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Edgecomb J, Nguyen DT, Tan S, Murugesan V, Johnson GE, Prabhakaran V. Electrochemical Imaging of Precisely-Defined Redox and Reactive Interfaces. Angew Chem Int Ed Engl 2024:e202405846. [PMID: 38871656 DOI: 10.1002/anie.202405846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Revised: 06/13/2024] [Accepted: 06/13/2024] [Indexed: 06/15/2024]
Abstract
Understanding the diverse electrochemical reactions occurring at electrode-electrolyte interfaces (EEIs) is a critical challenge to developing more efficient energy conversion and storage technologies. Establishing a predictive molecular-level understanding of solid electrolyte interphases (SEIs) is challenging due to the presence of multiple intertwined chemical and electrochemical processes occurring at battery electrodes. Similarly, chemical conversions in reactive electrochemical systems are often influenced by the heterogeneous distribution of active sites, surface defects, and catalyst particle sizes. In this mini review, we highlight an emerging field of interfacial science that isolates the impact of specific chemical species by preparing precisely-defined EEIs and visualizing the reactivity of their individual components using single-entity characterization techniques. We highlight the broad applicability and versatility of these methods, along with current state-of-the-art instrumentation and future opportunities for these approaches to address key scientific challenges related to batteries, chemical separations, and fuel cells. We establish that controlled preparation of well-defined electrodes combined with single entity characterization will be crucial to filling key knowledge gaps and advancing the theories used to describe and predict chemical and physical processes occurring at EEIs and accelerating new materials discovery for energy applications.
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Affiliation(s)
- Joseph Edgecomb
- Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | | | - Shuai Tan
- Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | | | - Grant E Johnson
- Pacific Northwest National Laboratory, Richland, WA 99352, USA
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2
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Das A, Samayoa-Oviedo HY, Mohapatra M, Basu S, Laskin J. Enhancing Energy Storage Capacity of 3D Carbon Electrodes Using Soft Landing of Molecular Redox Mediators. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2311585. [PMID: 38576110 DOI: 10.1002/smll.202311585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 03/08/2024] [Indexed: 04/06/2024]
Abstract
The incorporation of redox-active species into the electric double layer is a powerful strategy for enhancing the energy density of supercapacitors. Polyoxometalates (POM) are a class of stable, redox-active species with multielectron activity, which is often used to tailor the properties of electrochemical interfaces. Traditional synthetic methods often result in interfaces containing a mixture of POM anions, unreactive counter ions, and neutral species. This leads to degradation in electrochemical performance due to aggregation and increased interfacial resistance. Another significant challenge is achieving the uniform and stable anchoring of POM anions on substrates to ensure the long-term stability of the electrochemical interface. These challenges are addressed by developing a mass spectrometry-based subambient deposition strategy for the selective deposition of POM anions onto engineered 3D porous carbon electrodes. Furthermore, positively charged functional groups are introduced on the electrode surface for efficient trapping of POM anions. This approach enables the deposition of purified POM anions uniformly through the pores of the 3D porous carbon electrode, resulting in unprecedented increase in the energy storage capacity of the electrodes. The study highlights the critical role of well-defined electrochemical interfaces in energy storage applications and offers a powerful method to achieve this through selective ion deposition.
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Affiliation(s)
- Arya Das
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
- CSIR-Institute of Minerals and Materials Technology, Bhubaneswar, Odisha, 751013, India
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA
| | | | - Mamata Mohapatra
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
- CSIR-Institute of Minerals and Materials Technology, Bhubaneswar, Odisha, 751013, India
| | - Suddhasatwa Basu
- CSIR-Institute of Minerals and Materials Technology, Bhubaneswar, Odisha, 751013, India
| | - Julia Laskin
- Department of Chemistry, Purdue University, West Lafayette, IN, 47906, USA
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3
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Primera-Pedrozo OM, Tan S, Zhang D, O'Callahan BT, Cao W, Baxter ET, Wang XB, El-Khoury PZ, Prabhakaran V, Glezakou VA, Johnson GE. Influence of surface and intermolecular interactions on the properties of supported polyoxometalates. NANOSCALE 2023; 15:5786-5797. [PMID: 36857667 DOI: 10.1039/d2nr06148a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Polyoxometalates (POMs) with localized radical or open-shell metal sites have the potential to be used as transformative electronic spin based molecular qubits (MQs) for quantum computing (QC). For practical applications, MQs have to be immobilized in electronically or optically addressable arrays which introduces interactions with supports as well as neighboring POMs. Herein, we synthesized Keggin POMs with both tungsten (W) and vanadium (V) addenda atoms. Ion soft landing, a highly-controlled surface modification technique, was used to deliver mass-selected V-doped POMs to different self-assembled monolayer surfaces on gold (SAMs) without the solvent, counterions, and contaminants that normally accompany deposition from solution. Alkylthiol, perfluorinated, and carboxylic-acid terminated monolayers were employed as representative model supports on which different POM-surface and POM-POM interactions were characterized. We obtained insights into the vibrational properties of supported V-doped POMs and how they are perturbed by interactions with specific surface functional groups using infrared reflection absorption and scattering-type scanning near-field optical microscopy, as well as tip enhanced Raman spectroscopy. Different functional groups on SAMs and nanoscale heterogeneity are both shown to modulate the observed spectroscopic signatures. Spectral shifts are also found to be dependent on POM-POM interactions. The electronic structure of the V-doped POMs was determined in the gas phase using negative ion photoelectron spectroscopy and on surfaces with scanning Kelvin probe microscopy. The chemical functionality and charge transfer properties of the SAMs are demonstrated to exert an influence on the charge state and electronic configuration of supported V-doped POMs. The geometric and electronic structure of the POMs were also calculated using density functional theory. Our joint experimental and theoretical findings provide insight into how V substitution as well as POM-surface and POM-POM interactions influence the vibrational properties of POMs.
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Affiliation(s)
- Oliva M Primera-Pedrozo
- Pacific Northwest National Laboratory, Physical Sciences Division, P.O. Box 999, MSIN J7-10, Richland, Washington 99352, USA.
| | - Shuai Tan
- Pacific Northwest National Laboratory, Physical Sciences Division, P.O. Box 999, MSIN J7-10, Richland, Washington 99352, USA.
| | - Difan Zhang
- Pacific Northwest National Laboratory, Physical Sciences Division, P.O. Box 999, MSIN J7-10, Richland, Washington 99352, USA.
| | - Brian T O'Callahan
- Pacific Northwest National Laboratory, Earth and Biological Sciences Division, P.O. Box 999, MSIN K8-88, Richland, Washington 99352, USA
| | - Wenjin Cao
- Pacific Northwest National Laboratory, Physical Sciences Division, P.O. Box 999, MSIN J7-10, Richland, Washington 99352, USA.
| | - Eric T Baxter
- Pacific Northwest National Laboratory, Physical Sciences Division, P.O. Box 999, MSIN J7-10, Richland, Washington 99352, USA.
| | - Xue-Bin Wang
- Pacific Northwest National Laboratory, Physical Sciences Division, P.O. Box 999, MSIN J7-10, Richland, Washington 99352, USA.
| | - Patrick Z El-Khoury
- Pacific Northwest National Laboratory, Physical Sciences Division, P.O. Box 999, MSIN J7-10, Richland, Washington 99352, USA.
| | - Venkateshkumar Prabhakaran
- Pacific Northwest National Laboratory, Physical Sciences Division, P.O. Box 999, MSIN J7-10, Richland, Washington 99352, USA.
| | | | - Grant E Johnson
- Pacific Northwest National Laboratory, Physical Sciences Division, P.O. Box 999, MSIN J7-10, Richland, Washington 99352, USA.
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4
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Moors M, Warneke J, López X, de Graaf C, Abel B, Monakhov KY. Insights from Adsorption and Electron Modification Studies of Polyoxometalates on Surfaces for Molecular Memory Applications. Acc Chem Res 2021; 54:3377-3389. [PMID: 34427081 DOI: 10.1021/acs.accounts.1c00311] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This Account highlights recent experimental and theoretical work focusing on the development of polyoxometalates (POMs) as possible active switching units in what may be called "molecule-based memory cells". Herein, we critically discuss how multiply charged vanadium-containing POMs, which exhibit stable metal-oxo bonds and are characterized by the excellent ability to change their redox states without significant structural distortions of the central polyoxoanion core, can be immobilized best and how they may work optimally at appropriate surfaces. Furthermore, we critically discuss important issues and challenges on the long way toward POM-based nanoelectronics. This Account is divided into four sections shedding light on POM interplay in solution and on surfaces, ion soft-landing of mass-selected POMs on surfaces, electronic modification of POMs on surfaces, and computational modeling of POMs on surfaces. The sections showcase the complex nature of far-reaching POM interactions with the chemical surroundings in solution and the properties of POMs in the macroscopic environment of electrode surfaces. Section 2 describes complex relationships of POMs with their counter-cations, solvent molecules, and water impurities, which have been shown to exhibit a direct impact on the resulting surface morphology, where a concentration-dependent formation of micellar structures can be potentially observed. Section 3 gives insights into the ion soft-landing deposition of mass-selected POMs on electrode surfaces, which emerges as an appealing method because the simultaneous deposition of agglomeration-stimulating counter-cations can be avoided. Section 4 provides details of electronic properties of POMs and their modification by external electronic stimuli toward the development of multiple-state resistive (memristive) switches. Section 5 sheds light on issues of the determination of the electronic structure properties of POMs across their interfaces, which is difficult to address by experiment. The studies summarized in these four sections have employed various X-ray-scattering, microscopy, spectroscopy, and computational techniques for imaging of POM interfaces in solution and on surfaces to determine the adsorption type, agglomeration tendency, distribution, and oxidation state of deposited molecules. The presented research findings and conceptual ideas may assist experimentalists and theoreticians to advance the exploration of POM electrical conductivity as a function of metal redox and spin states and to pave the way for a realization of ("brain-inspired") POM-based memory devices, memristive POM-surface device engineering, and energy efficient nonvolatile data storage and processing technologies.
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Affiliation(s)
- Marco Moors
- Leibniz Institute of Surface Engineering (IOM), Permoserstraße 15, 04318 Leipzig, Germany
| | - Jonas Warneke
- Leibniz Institute of Surface Engineering (IOM), Permoserstraße 15, 04318 Leipzig, Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Leipzig University, Linnéstr. 2, 04103 Leipzig, Germany
| | - Xavier López
- Universitat Rovira i Virgili, Departament de Química Física i Inorgànica, c/Marcel·lí Domingo 1, 43007 Tarragona, Spain
| | - Coen de Graaf
- Universitat Rovira i Virgili, Departament de Química Física i Inorgànica, c/Marcel·lí Domingo 1, 43007 Tarragona, Spain
- ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain
| | - Bernd Abel
- Leibniz Institute of Surface Engineering (IOM), Permoserstraße 15, 04318 Leipzig, Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Leipzig University, Linnéstr. 2, 04103 Leipzig, Germany
| | - Kirill Yu. Monakhov
- Leibniz Institute of Surface Engineering (IOM), Permoserstraße 15, 04318 Leipzig, Germany
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5
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Su P, Hu H, Unsihuay D, Zhang D, Dainese T, Diaz RE, Lee J, Gunaratne DK, Wang H, Maran F, Mei J, Laskin J. Preparative Mass Spectrometry Using a Rotating‐Wall Mass Analyzer. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202000065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Pei Su
- Department of Chemistry Purdue University 560 Oval Drive West Lafayette IN 47907 USA
| | - Hang Hu
- Department of Chemistry Purdue University 560 Oval Drive West Lafayette IN 47907 USA
| | - Daisy Unsihuay
- Department of Chemistry Purdue University 560 Oval Drive West Lafayette IN 47907 USA
| | - Di Zhang
- School of Materials Engineering Purdue University 701 W. Stadium Avenue West Lafayette IN 47907 USA
| | - Tiziano Dainese
- Department of Chemistry University of Padova 1, Via Marzolo Padova 35131 Italy
| | - Rosa E. Diaz
- Birck Nanotechnology Center, Discovery Park Purdue University 1205 W. State St. West Lafayette IN 47907 USA
| | - Jongsu Lee
- Department of Chemistry Purdue University 560 Oval Drive West Lafayette IN 47907 USA
| | - Don K. Gunaratne
- Physical Science Division Pacific Northwest National Laboratory P.O. Box 999, MSIN K8-88 Richland WA 99352 USA
| | - Haiyan Wang
- School of Materials Engineering Purdue University 701 W. Stadium Avenue West Lafayette IN 47907 USA
- School of Electrical and Computer Engineering Purdue University 465 Northwestern Avenue West Lafayette IN 47907 USA
| | - Flavio Maran
- Department of Chemistry University of Padova 1, Via Marzolo Padova 35131 Italy
| | - Jianguo Mei
- Department of Chemistry Purdue University 560 Oval Drive West Lafayette IN 47907 USA
| | - Julia Laskin
- Department of Chemistry Purdue University 560 Oval Drive West Lafayette IN 47907 USA
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6
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Su P, Hu H, Unsihuay D, Zhang D, Dainese T, Diaz RE, Lee J, Gunaratne DK, Wang H, Maran F, Mei J, Laskin J. Preparative Mass Spectrometry Using a Rotating‐Wall Mass Analyzer. Angew Chem Int Ed Engl 2020; 59:7711-7716. [PMID: 32109333 DOI: 10.1002/anie.202000065] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 02/18/2020] [Indexed: 12/12/2022]
Affiliation(s)
- Pei Su
- Department of Chemistry Purdue University 560 Oval Drive West Lafayette IN 47907 USA
| | - Hang Hu
- Department of Chemistry Purdue University 560 Oval Drive West Lafayette IN 47907 USA
| | - Daisy Unsihuay
- Department of Chemistry Purdue University 560 Oval Drive West Lafayette IN 47907 USA
| | - Di Zhang
- School of Materials Engineering Purdue University 701 W. Stadium Avenue West Lafayette IN 47907 USA
| | - Tiziano Dainese
- Department of Chemistry University of Padova 1, Via Marzolo Padova 35131 Italy
| | - Rosa E. Diaz
- Birck Nanotechnology Center, Discovery Park Purdue University 1205 W. State St. West Lafayette IN 47907 USA
| | - Jongsu Lee
- Department of Chemistry Purdue University 560 Oval Drive West Lafayette IN 47907 USA
| | - Don K. Gunaratne
- Physical Science Division Pacific Northwest National Laboratory P.O. Box 999, MSIN K8-88 Richland WA 99352 USA
| | - Haiyan Wang
- School of Materials Engineering Purdue University 701 W. Stadium Avenue West Lafayette IN 47907 USA
- School of Electrical and Computer Engineering Purdue University 465 Northwestern Avenue West Lafayette IN 47907 USA
| | - Flavio Maran
- Department of Chemistry University of Padova 1, Via Marzolo Padova 35131 Italy
| | - Jianguo Mei
- Department of Chemistry Purdue University 560 Oval Drive West Lafayette IN 47907 USA
| | - Julia Laskin
- Department of Chemistry Purdue University 560 Oval Drive West Lafayette IN 47907 USA
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7
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Su P, Hu H, Warneke J, Belov ME, Anderson GA, Laskin J. Design and Performance of a Dual-Polarity Instrument for Ion Soft Landing. Anal Chem 2019; 91:5904-5912. [PMID: 30999743 DOI: 10.1021/acs.analchem.9b00309] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Pei Su
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Hang Hu
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Jonas Warneke
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnestr. 2, 04103 Leipzig, Germany
| | | | - Gordon A. Anderson
- GAA Custom Engineering, LLC, POB 335, Benton City, Washington 99320, United States
| | - Julia Laskin
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
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8
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Laskin J, Johnson GE, Warneke J, Prabhakaran V. Von isolierten Ionen zu mehrschichtigen funktionellen Materialien durch sanfte Landung von Ionen. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201712296] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Julia Laskin
- Department of Chemistry Purdue University West Lafayette IN 47907 USA
| | - Grant E. Johnson
- Physical Sciences Division Pacific Northwest National Laboratory Richland WA 99352 USA
| | - Jonas Warneke
- Physical Sciences Division Pacific Northwest National Laboratory Richland WA 99352 USA
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9
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Laskin J, Johnson GE, Warneke J, Prabhakaran V. From Isolated Ions to Multilayer Functional Materials Using Ion Soft Landing. Angew Chem Int Ed Engl 2018; 57:16270-16284. [DOI: 10.1002/anie.201712296] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Julia Laskin
- Department of Chemistry Purdue University West Lafayette IN 47907 USA
| | - Grant E. Johnson
- Physical Sciences Division Pacific Northwest National Laboratory Richland WA 99352 USA
| | - Jonas Warneke
- Physical Sciences Division Pacific Northwest National Laboratory Richland WA 99352 USA
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10
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Su P, Prabhakaran V, Johnson GE, Laskin J. In Situ Infrared Spectroelectrochemistry for Understanding Structural Transformations of Precisely Defined Ions at Electrochemical Interfaces. Anal Chem 2018; 90:10935-10942. [DOI: 10.1021/acs.analchem.8b02440] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Pei Su
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | | | - Grant E. Johnson
- Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
| | - Julia Laskin
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
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11
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Warneke J, McBriarty ME, Riechers SL, China S, Engelhard MH, Aprà E, Young RP, Washton NM, Jenne C, Johnson GE, Laskin J. Self-organizing layers from complex molecular anions. Nat Commun 2018; 9:1889. [PMID: 29760476 PMCID: PMC5951818 DOI: 10.1038/s41467-018-04228-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 04/10/2018] [Indexed: 11/17/2022] Open
Abstract
The formation of traditional ionic materials occurs principally via joint accumulation of both anions and cations. Herein, we describe a previously unreported phenomenon by which macroscopic liquid-like thin layers with tunable self-organization properties form through accumulation of stable complex ions of one polarity on surfaces. Using a series of highly stable molecular anions we demonstrate a strong influence of the internal charge distribution of the molecular ions, which is usually shielded by counterions, on the properties of the layers. Detailed characterization reveals that the intrinsically unstable layers of anions on surfaces are stabilized by simultaneous accumulation of neutral molecules from the background environment. Different phases, self-organization mechanisms and optical properties are observed depending on the molecular properties of the deposited anions, the underlying surface and the coadsorbed neutral molecules. This demonstrates rational control of the macroscopic properties (morphology and size of the formed structures) of the newly discovered anion-based layers.
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Affiliation(s)
- Jonas Warneke
- Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN K8-88, Richland, WA, 99352, USA.
| | - Martin E McBriarty
- Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN K8-88, Richland, WA, 99352, USA
| | - Shawn L Riechers
- Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN K8-88, Richland, WA, 99352, USA
| | - Swarup China
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA, 99352, USA
| | - Mark H Engelhard
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA, 99352, USA
| | - Edoardo Aprà
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA, 99352, USA
| | - Robert P Young
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA, 99352, USA
| | - Nancy M Washton
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, P.O. Box 999, Richland, WA, 99352, USA
| | - Carsten Jenne
- Fakultät für Mathematik und Naturwissenschaften, Anorganische Chemie, Bergische Universität Wuppertal, Gaußstraße 20, Wuppertal, 42119, Germany
| | - Grant E Johnson
- Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN K8-88, Richland, WA, 99352, USA
| | - Julia Laskin
- Physical Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, MSIN K8-88, Richland, WA, 99352, USA.
- Department of Chemistry, Purdue University, West Lafayette, IN, 47907, USA.
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12
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Vats N, Rauschenbach S, Sigle W, Sen S, Abb S, Portz A, Dürr M, Burghard M, van Aken PA, Kern K. Electron microscopy of polyoxometalate ions on graphene by electrospray ion beam deposition. NANOSCALE 2018; 10:4952-4961. [PMID: 29485651 DOI: 10.1039/c8nr00402a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Aberration-corrected high-resolution transmission electron microscopy (AC-HRTEM) has enabled atomically resolved imaging of molecules adsorbed on low-dimensional materials like carbon nanotubes, graphene oxide and few-layer-graphene. However, conventional methods for depositing molecules onto such supports lack selectivity and specificity. Here, we describe the chemically selective preparation and deposition of molecules-like polyoxometalate (POM) anions [PW12O40]3- using electrospray ion-beam deposition (ES-IBD) along with high-resolution TEM imaging. This approach provides access to sub-monolayer coatings of intact molecules on freestanding graphene, which enables their atomically resolved ex situ characterization by low-voltage AC-HRTEM. The capability to tune the deposition parameters in either soft or reactive landing mode, combined with the well-defined high-vacuum deposition conditions, renders the ES-IBD based method advantageous over alternative methods such as drop-casting. Furthermore, it might be expanded towards depositing and imaging large and nonvolatile molecules with complex structures.
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Affiliation(s)
- N Vats
- Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
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