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Su J, Ji Y, Geng S, Li L, Liu D, Yu H, Song B, Li Y, Pao CW, Hu Z, Huang X, Lu J, Shao Q. Core-Shell Design of Metastable Phase Catalyst Enables Highly-Performance Selective Hydrogenation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2308839. [PMID: 37906727 DOI: 10.1002/adma.202308839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/20/2023] [Indexed: 11/02/2023]
Abstract
Highly selective semihydrogenation of alkynes to alkenes is a highly important reaction for catalytic industry. Developing non-noble metal based catalysts with platinum group metal-like activity and selectivity is extremely crucial yet challenging. Metastable phase catalysts provide a potential candidate to realize high activity, yet the control of selectivity remains an open question. Here, this work first reports a metastable phase core-shell: face-centered cubic (fcc) phase Ag (10 at%) core-metastable hexagonal closest packed (hcp) phase Ni (90 at%) shell catalyst, which represents high conversion rate, high selectivity, and remarkable universality for the semihydrogenation of phenylacetylene and its derivatives. More impressively, a turnover frequency (TOF) value of 8241.8 h-1 is achieved, much higher than those of stable phase catalysts and reported platinum group metal based catalysts. Mechanistic investigation reveals that the surface of hcp Ni becomes more oxidized due to electron transfer from hcp Ni shell to fcc Ag core, which decreases the adsorption capacity of styrene on the metastable phase Ni surface, thus preventing full hydrogenation. This work has gained crucial research significance for the design of high performance metastable phase catalysts.
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Affiliation(s)
- Jiaqi Su
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Jiangsu, 215123, China
| | - Yujin Ji
- Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Jiangsu, 215123, China
| | - Shize Geng
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Jiangsu, 215123, China
| | - Lamei Li
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Jiangsu, 215123, China
| | - Da Liu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Jiangsu, 215123, China
| | - Hao Yu
- Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Jiangsu, 215123, China
| | - Beibei Song
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Jiangsu, 215123, China
| | - Youyong Li
- Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Jiangsu, 215123, China
| | - Chih-Wen Pao
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu, 30076, Taiwan
| | - Zhiwei Hu
- Max Planck Institute for Chemical Physics of Solids, Nothnitzer Strasse 40, 01187, Dresden, Germany
| | - Xiaoqing Huang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Jianmei Lu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Jiangsu, 215123, China
| | - Qi Shao
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Jiangsu, 215123, China
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2
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Marri I, Grillo S, Amato M, Ossicini S, Pulci O. Interplay of Quantum Confinement and Strain Effects in Type I to Type II Transition in GeSi Core-Shell Nanocrystals. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:1209-1219. [PMID: 36704663 PMCID: PMC9869394 DOI: 10.1021/acs.jpcc.2c07024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 12/14/2022] [Indexed: 06/18/2023]
Abstract
The electronic properties of hydrogenated, spherical SiGe and GeSi core-shell nanocrystals, with a diameter ranging from 1.8 to 4.0 nm, are studied within density functional theory. Effects induced by quantum confinement and strain on the near-band-edge state localization, as well as the band-offset properties between Si and Ge regions, are investigated in detail. On the one hand, we prove that SiGe core-shell nanocrystals always show a type II band-offset alignment, with the HOMO mainly localized on the Ge shell region and the LUMO mainly localized on the Si core region. On the other hand, our results point out that a type II offset cannot be observed in small (diameter less than 3 nm) GeSi core-shell nanocrystals. In these systems, quantum confinement and strain drive the near-band-edge states to be mainly localized on Ge atoms, i.e., in the core region. In larger GeSi core-shell nanocrystals, instead, the formation of a type II offset can be engineered by playing with both core and shell thickness. The factors which determine the band-offset character at the Ge/Si interface are discussed in detail.
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Affiliation(s)
- Ivan Marri
- Department
of Sciences and Methods for Engineering, University of Modena and Reggio Emilia, 42122 Reggio Emilia, Italy
- Interdepartmental
Center for Research and Services in the Field of Hydrogen Production,
Storage and Use H2 − MO.RE, Via Università 4, 41121 Modena, Italy
- Centro
Interdipartimentale En&Tech, 42122 Reggio Emilia, Italy
| | - Simone Grillo
- Department
of Physics, University of Rome Tor Vergata,
and INFN, Via della Ricerca Scientifica 1, I-00133 Rome, Italy
| | - Michele Amato
- Université
Paris-Saclay, CNRS, Laboratoire de Physique
des Solides, 91405 Orsay, France
| | - Stefano Ossicini
- Department
of Sciences and Methods for Engineering, University of Modena and Reggio Emilia, 42122 Reggio Emilia, Italy
- Centro
Interdipartimentale En&Tech, 42122 Reggio Emilia, Italy
- Centro
S3, Institute of Nanoscience — Italian National Research Council
(CNR-NANO), via Campi
213/A, 41125 Modena, Italy
| | - Olivia Pulci
- Department
of Physics, University of Rome Tor Vergata,
and INFN, Via della Ricerca Scientifica 1, I-00133 Rome, Italy
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3
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Sawahreh A, Binyamin T, Jiang J, Millo O, Goldberg O, Azulay D, Pachter R, Etgar L. Electrical and chemical properties of vacancy-ordered lead free layered double perovskite nanoparticles. NANOSCALE 2022; 14:3487-3495. [PMID: 35171187 DOI: 10.1039/d2nr00565d] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In this work we synthesized vacancy-ordered lead-free layered double perovskite (LDP) nanoparticles. This structure consists of two layers of trivalent metal halide octahedra [B(III)X6]3- separated by a layer of divalent metal [B(II)X6]4- (B is a divalent or trivalent metal). The chemical formula of this structure is based on A4B(II)B(III)2X12 where A is Cs, B(III) is Bi, X is Cl and B(II) is a different ratio between Mn2+ and Cd2+. Well-defined colloidal nanoplates of Cs4CdxMn1-xBi2Cl12 were successfully synthesized. These nanoplates show photoluminescence (PL) in the orange to red region that can be tuned by changing the Cd/Mn ratio. High resolution scanning transmission electron microscopy (HR-STEM) and atomic resolution elemental analysis were performed on these lead free LDP nanoplates revealing two different particle compositions that can be controlled by the Cd/Mn ratio. Ultraviolet Photoelectron Spectroscopy (UPS) and scanning tunneling spectroscopy (STS) reveal the band gap structure of these LDP nanoplates. Density functional theory (DFT) calculations show the existence of [MnCl6]4- in-gap states. While the absorption occurs from the valence band maximum (VBM) to the conduction band minimum (CBM), the emission may occur from the CBM to an in-gap band maximum (IGM), which could explain the PL in the orange to red region of these nanoplates. This work provides a detailed picture of the chemical and electronic properties of LDP nanoparticles.
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Affiliation(s)
- Amal Sawahreh
- Institute of Chemistry, Casali Center for Applied Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
| | - Tal Binyamin
- Institute of Chemistry, Casali Center for Applied Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
| | - Jie Jiang
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433, USA
| | - Oded Millo
- Racah Institute of Physics, The Hebrew University of Jerusalem and the Center for Nanoscience and Nanotechnology, Jerusalem 91904, Israel
| | - Oren Goldberg
- Racah Institute of Physics, The Hebrew University of Jerusalem and the Center for Nanoscience and Nanotechnology, Jerusalem 91904, Israel
| | - Doron Azulay
- Racah Institute of Physics, The Hebrew University of Jerusalem and the Center for Nanoscience and Nanotechnology, Jerusalem 91904, Israel
| | - Ruth Pachter
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433, USA
| | - Lioz Etgar
- Institute of Chemistry, Casali Center for Applied Chemistry and the Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
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4
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Milliken S, Cui K, Klein BA, Cheong IT, Yu H, Michaelis VK, Veinot JGC. Tailoring B-doped silicon nanocrystal surface chemistry via phosphorus pentachloride - mediated surface alkoxylation. NANOSCALE 2021; 13:18281-18292. [PMID: 34714905 DOI: 10.1039/d1nr05255a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Doped silicon nanocrystals (SiNCs) are promising materials that could find use in a wide variety of applications. Realizing methods to tailor the surface chemistry of these particles offers greater tunability of the material properties as well as broader solvent compatibility. Herein, we report organic-soluble B-doped SiNCs prepared via a thermal processing method followed by phosphorus pentachloride etching induced functionalization with alkoxy ligands of varied chain lengths. This approach provides a scalable route to solution processable B-doped SiNCs and establishes a potential avenue for the functionalization of other doped SiNCs.
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Affiliation(s)
- Sarah Milliken
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada.
| | - Kai Cui
- Nanotechnology Research Centre, National Research Council of Canada, Edmonton, T6G 1H9, AB, Canada
| | - Brittney A Klein
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada.
| | - I Teng Cheong
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada.
| | - Haoyang Yu
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada.
| | - Vladimir K Michaelis
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada.
| | - Jonathan G C Veinot
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta T6G 2G2, Canada.
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5
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Milliken S, Thiessen AN, Cheong IT, O'Connor KM, Li Z, Hooper RW, Robidillo CJT, Veinot JGC. "Turning the dials": controlling synthesis, structure, composition, and surface chemistry to tailor silicon nanoparticle properties. NANOSCALE 2021; 13:16379-16404. [PMID: 34492675 DOI: 10.1039/d1nr04701a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Silicon nanoparticles (SiNPs) can be challenging to prepare with defined size, crystallinity, composition, and surface chemistry. As is the case for any nanomaterial, controlling these parameters is essential if SiNPs are to realize their full potential in areas such as alternative energy generation and storage, sensors, and medical imaging. Numerous teams have explored and established innovative synthesis methods, as well as surface functionalization protocols to control these factors. Furthermore, substantial effort has been expended to understand how the abovementioned parameters influence material properties. In the present review we provide a commentary highlighting the benefits and limitations of available methods for preparing silicon nanoparticles as well as demonstrations of tailoring optical and electronic properties through definition of structure (i.e., crystalline vs. amorphous), composition and surface chemistry. Finally, we highlight potential opportunities for future SiNP studies.
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Affiliation(s)
- Sarah Milliken
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
| | | | - I Teng Cheong
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
| | - Kevin M O'Connor
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
| | - Ziqi Li
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
| | - Riley W Hooper
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
| | | | - Jonathan G C Veinot
- Department of Chemistry, University of Alberta, Chemistry, Edmonton, Canada.
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6
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Ji B, Rabani E, Efros AL, Vaxenburg R, Ashkenazi O, Azulay D, Banin U, Millo O. Dielectric Confinement and Excitonic Effects in Two-Dimensional Nanoplatelets. ACS NANO 2020; 14:8257-8265. [PMID: 32584026 DOI: 10.1021/acsnano.0c01950] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Quasi-two-dimensional (2D) semiconductor nanoplatelets manifest strong quantum confinement with exceptional optical characteristics of narrow photoluminescence peaks with energies tunable by thickness with monolayer precision. We employed scanning tunneling spectroscopy (STS) in conjunction with optical measurements to probe the thickness-dependent band gap and density of excited states in a series of CdSe nanoplatelets. The tunneling spectra, measured in the double-barrier tunnel junction configuration, reveal the effect of quantum confinement on the band gap taking place mainly through a blue-shift of the conduction band edge, along with a signature of 2D electronic structure intermixed with finite lateral-size and/or defects effects. The STS fundamental band gaps are larger than the optical gaps as expected from the contributions of exciton binding in the absorption, as confirmed by theoretical calculations. The calculations also point to strong valence band mixing between the light- and split-off hole levels. Strikingly, the energy difference between the heavy-hole and light-hole levels in the tunneling spectra are significantly larger than the corresponding values extracted from the absorption spectra. Possible explanations for this, including an interplay of nanoplatelet charging, dielectric confinement, and difference in exciton binding energy for light and heavy holes, are analyzed and discussed.
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Affiliation(s)
- Botao Ji
- Department of Chemistry and the Hebrew University Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University and Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Eran Rabani
- Department of Chemistry, University of California Berkeley, Berkeley, California 94720, United States
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- The Raymond and Beverly Sackler Center of Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 69978, Israel
| | - Alexander L Efros
- Center for Computational Material Science, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Roman Vaxenburg
- Howard Hughes Medical Institute, Janelia Research Campus, 19700 Helix Drive, Ashburn, Virginia 20147, United States
| | - Or Ashkenazi
- Racah Institute of Physics and the Hebrew University Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Doron Azulay
- Racah Institute of Physics and the Hebrew University Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
- Azrieli, Jerusalem College of Engineering, Jerusalem 9103501, Israel
| | - Uri Banin
- Department of Chemistry and the Hebrew University Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Oded Millo
- Racah Institute of Physics and the Hebrew University Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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7
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Zhang Y, Mandal R, Ratchford DC, Anthony R, Yeom J. Si Nanocrystals/ZnO Nanowires Hybrid Structures as Immobilized Photocatalysts for Photodegradation. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E491. [PMID: 32182770 PMCID: PMC7153658 DOI: 10.3390/nano10030491] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 02/25/2020] [Accepted: 03/04/2020] [Indexed: 11/17/2022]
Abstract
Numerous semiconductor-based hybrid nanostructures have been studied for improved photodegradation performance resulting from their broadband optical response and enhanced charge separation/transport characteristics. However, these hybrid structures often involve elements that are rare or toxic. Here, we present the synthesis and material characterization of hybrid nanostructures consisting of zinc oxide (ZnO) nanowires (NWs) and silicon nanocrystals (Si-NCs), both abundant and environmentally benign, and evaluate them for photodegradation performance under various illumination conditions. When incorporating Si-NCs into the vertically-aligned ZnO NWs immobilized on substrates, the resulting photocatalysts exhibited a narrowed band gap, i.e., more responsive to visible light, and enhanced charge separation at the interface, i.e., more reactive species produced for degradation. Consequently, the hybrid Si-NCs/ZnO-NWs displayed a superior photodegradability for methylene blue under UV and white light in comparison to the pristine ZnO NWs. Based on the optical measurements, we hypothesize the band structures of Si-NCs/ZnO-NWs and the potential mechanism for the improved photodegradability.
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Affiliation(s)
- Yaozhong Zhang
- Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48823, USA;
| | - Rajib Mandal
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI 48824, USA; (R.M.); (R.A.)
| | - Daniel C. Ratchford
- Code 6178, Chemistry Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA;
| | - Rebecca Anthony
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI 48824, USA; (R.M.); (R.A.)
| | - Junghoon Yeom
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI 48824, USA; (R.M.); (R.A.)
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8
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Pfaehler S, Angı A, Chryssikos D, Cattani-Scholz A, Rieger B, Tornow M. Space charge-limited current transport in thin films of alkyl-functionalized silicon nanocrystals. NANOTECHNOLOGY 2019; 30:395201. [PMID: 31304917 DOI: 10.1088/1361-6528/ab2c28] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We describe the fabrication and electrical characterization of all-silicon electrode devices to study the electronic properties of thin films of silicon nanocrystals (SiNCs). Planar, highly doped Si electrodes with contact separation of 200 nm were fabricated from silicon-on-insulator substrates, by combination of electron beam lithography and reactive ion etching. The gaps between the electrodes of height 110 nm were filled with thin-films of hexyl functionalized SiNCs (diameter 3 nm) from colloidal dispersions, via a pressure-transducing PDMS (polydimethylsiloxane) membrane. This novel approach allowed the formation of homogeneous SiNC films with precise control of their thickness in the range of 15-90 nm, practically without any voids or cracks. The measured conductance of the highly resistive SiNC films at high bias voltages up to 60 V scaled approximately linearly with gap width (5-50 μm) and gap filling height, with little device-to-device variance. We attribute the observed, pronounced hysteretic current-voltage (I-V) characteristics to space-charge-limited current transport, which-after about twenty cycles-eventually blocks the current almost completely. We propose our all-silicon device scheme and gap filling methodology as a platform to investigate charge transport in novel hybrid materials at the nanoscale, in particular in the high resistivity regime.
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Affiliation(s)
- Simon Pfaehler
- Molecular Electronics, Technische Universität München, Theresienstr. 90, D-80333 München, Germany
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9
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Kabashin AV, Singh A, Swihart MT, Zavestovskaya IN, Prasad PN. Laser-Processed Nanosilicon: A Multifunctional Nanomaterial for Energy and Healthcare. ACS NANO 2019; 13:9841-9867. [PMID: 31490658 DOI: 10.1021/acsnano.9b04610] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This review describes promising laser-based approaches to produce silicon nanostructures, including laser ablation of solid Si targets in residual gases and liquids and laser pyrolysis of silane. These methods are different from, and complementary to, widely used porous silicon technology and alternative synthesis routes. One can use these methods to make stable colloidal dispersions of silicon nanoparticles in both organic and aqueous media, which are suitable for a multitude of applications across the important fields of energy and healthcare. Size tailoring allows production of Si quantum dots with efficient photoluminescence that can be tuned across a broad spectral range from the visible to near-IR by varying particle size and surface functionalization. These nanoparticles can also be integrated with other nanomaterials to make multifunctional composites incorporating magnetic and/or plasmonic components. In the energy domain, this review highlights applications to photovoltaics and photodetectors, nanostructured silicon anodes for lithium ion batteries, and hydrogen generation from water. Application to nanobiophotonics and nanomedicine profits from the excellent biocompatibility and biodegradability of nanosilicon. These applications encompass several types of bioimaging and various therapies, including photodynamic therapy, RF thermal therapy, and radiotherapy. The review concludes with a discussion of challenges and opportunities in the applications of laser-processed nanosilicon.
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Affiliation(s)
- Andrei V Kabashin
- Aix-Marseille Univ , CNRS, LP3, Marseille 13288 , France
- MEPhI, Institute of Engineering Physics for Biomedicine (PhysBio) , 31 Kashirskoe sh. , 115409 Moscow , Russia
| | - Ajay Singh
- Institute for Lasers, Photonics, and Biophotonics , University at Buffalo, The State University of New York , Buffalo , New York 14260-3000 , United States
| | - Mark T Swihart
- Institute for Lasers, Photonics, and Biophotonics , University at Buffalo, The State University of New York , Buffalo , New York 14260-3000 , United States
- Department of Chemical and Biological Engineering and RENEW Institute , University at Buffalo, The State University of New York , Buffalo , New York 14260-4200 , United States
| | - Irina N Zavestovskaya
- MEPhI, Institute of Engineering Physics for Biomedicine (PhysBio) , 31 Kashirskoe sh. , 115409 Moscow , Russia
| | - Paras N Prasad
- MEPhI, Institute of Engineering Physics for Biomedicine (PhysBio) , 31 Kashirskoe sh. , 115409 Moscow , Russia
- Institute for Lasers, Photonics, and Biophotonics , University at Buffalo, The State University of New York , Buffalo , New York 14260-3000 , United States
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10
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Zhang YX, Wu WS, Hao HL, Shen WZ. Femtosecond laser-induced size reduction and emission quantum yield enhancement of colloidal silicon nanocrystals: effect of laser ablation time. NANOTECHNOLOGY 2018; 29:365706. [PMID: 29916813 DOI: 10.1088/1361-6528/aacd75] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Colloidal silicon (Si) nanocrystals (NCs) with different sizes were successfully prepared by femtosecond laser ablation under different laser ablation time (LAT). The mean size decreases from 4.23 to 1.42 nm by increasing the LAT from 30 to 120 min. In combination with structural characterization, temperature-dependent photoluminescence (PL), time-resolved PL and PL excitation spectra, we attribute room-temperature blue emissions peaked at 405 and 430 nm to the radiative recombination of electron-hole pairs via the oxygen-deficient centers related to Si-C-H2 and Si-O-Si bonds of colloidal Si NCs prepared in 1-octene, respectively. In particular, the measured PL quantum yield of colloidal Si NCs has been enhanced significantly from 23.6% to 55.8% by prolonging the LAT from 30 to 120 min.
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Affiliation(s)
- Y X Zhang
- College of Material Engineering, Shanghai University of Engineering Science, 333 Long Teng Road, Shanghai 201620, People's Republic of China
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11
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Angı A, Sinelnikov R, Heenen HH, Meldrum A, Veinot JGC, Scheurer C, Reuter K, Ashkenazy O, Azulay D, Balberg I, Millo O, Rieger B. The influence of conjugated alkynyl(aryl) surface groups on the optical properties of silicon nanocrystals: photoluminescence through in-gap states. NANOTECHNOLOGY 2018; 29:355705. [PMID: 29862985 DOI: 10.1088/1361-6528/aac9ef] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Developing new methods, other than size and shape, for controlling the optoelectronic properties of semiconductor nanocrystals is a highly desired target. Here we demonstrate that the photoluminescence (PL) of silicon nanocrystals (SiNCs) can be tuned in the range 685-800 nm solely via surface functionalization with alkynyl(aryl) (phenylacetylene, 2-ethynylnaphthalene, 2-ethynyl-5-hexylthiophene) surface groups. Scanning tunneling microscopy/spectroscopy on single nanocrystals revealed the formation of new in-gap states adjacent to the conduction band edge of the functionalized SiNCs. PL red-shifts were attributed to emission through these in-gap states, which reduce the effective band gap for the electron-hole recombination process. The observed in-gap states can be associated with new interface states formed via (-Si-C≡C-) bonds in combination with conjugated molecules as indicated by ab initio calculations. In contrast to alkynyl(aryl)s, the formation of in-gap states and shifts in PL maximum of the SiNCs were not observed with aryl (phenyl, naphthalene, 2-hexylthiophene) and alkynyl (1-dodecyne) surface groups. These outcomes show that surface functionalization with alkynyl(aryl) molecules is a valuable tool to control the electronic structure and optical properties of SiNCs via tuneable interface states, which may enhance the performance of SiNCs in semiconductor devices.
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Affiliation(s)
- Arzu Angı
- WACKER-Lehrstuhl für Makromolekulare Chemie, Technische Universität München, Lichtenbergstraße 4, D-85747, Germany. Catalysis Research Center, Ernst-Otto-Fischer-Straße 1, D-85748 Garching, Germany
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12
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Grötsch RK, Angı A, Mideksa YG, Wanzke C, Tena-Solsona M, Feige MJ, Rieger B, Boekhoven J. Dissipative Selbstassemblierung photolumineszierender Siliciumnanokristalle. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201807937] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Raphael K. Grötsch
- Fakultät für Chemie; Technische Universität München; Lichtenbergstraße 4 85748 Garching Deutschland
- Institute for Advanced Study; Technische Universität München; Lichtenbergstraße 2a 85748 Garching Deutschland
| | - Arzu Angı
- WACKER-Lehrstuhl für Makromolekulare Chemie; Technische Universität München; Deutschland
- Zentralinstitut für Katalyseforschung; Garching Deutschland
| | - Yonatan G. Mideksa
- Center for Integrated Protein Science an der Fakultät für Chemie; Technische Universität München; Garching Deutschland
- Institute for Advanced Study; Technische Universität München; Lichtenbergstraße 2a 85748 Garching Deutschland
| | - Caren Wanzke
- Fakultät für Chemie; Technische Universität München; Lichtenbergstraße 4 85748 Garching Deutschland
- Institute for Advanced Study; Technische Universität München; Lichtenbergstraße 2a 85748 Garching Deutschland
| | - Marta Tena-Solsona
- Fakultät für Chemie; Technische Universität München; Lichtenbergstraße 4 85748 Garching Deutschland
- Institute for Advanced Study; Technische Universität München; Lichtenbergstraße 2a 85748 Garching Deutschland
| | - Matthias J. Feige
- Center for Integrated Protein Science an der Fakultät für Chemie; Technische Universität München; Garching Deutschland
- Institute for Advanced Study; Technische Universität München; Lichtenbergstraße 2a 85748 Garching Deutschland
| | - Bernhard Rieger
- WACKER-Lehrstuhl für Makromolekulare Chemie; Technische Universität München; Deutschland
- Zentralinstitut für Katalyseforschung; Garching Deutschland
| | - Job Boekhoven
- Fakultät für Chemie; Technische Universität München; Lichtenbergstraße 4 85748 Garching Deutschland
- Institute for Advanced Study; Technische Universität München; Lichtenbergstraße 2a 85748 Garching Deutschland
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13
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Grötsch RK, Angı A, Mideksa YG, Wanzke C, Tena-Solsona M, Feige MJ, Rieger B, Boekhoven J. Dissipative Self-Assembly of Photoluminescent Silicon Nanocrystals. Angew Chem Int Ed Engl 2018; 57:14608-14612. [PMID: 30040877 DOI: 10.1002/anie.201807937] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Indexed: 12/12/2022]
Abstract
Solutions of silicon nanocrystals (SiNCs) are used in a diverse range of applications because of their tunable photoluminescence, biocompatibility, and the abundance of Si. In dissipative supramolecular materials, self-assembly of molecules or nanoparticles is driven by a chemical reaction network that irreversible consumes fuel. The properties of the emerging structures are controlled by the kinetics of the underlying chemical reaction network. Herein, we demonstrate the dissipative self-assembly of photoluminescent SiNCs driven by a chemical fuel. A chemical reaction induces self-assembly of the water-soluble SiNCs. However, the assemblies are transient, and when the chemical reaction network runs out of fuel, the SiNCs disassemble. The lifetime of the assemblies is controlled by the amount of fuel added. As an application of the transient supramolecular material, we demonstrate that the platform can be used to control the delayed uptake of the nanocrystals by mammalian cells.
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Affiliation(s)
- Raphael K Grötsch
- Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85748, Garching, Germany.,Institute for Advanced Study, Technische Universität München, Lichtenbergstrasse 2a, 85748, Garching, Germany
| | - Arzu Angı
- WACKER-Lehrstuhl für Makromolekulare Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748, Garching, Germany.,Catalysis Research Center, Ernst-Otto-Fischer-Strasse 1, 85748, Garching, Germany
| | - Yonatan G Mideksa
- Center for Integrated Protein Science at the Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85748, Garching, Germany.,Institute for Advanced Study, Technische Universität München, Lichtenbergstrasse 2a, 85748, Garching, Germany
| | - Caren Wanzke
- Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85748, Garching, Germany.,Institute for Advanced Study, Technische Universität München, Lichtenbergstrasse 2a, 85748, Garching, Germany
| | - Marta Tena-Solsona
- Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85748, Garching, Germany.,Institute for Advanced Study, Technische Universität München, Lichtenbergstrasse 2a, 85748, Garching, Germany
| | - Matthias J Feige
- Center for Integrated Protein Science at the Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85748, Garching, Germany.,Institute for Advanced Study, Technische Universität München, Lichtenbergstrasse 2a, 85748, Garching, Germany
| | - Bernhard Rieger
- WACKER-Lehrstuhl für Makromolekulare Chemie, Technische Universität München, Lichtenbergstrasse 4, 85748, Garching, Germany.,Catalysis Research Center, Ernst-Otto-Fischer-Strasse 1, 85748, Garching, Germany
| | - Job Boekhoven
- Department of Chemistry, Technische Universität München, Lichtenbergstrasse 4, 85748, Garching, Germany.,Institute for Advanced Study, Technische Universität München, Lichtenbergstrasse 2a, 85748, Garching, Germany
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14
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Angı A, Loch M, Sinelnikov R, Veinot JGC, Becherer M, Lugli P, Rieger B. The influence of surface functionalization methods on the performance of silicon nanocrystal LEDs. NANOSCALE 2018; 10:10337-10342. [PMID: 29683161 DOI: 10.1039/c7nr09525b] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The influence of silicon nanocrystal (SiNC) surface characteristics obtained from different functionalization methods on the performance of LEDs was investigated. The surface of SiNCs was functionalized with hexyl chains via hydrosilylation (HS) or with organolithium reagents (OLR) and resulting SiNCs were incorporated as the emissive layer in hybrid organic/inorganic LEDs. Devices utilizing SiNCs functionalized with OLR consistently exhibited lower turn-on voltages, higher luminances and external quantum efficiencies compared to those obtained from the HS method. These improvements were attributed to the less dense and monolayer surface coverage of the SiNCs obtained by the OLR method, as well as their higher absolute quantum yield.
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Affiliation(s)
- Arzu Angı
- WACKER-Lehrstuhl für Makromolekulare Chemie, Technische Universität München, Lichtenbergstraße 4, 85747, Catalysis Research Center, Ernst-Otto-Fischer-Straße 1, 85748 Garching, Germany.
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15
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Sugimoto H, Yamamura M, Sakiyama M, Fujii M. Visualizing a core-shell structure of heavily doped silicon quantum dots by electron microscopy using an atomically thin support film. NANOSCALE 2018; 10:7357-7362. [PMID: 29637958 DOI: 10.1039/c7nr09474d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We successfully visualize a core-shell structure of a heavily B and P codoped Si quantum dot (QD) by transmission electron microscopy using an ultra-thin graphene oxide support film. The enhanced contrast reveals that a codoped Si QD has a highly crystalline Si core and an amorphous shell composed of Si, B and P.
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Affiliation(s)
- Hiroshi Sugimoto
- Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, Rokkodai, Nada, Kobe 657-8501, Japan.
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16
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Wu WS, Hao HL, Zhang YX, Li J, Wang JJ, Shen WZ. Correlation between luminescence and structural evolution of colloidal silicon nanocrystals synthesized under different laser fluences. NANOTECHNOLOGY 2018; 29:025709. [PMID: 29227969 DOI: 10.1088/1361-6528/aa95a1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present a detailed investigation of the structural evolution and photoluminescence (PL) properties of colloidal silicon (Si) nanocrystals (NCs) synthesized through femtosecond laser ablation at different laser fluences. It is shown that the mean size of colloidal Si NCs increases from ∼0.97-2.37 nm when increasing laser fluence from 1.0-2.5 mJ cm-2. On the basis of structural characterization, temperature-dependent PL, time-resolved PL, and PL excitation spectra, we identify that the size-dependent spectral shift of violet emission is attributed to the quantum confinement effect. The localized excitons' radiative recombination via the oxygen-related surface states on the surface of the colloidal Si NCs is employed to explain the origin of the blue emission.
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Affiliation(s)
- W S Wu
- College of Material Engineering, Shanghai University of Engineering Science, 333 Long Teng Road, Shanghai 201620, People's Republic of China
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17
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Ashkenazi O, Azulay D, Balberg I, Kano S, Sugimoto H, Fujii M, Millo O. Size-dependent donor and acceptor states in codoped Si nanocrystals studied by scanning tunneling spectroscopy. NANOSCALE 2017; 9:17884-17892. [PMID: 29120002 DOI: 10.1039/c7nr06257e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The electrical and optical properties of semiconductor nanocrystals (NCs) can be controlled, in addition to size and shape, by doping. However, such a process is not trivial in NCs due to the high formation energy of dopants there. Nevertheless, it has been shown theoretically that in the case of B and P (acceptor/donor) codoped Si-NCs the formation energy is reduced relative to that of single type doping. Previous comprehensive measurements on ensembles of such codoped Si-NCs have pointed to the presence of donor and acceptor states within the energy gap. However, such a conjecture has not been directly verified previously. Following that, we investigate here the electronic properties of B and P codoped Si-NCs via Scanning Tunneling Spectroscopy. We monitored the quantum confinement effect in this system, for which the energy gap changed from ∼1.4 eV to ∼1.8 eV with the decrease of NC diameter from 8.5 to 3.5 nm. Importantly, all spectra showed two in-gap band-states, one close to the conduction band edge and the other to the valence band edge, which we attribute to the P and B dopant levels, respectively. The energy separation between these dopants states decrease monotonically with increasing NC diameter, in parallel to the decrease of the conduction-to-valence bands separation. A fundamental quantity that is derived directly for these Si-NCs is the intrinsic like position of the Fermi energy, a non-trivial result that is very relevant for understanding the system. Following the above results we suggest an explanation for the character and the origin of the dopants bands.
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Affiliation(s)
- Or Ashkenazi
- Racah Institute of Physics and the Hebrew University Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
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18
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Kehrle J, Kaiser S, Purkait TK, Winnacker M, Helbich T, Vagin S, Veinot JGC, Rieger B. In situ IR-spectroscopy as a tool for monitoring the radical hydrosilylation process on silicon nanocrystal surfaces. NANOSCALE 2017; 9:8489-8495. [PMID: 28604898 DOI: 10.1039/c7nr02265d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Among a variety of SiNC functionalization methods, radical initiated grafting is very promising due to its straightforward nature and low propensity to form surface oligomers. In the present study, we employed in situ IR spectroscopy in combination with visible light transmittance measurements to investigate the radical induced grafting process on the well-defined SiNCs. Our findings support the proposed model: unfunctionalized hydride-terminated SiNCs form agglomerates in organic solvents, which break up during the grafting process. However, clearing of the dispersion is not a valid indicator for complete surface functionalization. Furthermore, radical-initiated grafting reactions in which azobisisobutyronitrile (AIBN) is the initiator are strongly influenced by external factors including initiator concentration, grafting temperature, as well as substrate steric demand. The monomer concentration was proven to have a low impact on the grafting process. Based on these new insights an underlying mechanism could be discussed, offering an unprecedented view on the functionalization of SiNC surfaces via radical initiated hydrosilylation.
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Affiliation(s)
- Julian Kehrle
- Catalysis Research Center/WACKER-Lehrstuhl für Makromolekulare Chemie, Technische Universität München, Lichtenbergstraße 4, 85747 Garching bei München, Germany.
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19
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Chen CL, Zeng J, Bao N, Dai H, Gu HY. Oxygen backed silicon hydride in correlation with the photoluminescence of silicon nano-crystals. RSC Adv 2017. [DOI: 10.1039/c7ra02883k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Converting silicon hydride (–SiH) to oxygen backed silicon hydride (–OSiH) on porous silicon leads to a shift in the wavelength of photoluminescence (PL) maximum from 670 to 605 nm, corresponding to an increase of 0.2 eV on emission energy.
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Affiliation(s)
- Cui-Li Chen
- College of Chemistry
- Chemical Engineering and Material Science
- Soochow University
- Suzhou
- China
| | - Jiang Zeng
- School of Public Health
- Nantong University
- Nantong
- China
| | - Ning Bao
- School of Public Health
- Nantong University
- Nantong
- China
| | - Hong Dai
- College of Chemistry and Chemical Engineering
- Nantong University
- Nantong 226019
- China
| | - Hai-Ying Gu
- College of Chemistry
- Chemical Engineering and Material Science
- Soochow University
- Suzhou
- China
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20
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Mazzaro R, Romano F, Ceroni P. Long-lived luminescence of silicon nanocrystals: from principles to applications. Phys Chem Chem Phys 2017; 19:26507-26526. [DOI: 10.1039/c7cp05208a] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Understanding parameters affecting the luminescence of silicon nanocrystals will guide the design of improved systems for a plethora of applications.
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Affiliation(s)
- Raffaello Mazzaro
- Department of Chemistry “Giacomo Ciamician”
- University of Bologna, and Interuniversity Center for the Chemical Conversion of Solar Energy (SolarChem)
- 40126 Bologna
- Italy
| | - Francesco Romano
- Department of Chemistry “Giacomo Ciamician”
- University of Bologna, and Interuniversity Center for the Chemical Conversion of Solar Energy (SolarChem)
- 40126 Bologna
- Italy
| | - Paola Ceroni
- Department of Chemistry “Giacomo Ciamician”
- University of Bologna, and Interuniversity Center for the Chemical Conversion of Solar Energy (SolarChem)
- 40126 Bologna
- Italy
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