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Yang C, Yang C, Guo Y, Feng J, Guo X. Graphene-molecule-graphene single-molecule junctions to detect electronic reactions at the molecular scale. Nat Protoc 2023:10.1038/s41596-023-00822-x. [PMID: 37045993 DOI: 10.1038/s41596-023-00822-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 02/09/2023] [Indexed: 04/14/2023]
Abstract
The ability to measure the behavior of a single molecule during a reaction implies the detection of inherent dynamic and static disordered states, which may not be represented when measuring ensemble averages. Here, we describe the building of devices with graphene-molecule-graphene single-molecule junctions integrated into an electrical circuit. These devices are simple to build and are stable, showing tolerance to mechanical changes, solution environment and voltage stimulation. The design of a conductive channel based on a single molecule enables single-molecule detection and is sensitive to variations in physical properties and chemical structures of the detected molecules. The on-chip setup of single-molecule junctions further offers complementary metal-oxide-semiconductor (CMOS) compatibility, enabling logic functions in circuit elements, as well as deciphering of reaction intermediates. We detail the experimental procedure to prepare graphene transistor arrays as a basis for single-molecule junctions and the preparation of nanogapped carboxyl-terminal graphene electrodes by using electron-beam lithography and oxygen plasma etching. We describe the basic design of a molecular bridge with desired functions and terminals to form covalent bonds with electrode arrays, via a chemical reaction, to construct stably integrated single-molecule devices with a yield of 30-50% per chip. The immobilization of the single molecules is then characterized by using inelastic electron tunneling spectra, single-molecule imaging and fluorescent spectra. The whole protocol can be implemented within 2 weeks and requires users trained in using ultra-clean laboratory facilities and the aforementioned instrumentation.
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Affiliation(s)
- Chen Yang
- Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Centre, College of Chemistry and Molecular Engineering, Peking University, Beijing, People's Republic of China
| | - Caiyao Yang
- Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Centre, College of Chemistry and Molecular Engineering, Peking University, Beijing, People's Republic of China
| | - Yilin Guo
- Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Centre, College of Chemistry and Molecular Engineering, Peking University, Beijing, People's Republic of China
| | - Jianfei Feng
- Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Centre, College of Chemistry and Molecular Engineering, Peking University, Beijing, People's Republic of China
| | - Xuefeng Guo
- Beijing National Laboratory for Molecular Sciences, National Biomedical Imaging Centre, College of Chemistry and Molecular Engineering, Peking University, Beijing, People's Republic of China.
- Centre of Single-Molecule Sciences, Institute of Modern Optics, Frontiers Science Centre for New Organic Matter, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, College of Electronic Information and Optical Engineering, Nankai University, Tianjin, People's Republic of China.
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Martín-Pérez L, Medina Rivero S, Vázquez Sulleiro M, Naranjo A, Gómez IJ, Ruíz-González ML, Castellanos-Gomez A, Garcia-Hernandez M, Pérez EM, Burzurí E. Direct Magnetic Evidence, Functionalization, and Low-Temperature Magneto-Electron Transport in Liquid-Phase Exfoliated FePS 3. ACS NANO 2023; 17:3007-3018. [PMID: 36651757 PMCID: PMC9933618 DOI: 10.1021/acsnano.2c11654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 01/05/2023] [Indexed: 06/17/2023]
Abstract
Magnetism and the existence of magnetic order in a material is determined by its dimensionality. In this regard, the recent emergence of magnetic layered van der Waals (vdW) materials provides a wide playground to explore the exotic magnetism arising in the two-dimensional (2D) limit. The magnetism of 2D flakes, especially antiferromagnetic ones, however, cannot be easily probed by conventional magnetometry techniques, being often replaced by indirect methods like Raman spectroscopy. Here, we make use of an alternative approach to provide direct magnetic evidence of few-layer vdW materials, including antiferromagnets. We take advantage of a surfactant-free, liquid-phase exfoliation (LPE) method to obtain thousands of few-layer FePS3 flakes that can be quenched in a solvent and measured in a conventional SQUID magnetometer. We show a direct magnetic evidence of the antiferromagnetic transition in FePS3 few-layer flakes, concomitant with a clear reduction of the Néel temperature with the flake thickness, in contrast with previous Raman reports. The quality of the LPE FePS3 flakes allows the study of electron transport down to cryogenic temperatures. The significant through-flake conductance is sensitive to the antiferromagnetic order transition. Besides, an additional rich spectra of electron transport excitations, including secondary magnetic transitions and potentially magnon-phonon hybrid states, appear at low temperatures. Finally, we show that the LPE is additionally a good starting point for the mass covalent functionalization of 2D magnetic materials with functional molecules. This technique is extensible to any vdW magnetic family.
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Affiliation(s)
- Lucía Martín-Pérez
- IMDEA
Nanociencia C/Faraday 9, Ciudad Universitaria
de Cantoblanco, 28049 Madrid, Spain
| | - Samara Medina Rivero
- IMDEA
Nanociencia C/Faraday 9, Ciudad Universitaria
de Cantoblanco, 28049 Madrid, Spain
| | | | - Alicia Naranjo
- IMDEA
Nanociencia C/Faraday 9, Ciudad Universitaria
de Cantoblanco, 28049 Madrid, Spain
| | - I. Jénnifer Gómez
- Department
of Condensed Matter Physics, Faculty of Science, Masaryk University, Kotlářská 2, 61137 Brno, Czech Republic
| | | | - Andres Castellanos-Gomez
- 2D
Foundry, Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas
(CSIC), 28049 Madrid, Spain
| | - Mar Garcia-Hernandez
- 2D
Foundry, Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas
(CSIC), 28049 Madrid, Spain
| | - Emilio M. Pérez
- IMDEA
Nanociencia C/Faraday 9, Ciudad Universitaria
de Cantoblanco, 28049 Madrid, Spain
| | - Enrique Burzurí
- IMDEA
Nanociencia C/Faraday 9, Ciudad Universitaria
de Cantoblanco, 28049 Madrid, Spain
- Departamento
de Física de la Materia Condensada and Condensed Matter Physics
Center (IFIMAC), Universidad Autónoma
de Madrid, 28049 Madrid, Spain
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Martín-Pérez L, Burzurí E. Optimized Liquid-Phase Exfoliation of Magnetic van der Waals Heterostructures: Towards the Single Layer and Deterministic Fabrication of Devices. Molecules 2021; 26:molecules26237371. [PMID: 34885953 PMCID: PMC8658876 DOI: 10.3390/molecules26237371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 11/23/2021] [Accepted: 12/02/2021] [Indexed: 11/22/2022] Open
Abstract
Van der Waals magnetic materials are promising candidates for spintronics and testbeds for exotic magnetic phenomena in low dimensions. The two-dimensional (2D) limit in these materials is typically reached by mechanically breaking the van der Waals interactions between layers. Alternative approaches to producing large amounts of flakes rely on wet methods such as liquid-phase exfoliation (LPE). Here, we report an optimized route for obtaining monolayers of magnetic cylindrite by LPE. We show that the selection of exfoliation times is the determining factor in producing a statistically significant amount of monolayers while keeping relatively big flake areas (~1 µm2). We show that the cylindrite lattice is preserved in the flakes after LPE. To study the electron transport properties, we have fabricated field-effect transistors based on LPE cylindrite. Flakes are deterministically positioned between nanoscale electrodes by dielectrophoresis. We show that dielectrophoresis can selectively move the larger flakes into the devices. Cylindrite nanoscale flakes present a p-doped semiconducting behaviour, in agreement with the mechanically exfoliated counterparts. Alternating current (AC) admittance spectroscopy sheds light on the role played by potential barriers between different flakes in terms of electron transport properties. The present large-scale exfoliation and device fabrication strategy can be extrapolated to other families of magnetic materials.
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Affiliation(s)
- Lucía Martín-Pérez
- IMDEA Nanociencia, Campus de Cantoblanco, Calle Faraday 9, 28049 Madrid, Spain;
| | - Enrique Burzurí
- IMDEA Nanociencia, Campus de Cantoblanco, Calle Faraday 9, 28049 Madrid, Spain;
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain
- Correspondence:
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Varodi C, Pogăcean F, Coros M, Magerusan L, Stefan-van Staden RI, Pruneanu S. Hydrothermal Synthesis of Nitrogen, Boron Co-Doped Graphene with Enhanced Electro-Catalytic Activity for Cymoxanil Detection. SENSORS (BASEL, SWITZERLAND) 2021; 21:6630. [PMID: 34640950 PMCID: PMC8512315 DOI: 10.3390/s21196630] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 09/29/2021] [Accepted: 09/30/2021] [Indexed: 02/06/2023]
Abstract
A sample of nitrogen and boron co-doped graphene (NB-Gr) was obtained by the hydrothermal method using urea and boric acid as doping sources. According to XRD analysis, the NB-Gr sample was formed by five-layer graphene. In addition, the XPS analysis confirmed the nitrogen and boron co-doping of the graphene sample. After synthesis, the investigation of the electro-catalytic properties of the bare (GC) and graphene-modified electrode (NB-Gr/GC) towards cymoxanil detection (CYM) was performed. Significant differences between the two electrodes were noticed. In the first case (GC) the peak current modulus was small (1.12 × 10-5 A) and appeared in the region of negative potentials (-0.9 V). In contrast, when NB-Gr was present on top of the GC electrode it promoted the transfer of electrons, leading to a large peak current increase (1.65 × 10-5 A) and a positive shift of the peak potential (-0.75 V). The NB-Gr/GC electrode was also tested for its ability to detect cymoxanil from a commercial fungicide (CURZATE MANOX) by the standard addition method, giving a recovery of 99%.
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Affiliation(s)
- Codruța Varodi
- National Institute for Research and Development of Isotopic and Molecular Technologies, Donat Street No. 67-103, 400293 Cluj-Napoca, Romania; (C.V.); (F.P.); (L.M.)
| | - Florina Pogăcean
- National Institute for Research and Development of Isotopic and Molecular Technologies, Donat Street No. 67-103, 400293 Cluj-Napoca, Romania; (C.V.); (F.P.); (L.M.)
| | - Maria Coros
- National Institute for Research and Development of Isotopic and Molecular Technologies, Donat Street No. 67-103, 400293 Cluj-Napoca, Romania; (C.V.); (F.P.); (L.M.)
| | - Lidia Magerusan
- National Institute for Research and Development of Isotopic and Molecular Technologies, Donat Street No. 67-103, 400293 Cluj-Napoca, Romania; (C.V.); (F.P.); (L.M.)
| | - Raluca-Ioana Stefan-van Staden
- Laboratory of Electrochemistry and PATLAB, National Institute of Research for Electrochemistry and Condensed Matter, 060021 Bucharest, Romania;
- Faculty of Applied Chemistry and Material Science, University Politehnica of Bucharest, 060021 Bucharest, Romania
| | - Stela Pruneanu
- National Institute for Research and Development of Isotopic and Molecular Technologies, Donat Street No. 67-103, 400293 Cluj-Napoca, Romania; (C.V.); (F.P.); (L.M.)
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