal metal size domain for the cocatalyst. This work is expected to benefit a broad range of applications utilizing semiconductor-metal nanocomposites.
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Affiliation(s)
- Yifat Nakibli
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology , Haifa 32000, Israel
| | - Yair Mazal
- Department of Chemistry and the Ilse Katz center for Nanoscale Science and Technology, Ben-Gurion University of the Negev , Beer-Sheva 8410501, Israel
| | - Yonatan Dubi
- Department of Chemistry and the Ilse Katz center for Nanoscale Science and Technology, Ben-Gurion University of the Negev , Beer-Sheva 8410501, Israel
| | - Maria Wächtler
- Department Functional Interfaces, Leibniz Institute of Photonic Technology Jena , Albert-Einstein-Straße 9, 07745 Jena, Germany
| | - Lilac Amirav
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology , Haifa 32000, Israel
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17
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Abstract
We report a record 100% photon-to-hydrogen production efficiency, under visible light illumination, for the photocatalytic water-splitting reduction half-reaction. This result was accomplished by utilization of nanoparticle-based photocatalysts, composed of Pt-tipped CdSe@CdS rods, with a hydroxyl anion-radical redox couple operating as a shuttle to relay the holes. The implications of such record efficiency for the prospects of realizing practical over all water splitting and solar-to-fuel energy conversion are discussed.
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Affiliation(s)
- Philip Kalisman
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology , Haifa 32000, Israel
| | - Yifat Nakibli
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology , Haifa 32000, Israel
| | - Lilac Amirav
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology , Haifa 32000, Israel
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18
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Abstract
We demonstrate a procedure for the photochemical oxidative growth of iridium oxide catalysts on the surface of seeded cadmium selenide-cadmium sulfide (CdSe@CdS) nanorod photocatalysts. Seeded rods are grown using a colloidal hot-injection method and then moved to an aqueous medium by ligand exchange. CdSe@CdS nanorods, an iridium precursor and other salts are mixed and illuminated. The deposition process is initiated by absorption of photons by the semiconductor particle, which results with formation of charge carriers that are used to promote redox reactions. To insure photochemical oxidative growth we used an electron scavenger. The photogenerated holes oxidize the iridium precursor, apparently in a mediated oxidative pathway. This results in the growth of high quality crystalline iridium oxide particles, ranging from 0.5 nm to about 3 nm, along the surface of the rod. Iridium oxide grown on CdSe@CdS heterostructures was studied by a variety of characterization methods, in order to evaluate its characteristics and quality. We explored means for control over particle size, crystallinity, deposition location on the CdS rod, and composition. Illumination time and excitation wavelength were found to be key parameters for such control. The influence of different growth conditions and the characterization of these heterostructures are described alongside a detailed description of their synthesis. Of significance is the fact that the addition of iridium oxide afforded the rods astounding photochemical stability under prolonged illumination in pure water (alleviating the requirement for hole scavengers).
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Affiliation(s)
- Philip Kalisman
- Schulich Faculty of Chemistry, The Russell Berrie Nanotechnology Institute, The Nancy and Stephen Grand Technion Energy Program, Technion - Israel Institute of Technology
| | - Yifat Nakibli
- Schulich Faculty of Chemistry, The Russell Berrie Nanotechnology Institute, The Nancy and Stephen Grand Technion Energy Program, Technion - Israel Institute of Technology
| | - Lilac Amirav
- Schulich Faculty of Chemistry, The Russell Berrie Nanotechnology Institute, The Nancy and Stephen Grand Technion Energy Program, Technion - Israel Institute of Technology;
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19
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Abstract
The enhanced catalytic properties of bimetallic particles has made them the focus of extensive research. We compare the photocatalytic activity for hydrogen production of core-shell structures of Au@Pd and Au@(Au/Pd alloy) on seeded rods of CdSe@CdS and show that Au@alloy was superior toward hydrogen production. Our finding reveals that the promotion effects of Au in Pd originate both from the alteration of the electronic structure by the Au core as well as by the atomic rearrangement of the surface. Long-term monitoring of the activity of the photocatalysts offered insights into the dynamic processes during the illumination showing that the tip morphology influenced the stability of the hybrid structures. The Au core served as a physical barrier, protecting the CdS rod against cation exchange reactions with the Pd. The coupling of these factors to achieve synergistic effects is therefore a prime aspect in the rational design of efficient cocatalysts.
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Affiliation(s)
- Eran Aronovitch
- Department of Chemistry, Ben-Gurion University of the Negev , Beer-Sheva 8410501, Israel
| | - Philip Kalisman
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology , Haifa 32000, Israel
| | - Shai Mangel
- Department of Chemistry, Ben-Gurion University of the Negev , Beer-Sheva 8410501, Israel
| | - Lothar Houben
- Peter Grünberg Institut 5 and Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH , 52425 Jülich, Germany
| | - Lilac Amirav
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology , Haifa 32000, Israel
| | - Maya Bar-Sadan
- Department of Chemistry, Ben-Gurion University of the Negev , Beer-Sheva 8410501, Israel
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20
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Abstract
We provide evidence that for a multielectron reaction such as hydrogen reduction, the photocatalyst design should include only a single cocatalytic site per each segment of the semiconductor capable of light excitation. This is to ensure that intermediates are formed at close proximity. These findings are demonstrated by evaluating the efficiency for hydrogen production over a nanoparticle-based photocatalyst consisting of Pt-decorated CdSe@CdS rods. Rods decorated with a single Pt catalyst were found to be the most active for hydrogen production, with QE of 27%, while rods having two reduction sites reached QE of only 18% and rods with multiple sites showed very low activity. The advantage of using a single catalytic site became negligible when the rods were employed in catalyzing a single electron reaction. We believe the implications of this finding are of significance for the proper design of photocatalysts aimed at solar-to-fuel energy conversion.
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Affiliation(s)
- Yifat Nakibli
- Schulich Faculty of Chemistry, The Russell Berrie Nanotechnology Institute, and The Nancy and Stephen Grand Technion Energy Program; Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Philip Kalisman
- Schulich Faculty of Chemistry, The Russell Berrie Nanotechnology Institute, and The Nancy and Stephen Grand Technion Energy Program; Technion - Israel Institute of Technology, Haifa 3200003, Israel
| | - Lilac Amirav
- Schulich Faculty of Chemistry, The Russell Berrie Nanotechnology Institute, and The Nancy and Stephen Grand Technion Energy Program; Technion - Israel Institute of Technology, Haifa 3200003, Israel
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21
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22
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Amirav L, Oba F, Aloni S, Alivisatos AP. Modular Synthesis of a Dual Metal-Dual Semiconductor Nano-Heterostructure. Angew Chem Int Ed Engl 2015; 54:7007-11. [DOI: 10.1002/anie.201411461] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 02/19/2015] [Indexed: 11/08/2022]
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23
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Amirav L, Lifshitz E. A Spray-Based Technique for the Production of MnS Thin Films. Chemphyschem 2014; 16:353-9. [DOI: 10.1002/cphc.201402645] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 10/12/2014] [Indexed: 11/06/2022]
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24
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Affiliation(s)
- Lilac Amirav
- Department
of Chemistry, University of California at Berkeley, and Materials Science Division,
Lawrence Berkeley National Laboratory, Berkeley, California 94720,
United States
| | - A. Paul Alivisatos
- Department
of Chemistry, University of California at Berkeley, and Materials Science Division,
Lawrence Berkeley National Laboratory, Berkeley, California 94720,
United States
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25
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Tang ML, Grauer DC, Lassalle-Kaiser B, Yachandra VK, Amirav L, Long JR, Yano J, Alivisatos AP. Structural and Electronic Study of an Amorphous MoS3 Hydrogen-Generation Catalyst on a Quantum-Controlled Photosensitizer. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201104412] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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26
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Affiliation(s)
- Prashant K. Jain
- Department of Chemistry, University of California, Berkeley California 94720, Miller Institute for Basic Research in Science, University of California, Berkeley, California 94720, Materials Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Lilac Amirav
- Department of Chemistry, University of California, Berkeley California 94720, Miller Institute for Basic Research in Science, University of California, Berkeley, California 94720, Materials Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Shaul Aloni
- Department of Chemistry, University of California, Berkeley California 94720, Miller Institute for Basic Research in Science, University of California, Berkeley, California 94720, Materials Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - A. Paul Alivisatos
- Department of Chemistry, University of California, Berkeley California 94720, Miller Institute for Basic Research in Science, University of California, Berkeley, California 94720, Materials Research Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720
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27
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Abstract
A novel spray-based technique enables the production of high-quality, free, uncoated semiconductor nanocrystals. Their collection, following spray droplet desolvation during flight, could result in unusual structures. We report on spray-produced ordered clusters (approximately 50 nm diameter) of MnS nanocrystals with grain size range of 1-2 nm and their assembly into micron-sized coral-shaped fractal aggregates. Ballistic cluster-particle aggregation, with the introduction of physical interaction between particles, is suggested as a model for the assemblies' growth.
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Affiliation(s)
- Lilac Amirav
- Department of Chemistry, Solid State Institute, Haifa 32000, Israel
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28
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Kigel A, Brumer M, Sashchiuk A, Amirav L, Lifshitz E. PbSe/PbSexS1−x core-alloyed shell nanocrystals. Materials Science and Engineering: C 2005. [DOI: 10.1016/j.msec.2005.06.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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29
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Osovsky R, Shavel A, Gaponik N, Amirav L, Eychmüller A, Weller H, Lifshitz E. Electrostatic and Covalent Interactions in CdTe Nanocrystalline Assemblies. J Phys Chem B 2005; 109:20244-50. [PMID: 16853618 DOI: 10.1021/jp0526795] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper focuses on the interactions between cysteamine-stabilized CdTe nanocrystals [CdTe(CA) NCs] and thioglycolic-acid-stabilized CdTe nanocrystals [CdTe(TGA) NCs]. These interactions were examined by the absorption, continuous, and time-resolved photoluminescence (PL) spectra of the electrostatically mixed and the covalently linked NCs assemblies comprised of the oppositely surface charged CdTe(CA) and CdTe(TGA) NCs and by a comparison with those of the corresponding pristine NCs. The CdTe(CA)-CdTe(TGA) coupling is dictated by the surfactant spacer, ranging between 0.93 and 1.14 nm and by electrostatic and covalent interactions, enabling a Förster resonance energy transfer (FRET) process among the NCs. The results revealed an excellent spectral overlap between the emission of the CdTe(TGA) NCs and the absorption of the CdTe(CA) NCs as well as a PL spectral red shift on the formation of electrostatic and covalent interactions. Furthermore, the measurements showed a lifetime ranging between 1.2 and 3 ns for the electrostatically mixed and the covalently linked assemblies, shorter than those of the pristine CdTe(CA) NCs and CdTe(TGA) NCs, both of which measured as approximately 5.5 ns. When CdTe(TGA) NCs performed as the most efficient donors, FRET rates of 10(10)-10(11) s(-1) were calculated for the electrostatically mixed NCs or covalently linked NCs.
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Affiliation(s)
- Ruth Osovsky
- Department of Chemistry and Solid State Institute and the Russell Berrie Nanotechnology Institute, Technion, Haifa 32000, Israel.
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30
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Abstract
We present a spray based-method for the formation and production of semiconductor nanocrystals that provides an attractive alternative to the commonly used epitaxial and colloidal procedures. According to this spray-based method, mainly thermospray, solutions of semiconductor salts are first sprayed into monodispersed droplets, which subsequently become solid nanocrystals by solvent evaporation. A semiconductor nanocrystal is produced from a single spray droplet upon the full vaporization of the solvent. The average diameter and size distribution of the final nanocrystals are controlled and determined by the solute concentration of the sprayed solution and by the droplet size, hence by the spray production parameters. The spray-produced nanocrystals are collected on any selected solid support. Representative results, shown in this letter, reveal the formation of CdS nanocrystals in the size range of 3 to 6 nanometers and with a size distribution of as low as five percent. A further structural analysis of these nanocrystals showed that they were formed in the zinc blend phase with a high degree of crystallinity.
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