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Yuan W, Chen B, Han ZK, You R, Jiang Y, Qi R, Li G, Wu H, Ganduglia-Pirovano MV, Wang Y. Direct in-situ insights into the asymmetric surface reconstruction of rutile TiO 2 (110). Nat Commun 2024; 15:1616. [PMID: 38388567 PMCID: PMC10883989 DOI: 10.1038/s41467-024-46011-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 02/09/2024] [Indexed: 02/24/2024] Open
Abstract
The reconstruction of rutile TiO2 (110) holds significant importance as it profoundly influences the surface chemistry and catalytic properties of this widely used material in various applications, from photocatalysis to solar energy conversion. Here, we directly observe the asymmetric surface reconstruction of rutile TiO2 (110)-(1×2) with atomic-resolution using in situ spherical aberration-corrected scanning transmission electron microscopy. Density functional theory calculations were employed to complement the experimental observations. Our findings highlight the pivotal role played by repulsive electrostatic interaction among the small polarons -formed by excess electrons following the removal of neutral oxygen atoms- and the subsequent surface relaxations induced by these polarons. The emergence and disappearance of these asymmetric structures can be controlled by adjusting the oxygen partial pressure. This research provides a deeper understanding, prediction, and manipulation of the surface reconstructions of rutile TiO2 (110), holding implications for a diverse range of applications and technological advancements involving rutile-based materials.
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Affiliation(s)
- Wentao Yuan
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
- Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering, 030000, Taiyuan, China
| | - Bingwei Chen
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Zhong-Kang Han
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China.
- Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195, Berlin, Germany.
| | - Ruiyang You
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Ying Jiang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Rui Qi
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Guanxing Li
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | - Hanglong Wu
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China
| | | | - Yong Wang
- Center of Electron Microscopy and State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, 310027, Hangzhou, China.
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Samarin SN, Petrov VN, Sudarshan K, Guagliardo P, Baraban AP, Williams JF. Positron re-emission, reflection, and diffraction from W(100) surface at very low energies. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 36:025001. [PMID: 37793396 DOI: 10.1088/1361-648x/ad0016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 10/04/2023] [Indexed: 10/06/2023]
Abstract
The energy distributions of scattered and re-emitted low-energy positrons from a W(100) surface were measured as a function of incident positron energy from 0 to 25 eV. Given that tungsten has a negative work function of about -3 eV for positrons, one can envisage three scenarios of very low-energy positron scattering from such a surface. First, a positron approaching the sample surface with energy say 1 eV above the vacuum level will see a potential barrier of about 2 eV height and will be reflected back to the vacuum. Second, when the energy of incident positrons increases up to the top of the surface potential barrier (positron work function), they start entering the solid and, therefore, the reflectivity of positrons from the surface reduces. Positrons entering the solid are thermalised within few picoseconds and have a chance to escape back to the vacuum with kinetic energy about 3 eV above the vacuum level undergoing so-calledre-emission. Third, coherent scattering of low-energy positrons may occur on the crystal surface, i.e. positron diffraction. All the three scenarios of low-energy positrons scattering are studied here experimentally. Measured spectra are very sensitive to the surface conditions of the sample: they change dramatically after surface oxidation or thin film deposition.
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Affiliation(s)
- S N Samarin
- Department of Physics, The University of Western Australia, Perth 6009, Australia
| | - V N Petrov
- Department of Physics, The University of Western Australia, Perth 6009, Australia
- St. Petersburg State Polytechnical University, St. Petersburg 195251, Russia
| | - K Sudarshan
- Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400085, India
| | - P Guagliardo
- Department of Physics, The University of Western Australia, Perth 6009, Australia
| | - A P Baraban
- St. Petersburg State University, St. Petersburg 198504, Russia
| | - J F Williams
- Department of Physics, The University of Western Australia, Perth 6009, Australia
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Dodenhöft M, Vohburger S, Hugenschmidt C. Total-reflection high-energy positron diffractometer at NEPOMUC - Instrumentation, simulation, and first measurements. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:115103. [PMID: 34852542 DOI: 10.1063/5.0062412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 10/11/2021] [Indexed: 06/13/2023]
Abstract
We report the instrumentation of a new positron diffractometer that is connected to the high-intensity positron beam at the neutron induced positron source Munich. Crucial elements for the adaption of the positron beam are presented, which include the magnetic field termination, the optional transmission-type remoderator for brightness enhancement, and the electrostatic system for acceleration and beam optics. The positron trajectories of the remoderated and the twofold remoderated beam have been simulated to optimize the system, i.e., to obtain a coherent beam of small diameter. Within a first beamtime, we tuned the system and characterized the direct beam. For the twofold remoderated beam of 10 keV energy, we experimentally observe a beam diameter of d < 1.3 mm, which agrees well with the simulation.
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Affiliation(s)
- Matthias Dodenhöft
- Technische Universität München and Forschungs-Neutronenquelle Heinz Maier-Leibnitz FRM II, Lichtenbergstr. 1, 85748 Garching, Germany
| | - Sebastian Vohburger
- Technische Universität München and Forschungs-Neutronenquelle Heinz Maier-Leibnitz FRM II, Lichtenbergstr. 1, 85748 Garching, Germany
| | - Christoph Hugenschmidt
- Technische Universität München and Forschungs-Neutronenquelle Heinz Maier-Leibnitz FRM II, Lichtenbergstr. 1, 85748 Garching, Germany
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Katsube D, Ojima S, Inami E, Abe M. Atomic-resolution imaging of rutile TiO 2(110)-(1 × 2) reconstructed surface by non-contact atomic force microscopy. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2020; 11:443-449. [PMID: 32215231 PMCID: PMC7082707 DOI: 10.3762/bjnano.11.35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/22/2020] [Indexed: 06/10/2023]
Abstract
The structure of the rutile TiO2(110)-(1 × 2) reconstructed surface is a phase induced by oxygen reduction. There is ongoing debate about the (1 × 2) reconstruction, because it cannot be clarified whether the (1 × 2) structure is formed over a wide area or only locally using macroscopic analysis methods such as diffraction. We used non-contact atomic force microscopy, scanning tunneling microscopy, and low-energy electron diffraction at room temperature to characterize the surface. Ti2O3 rows appeared as bright spots in both NC-AFM and STM images observed in the same area. High-resolution NC-AFM images revealed that the rutile TiO2(110)-(1 × 2) reconstructed surface is composed of two domains with different types of asymmetric rows.
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Affiliation(s)
- Daiki Katsube
- Graduate School of Engineering, Nagaoka University of Technology, 1603-1 Kamitomiokamachi, Nagaoka, Niigata 940-2188, Japan
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Shoki Ojima
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Eiichi Inami
- School of Systems Engineering, Kochi University of Technology, 185 Miyanokuchi, Tosayamada, Kami, Kochi 782-8502, Japan
| | - Masayuki Abe
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
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Kratzer M, Szajna K, Wrana D, Belza W, Krok F, Teichert C. Fabrication of ion bombardment induced rippled TiO 2 surfaces to influence subsequent organic thin film growth. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:283001. [PMID: 29790863 DOI: 10.1088/1361-648x/aac758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Control over organic thin film growth is a central issue in the development of organic electronics. The anisotropy and extended size of the molecular building blocks introduce a high degree of complexity within the formation of thin films. This complexity can be even increased for substrates with induced, sophisticated morphology and anisotropy. Thus, targeted structuring like ion beam mediated modification of substrates in order to create ripples, pyramids, or pit structures provides a further degree of freedom in manipulating the growth morphology of organic thin films. We provide a comprehensive review of recent work on para-hexaphenyl (C36H26, 6P) as a typical representative of the class of small, rod-like conjugated molecules and rutile TiO2(1 1 0) as an example for a transparent oxide electrode to demonstrate the effect of ion beam induced nanostructuring on organic thin film growth. Starting from molecular growth on smooth, atomically flat TiO2(1 1 0) (1 × 1) surfaces, we investigate the influence of the ripple size on the resulting 6P thin films. The achieved 6P morphologies are either crystalline nano-needles composed of flat lying molecules or islands consisting of upright standing 6P, which are elongated in ripple direction. The islands' length-to-width ratio can be controlled by tuning the ripples' shape.
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Affiliation(s)
- M Kratzer
- Montanuniversitaet Leoben, Franz Josef Straße 18, 8700 Leoben, Austria
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Merte LR, Jørgensen MS, Pussi K, Gustafson J, Shipilin M, Schaefer A, Zhang C, Rawle J, Nicklin C, Thornton G, Lindsay R, Hammer B, Lundgren E. Structure of the SnO_{2}(110)-(4×1) Surface. PHYSICAL REVIEW LETTERS 2017; 119:096102. [PMID: 28949575 DOI: 10.1103/physrevlett.119.096102] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Indexed: 05/08/2023]
Abstract
Using surface x-ray diffraction (SXRD), quantitative low-energy electron diffraction (LEED), and density-functional theory (DFT) calculations, we have determined the structure of the (4×1) reconstruction formed by sputtering and annealing of the SnO_{2}(110) surface. We find that the reconstruction consists of an ordered arrangement of Sn_{3}O_{3} clusters bound atop the bulk-terminated SnO_{2}(110) surface. The model was found by application of a DFT-based evolutionary algorithm with surface compositions based on SXRD, and shows excellent agreement with LEED and with previously published scanning tunneling microscopy measurements. The model proposed previously consisting of in-plane oxygen vacancies is thus shown to be incorrect, and our result suggests instead that Sn(II) species in interstitial positions are the more relevant features of reduced SnO_{2}(110) surfaces.
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Affiliation(s)
- Lindsay R Merte
- Division of Synchrotron Radiation Research, Lund University, 22 100 Lund, Sweden
| | - Mathias S Jørgensen
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Katariina Pussi
- LUT School of Engineering Science, P.O. Box 20, FIN-53851 Lappeenranta, Finland
| | - Johan Gustafson
- Division of Synchrotron Radiation Research, Lund University, 22 100 Lund, Sweden
| | - Mikhail Shipilin
- Division of Synchrotron Radiation Research, Lund University, 22 100 Lund, Sweden
| | - Andreas Schaefer
- Division of Synchrotron Radiation Research, Lund University, 22 100 Lund, Sweden
| | - Chu Zhang
- Division of Synchrotron Radiation Research, Lund University, 22 100 Lund, Sweden
| | - Jonathan Rawle
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Chris Nicklin
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, United Kingdom
| | - Geoff Thornton
- Department of Chemistry and London Centre for Nanotechnology, University College London, London WC1H 0AJ, United Kingdom
| | - Robert Lindsay
- Corrosion and Protection Centre, School of Materials, University of Manchester, Sackville Street, Manchester M13 9PL, United Kingdom
| | - Bjørk Hammer
- Interdisciplinary Nanoscience Center (iNANO) and Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Edvin Lundgren
- Division of Synchrotron Radiation Research, Lund University, 22 100 Lund, Sweden
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