1
|
de Oteyza DG, Frederiksen T. Carbon-based nanostructures as a versatile platform for tunable π-magnetism. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:443001. [PMID: 35977474 DOI: 10.1088/1361-648x/ac8a7f] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 08/17/2022] [Indexed: 06/15/2023]
Abstract
Emergence ofπ-magnetism in open-shell nanographenes has been theoretically predicted decades ago but their experimental characterization was elusive due to the strong chemical reactivity that makes their synthesis and stabilization difficult. In recent years, on-surface synthesis under vacuum conditions has provided unprecedented opportunities for atomically precise engineering of nanographenes, which in combination with scanning probe techniques have led to a substantial progress in our capabilities to realize localized electron spin states and to control electron spin interactions at the atomic scale. Here we review the essential concepts and the remarkable advances in the last few years, and outline the versatility of carbon-basedπ-magnetic materials as an interesting platform for applications in spintronics and quantum technologies.
Collapse
Affiliation(s)
- Dimas G de Oteyza
- Nanomaterials and Nanotechnology Research Center (CINN), CSIC-UNIOVI-PA, E-33940 El Entrego, Spain
- Donostia International Physics Center (DIPC)-UPV/EHU, E-20018 San Sebastián, Spain
| | - Thomas Frederiksen
- Donostia International Physics Center (DIPC)-UPV/EHU, E-20018 San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, E-48013 Bilbao, Spain
| |
Collapse
|
2
|
Band Structure and Energy Level Alignment of Chiral Graphene Nanoribbons on Silver Surfaces. NANOMATERIALS 2021; 11:nano11123303. [PMID: 34947652 PMCID: PMC8705322 DOI: 10.3390/nano11123303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 11/29/2021] [Accepted: 12/02/2021] [Indexed: 01/29/2023]
Abstract
Chiral graphene nanoribbons are extremely interesting structures due to their narrow band gaps and potential development of spin-polarized edge states. Here, we study their band structure on low work function silver surfaces. The use of a curved Ag single crystal provides, within the same sample, regions of disparate step structure and step density. Whereas the former leads to distinct azimuthal growth orientations of the graphene nanoribbons atop, the latter modulates the substrate's work function and thereby the interface energy level alignment. In turn, we disclose the associated charge transfer from the substrate to the ribbon and assess its effect on the nanoribbon's properties and the edge state magnetization.
Collapse
|
3
|
Moca CP, Izumida W, Dóra B, Legeza Ö, Asbóth JK, Zaránd G. Topologically Protected Correlated End Spin Formation in Carbon Nanotubes. PHYSICAL REVIEW LETTERS 2020; 125:056401. [PMID: 32794861 DOI: 10.1103/physrevlett.125.056401] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 06/04/2020] [Indexed: 06/11/2023]
Abstract
For most chiralities, semiconducting nanotubes display topologically protected end states of multiple degeneracies. We demonstrate using density matrix renormalization group based quantum chemistry tools that the presence of Coulomb interactions induces the formation of robust end spins. These are the close analogs of ferromagnetic edge states emerging in graphene nanoribbons. The interaction between the two ends is sensitive to the length of the nanotube, its dielectric constant, and the size of the end spins: for S=1/2 end spins, their interaction is antiferromagnetic, while for S>1/2, it changes from antiferromagnetic to ferromagnetic as the nanotube length increases. The interaction between end spins can be controlled by changing the dielectric constant of the environment, thereby providing a possible platform for two-spin quantum manipulations.
Collapse
Affiliation(s)
- Cătălin Paşcu Moca
- MTA-BME Quantum Dynamics and Correlations Research Group, Institute of Physics, Budapest University of Technology and Economics, Budafoki út 8., H-1111 Budapest, Hungary
- Department of Physics, University of Oradea, 410087 Oradea, Romania
| | - Wataru Izumida
- Department of Physics, Tohoku University, Sendai 980-8578, Japan
| | - Balázs Dóra
- Department of Theoretical Physics and MTA-BME Lendület Topology and Correlation Research Group, Budapest University of Technology and Economics, 1521 Budapest, Hungary
| | - Örs Legeza
- Strongly Correlated Systems Lendület Research Group, Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest, Hungary
| | - János K Asbóth
- MTA-BME Quantum Dynamics and Correlations Research Group, Institute of Physics, Budapest University of Technology and Economics, Budafoki út 8., H-1111 Budapest, Hungary
- BME-MTA Exotic Quantum Phases Lendület Research Group, Institute of Physics, Budapest University of Technology and Economics, Budafoki út 8., H-1111 Budapest, Hungary
| | - Gergely Zaránd
- MTA-BME Quantum Dynamics and Correlations Research Group, Institute of Physics, Budapest University of Technology and Economics, Budafoki út 8., H-1111 Budapest, Hungary
- BME-MTA Exotic Quantum Phases Lendület Research Group, Institute of Physics, Budapest University of Technology and Economics, Budafoki út 8., H-1111 Budapest, Hungary
| |
Collapse
|
4
|
Zhao X, Yao C, Liu T, Hamill JC, Ngongang Ndjawa GO, Cheng G, Yao N, Meng H, Loo YL. Extending the Photovoltaic Response of Perovskite Solar Cells into the Near-Infrared with a Narrow-Bandgap Organic Semiconductor. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1904494. [PMID: 31523862 DOI: 10.1002/adma.201904494] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 08/17/2019] [Indexed: 06/10/2023]
Abstract
Typical lead-based perovskites solar cells show an onset of photogeneration around 800 nm, leaving plenty of spectral loss in the near-infrared (NIR). Extending light absorption beyond 800 nm into the NIR should increase photocurrent generation and further improve photovoltaic efficiency of perovskite solar cells (PSCs). Here, a simple and facile approach is reported to incorporate a NIR-chromophore that is also a Lewis-base into perovskite absorbers to broaden their photoresponse and increase their photovoltaic efficiency. Compared with pristine PSCs without such an organic chromophore, these solar cells generate photocurrent in the NIR beyond the band edge of the perovskite active layer alone. Given the Lewis-basic nature of the organic semiconductor, its addition to the photoactive layer also effectively passivates perovskite defects. These films thus exhibit significantly reduced trap densities, enhanced hole and electron mobilities, and suppressed illumination-induced ion migration. As a consequence, perovskite solar cells with organic chromophore exhibit an enhanced efficiency of 21.6%, and substantively improved operational stability under continuous one-sun illumination. The results demonstrate the potential generalizability of directly incorporating a multifunctional organic semiconductor that both extends light absorption and passivates surface traps in perovskite active layers to yield highly efficient and stable NIR-harvesting PSCs.
Collapse
Affiliation(s)
- Xiaoming Zhao
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Chao Yao
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA
- School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Tianran Liu
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - J Clay Hamill
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA
| | | | - Guangming Cheng
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, 08544, USA
| | - Nan Yao
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, 08544, USA
| | - Hong Meng
- School of Advanced Materials, Peking University Shenzhen Graduate School, Shenzhen, 518055, China
| | - Yueh-Lin Loo
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, 08544, USA
| |
Collapse
|
5
|
Tuček J, Błoński P, Ugolotti J, Swain AK, Enoki T, Zbořil R. Emerging chemical strategies for imprinting magnetism in graphene and related 2D materials for spintronic and biomedical applications. Chem Soc Rev 2018; 47:3899-3990. [PMID: 29578212 DOI: 10.1039/c7cs00288b] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Graphene, a single two-dimensional sheet of carbon atoms with an arrangement mimicking the honeycomb hexagonal architecture, has captured immense interest of the scientific community since its isolation in 2004. Besides its extraordinarily high electrical conductivity and surface area, graphene shows a long spin lifetime and limited hyperfine interactions, which favors its potential exploitation in spintronic and biomedical applications, provided it can be made magnetic. However, pristine graphene is diamagnetic in nature due to solely sp2 hybridization. Thus, various attempts have been proposed to imprint magnetic features into graphene. The present review focuses on a systematic classification and physicochemical description of approaches leading to equip graphene with magnetic properties. These include introduction of point and line defects into graphene lattices, spatial confinement and edge engineering, doping of graphene lattice with foreign atoms, and sp3 functionalization. Each magnetism-imprinting strategy is discussed in detail including identification of roles of various internal and external parameters in the induced magnetic regimes, with assessment of their robustness. Moreover, emergence of magnetism in graphene analogues and related 2D materials such as transition metal dichalcogenides, metal halides, metal dinitrides, MXenes, hexagonal boron nitride, and other organic compounds is also reviewed. Since the magnetic features of graphene can be readily masked by the presence of magnetic residues from synthesis itself or sample handling, the issue of magnetic impurities and correct data interpretations is also addressed. Finally, current problems and challenges in magnetism of graphene and related 2D materials and future potential applications are also highlighted.
Collapse
Affiliation(s)
- Jiří Tuček
- Regional Centre of Advanced Technologies and Materials, Department of Physical Chemistry, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71 Olomouc, Czech Republic.
| | | | | | | | | | | |
Collapse
|
6
|
Maji R, Bhattacharjee J. Bias induced ferromagnetism and half-metallicity in graphene nano-ribbons. Sci Rep 2017; 7:17094. [PMID: 29213098 PMCID: PMC5719007 DOI: 10.1038/s41598-017-17091-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 11/20/2017] [Indexed: 11/09/2022] Open
Abstract
Towards spin selective electronics made of three coordinated carbon atoms, here we computationally propose robust and reversibly bias driven evolution of pristine undoped graphene nano-ribbons(GNR) into ferromagnetic-semiconductor, metal or a half metal, irrespective of their edge configurations. The evolution is a result of a rare ferromagnetic(FM) order emerging among nearest neighbouring(n-n) sites, in positively biased regions in their in-homogeneous bias unit-cells, in attempt to cooperatively minimise on-site Coulomb repulsion and kinetic energy, while maximising localization of electrons at the positively biased sites. The phenomenon appears to be a general property of in-homogeneously biased Coulomb correlated bipartite systems. Consequences are particularly rich in zigzag edged graphene nano-ribbons(ZGNR) due to the contest of bias driven n-n FM order and the inter-edge antiferromagnetic order inherent to ZGNRs, leading to systematic closing of gap for one of the spins, amounting to bias controlled unmissable opening of window for FM-semiconducting and half-metallic transport.
Collapse
Affiliation(s)
- Rita Maji
- School of Physical Sciences, National Institute of Science Education and Research, Homi Bhava National Institute, Jatani, P.O, Khurda, Odisha, 752050, India
| | - Joydeep Bhattacharjee
- School of Physical Sciences, National Institute of Science Education and Research, Homi Bhava National Institute, Jatani, P.O, Khurda, Odisha, 752050, India.
| |
Collapse
|
7
|
Matsuoka W, Ito H, Itami K. Rapid Access to Nanographenes and Fused Heteroaromatics by Palladium-Catalyzed Annulative π-Extension Reaction of Unfunctionalized Aromatics with Diiodobiaryls. Angew Chem Int Ed Engl 2017; 56:12224-12228. [PMID: 28800388 DOI: 10.1002/anie.201707486] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Indexed: 01/23/2023]
Abstract
Efficient and rapid access to nanographenes and π-extended fused heteroaromatics is important in materials science. Herein, we report a palladium-catalyzed efficient one-step annulative π-extension (APEX) reaction of polycyclic aromatic hydrocarbons (PAHs) and heteroaromatics, producing various π-extended aromatics. In the presence of a cationic Pd complex, triflic acid, silver pivalate, and diiodobiaryls, diverse unfunctionalized PAHs and heteroaromatics were directly transformed into larger PAHs, nanographenes, and π-extended fused heteroaromatics in a single step. In the reactions that afford [5]helicene substructures, simultaneous dehydrogenative ring closures occur at the fjord regions to form unprecedented larger nanographenes. This successive APEX reaction is notable as it stiches five aryl-aryl bonds by C-H functionalization in a single operation. Moreover, the unique molecular structures, crystal-packing structures, photophysical properties, and frontier molecular orbitals of the thus-formed nanographenes were elucidated.
Collapse
Affiliation(s)
- Wataru Matsuoka
- Graduate School of Science, Nagoya University, Chikusa, Nagoya, 464-8602, Japan
| | - Hideto Ito
- Graduate School of Science, Nagoya University, Chikusa, Nagoya, 464-8602, Japan
| | - Kenichiro Itami
- Graduate School of Science, Nagoya University, Chikusa, Nagoya, 464-8602, Japan.,Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya, 464-8601, Japan.,JST-ERATO, Itami Molecular Nanocarbon Project, Nagoya University, Chikusa, Nagoya, 464-8602, Japan
| |
Collapse
|
8
|
Matsuoka W, Ito H, Itami K. Rapid Access to Nanographenes and Fused Heteroaromatics by Palladium‐Catalyzed Annulative π‐Extension Reaction of Unfunctionalized Aromatics with Diiodobiaryls. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201707486] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Wataru Matsuoka
- Graduate School of Science Nagoya University Chikusa Nagoya 464-8602 Japan
| | - Hideto Ito
- Graduate School of Science Nagoya University Chikusa Nagoya 464-8602 Japan
| | - Kenichiro Itami
- Graduate School of Science Nagoya University Chikusa Nagoya 464-8602 Japan
- Institute of Transformative Bio-Molecules (WPI-ITbM) Nagoya University Chikusa Nagoya 464-8601 Japan
- JST-ERATO Itami Molecular Nanocarbon Project Nagoya University Chikusa Nagoya 464-8602 Japan
| |
Collapse
|
9
|
Hayashi H, Aratani N, Yamada H. Semiconducting Self-Assembled Nanofibers Prepared from Photostable Octafluorinated Bisanthene Derivatives. Chemistry 2017; 23:7000-7008. [PMID: 28256784 DOI: 10.1002/chem.201700080] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2017] [Indexed: 11/07/2022]
Abstract
Bisanthene is an important class of small two-dimensional polycyclic aromatic hydrocarbons with a zigzag-edged graphene nanoribbon character. Therefore, the functionalization and deep understanding of the structure-property relationship of bisanthene would provide an effective design for small organic molecular devices. In this study, octa- and tetrafluorinated bisanthene derivatives were synthesized for investigating the effect of electronegative fluorine substitution on the structure and physical property of bisanthene. Firstly, the octafluorinated bisanthene derivative has a twisted structure due to the steric repulsion of fluorine atoms at the bay region. Secondly, the absorption and fluorescence peak maxima are blueshifted with an increase in the degree of fluorine substitution. Notably, a triisopropylsilylethynyl-substituted octafluorinated derivative (F8) exhibited strong fluorescence at 657 nm with high fluorescence quantum yield (84 %). Additionally, cyclic voltammograms indicate the positive effect of fluorine substitution on the high highest occupied molecular orbital energy level of the molecules; thus, F8 molecule exhibited a remarkably increased photostability. Finally, the self-assembled behavior of fluorinated compounds was investigated by scanning electron microscopy and X-ray diffraction analysis. Specifically, F8 self-assembled to form bundles of long semicrystalline nanofibers exhibiting hole-transporting properties (3.4×10-3 cm2 V-1 s-1 ).
Collapse
Affiliation(s)
- Hironobu Hayashi
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, 630-0192, Japan
| | - Naoki Aratani
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, 630-0192, Japan
| | - Hiroko Yamada
- Graduate School of Materials Science, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, 630-0192, Japan
| |
Collapse
|
10
|
Edge magnetism of Heisenberg model on honeycomb lattice. Sci Rep 2017; 7:43678. [PMID: 28266559 PMCID: PMC5339796 DOI: 10.1038/srep43678] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 01/30/2017] [Indexed: 11/20/2022] Open
Abstract
Edge magnetism in graphene sparks intense theoretical and experimental interests. In the previous study, we demonstrated the existence of collective excitations at the zigzag edge of the honeycomb lattice with long-ranged Néel order. By employing the Schwinger-boson approach, we show that the edge magnons remain robust even when the long-ranged order is destroyed by spin fluctuations. Furthermore, in the effective field-theory limit, the dynamics of the edge magnon is captured by the one-dimensional relativistic Klein-Gordon equation. It is intriguing that the boundary field theory for the edge magnon is tied up with its bulk counterpart. By performing density-matrix renormalization group calculations, we show that the robustness may be attributed to the closeness between the ground state and the Néel state. The existence of edge magnon is not limited to the honeycomb structure, as demonstrated in the rotated-square lattice with zigzag edges as well. The universal behavior indicates that the edge magnons may attribute to the uncompensated edges and can be detected in many two-dimensional materials.
Collapse
|
11
|
Ozaki K, Murai K, Matsuoka W, Kawasumi K, Ito H, Itami K. One‐Step Annulative π‐Extension of Alkynes with Dibenzosiloles or Dibenzogermoles by Palladium/
o
‐chloranil Catalysis. Angew Chem Int Ed Engl 2016; 56:1361-1364. [DOI: 10.1002/anie.201610374] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Revised: 11/24/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Kyohei Ozaki
- Graduate School of Science Nagoya University, Chikusa Nagoya 464-8602 Japan
| | - Keiichiro Murai
- Graduate School of Science Nagoya University, Chikusa Nagoya 464-8602 Japan
| | - Wataru Matsuoka
- Graduate School of Science Nagoya University, Chikusa Nagoya 464-8602 Japan
| | - Katsuaki Kawasumi
- Graduate School of Science Nagoya University, Chikusa Nagoya 464-8602 Japan
| | - Hideto Ito
- Graduate School of Science Nagoya University, Chikusa Nagoya 464-8602 Japan
| | - Kenichiro Itami
- Graduate School of Science Nagoya University, Chikusa Nagoya 464-8602 Japan
- Institute of Transformative Bio-Molecules (WPI-ITbM) Nagoya University, Chikusa Nagoya 464-8601 Japan
- JST-ERATO, Itami Molecular Nanocarbon Project Nagoya University, Chikusa Nagoya 464-8602 Japan
| |
Collapse
|
12
|
Ozaki K, Murai K, Matsuoka W, Kawasumi K, Ito H, Itami K. One‐Step Annulative π‐Extension of Alkynes with Dibenzosiloles or Dibenzogermoles by Palladium/
o
‐chloranil Catalysis. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201610374] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Kyohei Ozaki
- Graduate School of Science Nagoya University, Chikusa Nagoya 464-8602 Japan
| | - Keiichiro Murai
- Graduate School of Science Nagoya University, Chikusa Nagoya 464-8602 Japan
| | - Wataru Matsuoka
- Graduate School of Science Nagoya University, Chikusa Nagoya 464-8602 Japan
| | - Katsuaki Kawasumi
- Graduate School of Science Nagoya University, Chikusa Nagoya 464-8602 Japan
| | - Hideto Ito
- Graduate School of Science Nagoya University, Chikusa Nagoya 464-8602 Japan
| | - Kenichiro Itami
- Graduate School of Science Nagoya University, Chikusa Nagoya 464-8602 Japan
- Institute of Transformative Bio-Molecules (WPI-ITbM) Nagoya University, Chikusa Nagoya 464-8601 Japan
- JST-ERATO, Itami Molecular Nanocarbon Project Nagoya University, Chikusa Nagoya 464-8602 Japan
| |
Collapse
|
13
|
On-surface synthesis of graphene nanoribbons with zigzag edge topology. Nature 2016; 531:489-92. [DOI: 10.1038/nature17151] [Citation(s) in RCA: 934] [Impact Index Per Article: 116.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 01/19/2016] [Indexed: 12/23/2022]
|
14
|
Makarova TL, Shelankov AL, Zyrianova AA, Veinger AI, Tisnek TV, Lähderanta E, Shames AI, Okotrub AV, Bulusheva LG, Chekhova GN, Pinakov DV, Asanov IP, Šljivančanin Ž. Edge state magnetism in zigzag-interfaced graphene via spin susceptibility measurements. Sci Rep 2015; 5:13382. [PMID: 26307529 PMCID: PMC4549622 DOI: 10.1038/srep13382] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 07/21/2015] [Indexed: 11/09/2022] Open
Abstract
Development of graphene spintronic devices relies on transforming it into a material with a spin order. Attempts to make graphene magnetic by introducing zigzag edge states have failed due to energetically unstable structure of torn zigzag edges. Here, we report on the formation of nanoridges, i.e., stable crystallographically oriented fluorine monoatomic chains, and provide experimental evidence for strongly coupled magnetic states at the graphene-fluorographene interfaces. From the first principle calculations, the spins at the localized edge states are ferromagnetically ordered within each of the zigzag interface whereas the spin interaction across a nanoridge is antiferromagnetic. Magnetic susceptibility data agree with this physical picture and exhibit behaviour typical of quantum spin-ladder system with ferromagnetic legs and antiferromagnetic rungs. The exchange coupling constant along the rungs is measured to be 450 K. The coupling is strong enough to consider graphene with fluorine nanoridges as a candidate for a room temperature spintronics material.
Collapse
Affiliation(s)
- T L Makarova
- Lappeenranta University of Technology, FI-53851 Lappeenranta, Finland.,Ioffe Physical Technical Institute, Polytechnicheskaya 26, 194021 St. Petersburg, Russia
| | - A L Shelankov
- Ioffe Physical Technical Institute, Polytechnicheskaya 26, 194021 St. Petersburg, Russia
| | - A A Zyrianova
- Ioffe Physical Technical Institute, Polytechnicheskaya 26, 194021 St. Petersburg, Russia
| | - A I Veinger
- Ioffe Physical Technical Institute, Polytechnicheskaya 26, 194021 St. Petersburg, Russia
| | - T V Tisnek
- Ioffe Physical Technical Institute, Polytechnicheskaya 26, 194021 St. Petersburg, Russia
| | - E Lähderanta
- Lappeenranta University of Technology, FI-53851 Lappeenranta, Finland
| | - A I Shames
- Ben-Gurion University of the Negev, 84105, Beer-Sheva, Israel
| | - A V Okotrub
- Nikolaev Institute of Inorganic Chemistry SB RAS, 630060, Novosibirsk, Russia
| | - L G Bulusheva
- Nikolaev Institute of Inorganic Chemistry SB RAS, 630060, Novosibirsk, Russia
| | - G N Chekhova
- Nikolaev Institute of Inorganic Chemistry SB RAS, 630060, Novosibirsk, Russia
| | - D V Pinakov
- Nikolaev Institute of Inorganic Chemistry SB RAS, 630060, Novosibirsk, Russia
| | - I P Asanov
- Nikolaev Institute of Inorganic Chemistry SB RAS, 630060, Novosibirsk, Russia
| | - Ž Šljivančanin
- Vinča Institute of Nuclear Sciences, P.O. Box 522, RS-11001 Belgrade, Serbia
| |
Collapse
|
15
|
Magnetization due to localized states on graphene grain boundary. Sci Rep 2015; 5:11744. [PMID: 26145161 PMCID: PMC4491844 DOI: 10.1038/srep11744] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 04/24/2015] [Indexed: 11/08/2022] Open
Abstract
Magnetism in graphene has been found to originate from various defects, e.g., vacancy, edge formation, add-atoms etc. Here, we discuss about an alternate route of achieving magnetism in graphene via grain boundary. During chemical vapor deposition of graphene, several graphene nucleation centers grow independently and face themselves with unusual bonding environment, giving rise to the formation of grain boundaries. We investigate the origin of magnetism in such grain boundaries within first-principles calculations, by letting two nucleation centers interact with each other at their interface. We observe formation of unprecedented point defect, consisting of fused three-membered and larger carbon rings, which induces net magnetization to graphene quantum dots. In case of periodic lattices, the appearance of array of point defects leads to the formation of magnetic grain boundaries. The net magnetization on these defects arises due to the deviation from bipartite characteristics of pristine graphene. We observe magnetic grain boundary induced dispersion less flat bands near Fermi energy, showing higher localization of electrons. These flat bands can be accessed via small doping, leading to enhanced magnetism. Moreover, the grain boundaries can induce asymmetric spin conduction behavior along the cross boundary direction. These properties can be exploited for sensor and spin-filtering applications.
Collapse
|
16
|
Zhou H, Nie Z, Yin J, Sun Y, Zhuo H, Wang D, Li D, Dou J, Zhang X, Ma T. Antisolvent diffusion-induced growth, equilibrium behaviours in aqueous solution and optical properties of CH3NH3PbI3 single crystals for photovoltaic applications. RSC Adv 2015. [DOI: 10.1039/c5ra17579h] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Antisolvent diffusion-induced growth, equilibrium behaviours in aqueous solution and optical properties of CH3NH3PbI3 single crystals.
Collapse
|
17
|
Zhou H, Shi Y, Dong Q, Zhang H, Xing Y, Wang K, Du Y, Ma T. Hole-Conductor-Free, Metal-Electrode-Free TiO2/CH3NH3PbI3 Heterojunction Solar Cells Based on a Low-Temperature Carbon Electrode. J Phys Chem Lett 2014; 5:3241-3246. [PMID: 26276339 DOI: 10.1021/jz5017069] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Low cost, high efficiency, and stability are straightforward research challenges in the development of organic-inorganic perovskite solar cells. Organolead halide is unstable at high temperatures or in some solvents. The direct preparation of a carbon layer on top becomes difficult. In this study, we successfully prepared full solution-processed low-cost TiO2/CH3NH3PbI3 heterojunction (HJ) solar cells based on a low-temperature carbon electrode. Power conversion efficiency of mesoporous (M-)TiO2/CH3NH3PbI3/C HJ solar cells based on a low-temperature-processed carbon electrode achieved 9%. The devices of M-TiO2/CH3NH3PbI3/C HJ solar cells without encapsulation exhibited advantageous stability (over 2000 h) in air in the dark. The ability to process low-cost carbon electrodes at low temperature on top of the CH3NH3PbI3 layer without destroying its structure reduces the cost and simplifies the fabrication process of perovskite HJ solar cells. This ability also provides higher flexibility to choose and optimize the device, as well as investigate the underlying active layers.
Collapse
Affiliation(s)
- Huawei Zhou
- †State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024, China
| | - Yantao Shi
- †State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024, China
| | - Qingshun Dong
- †State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024, China
| | - Hong Zhang
- †State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024, China
| | - Yujin Xing
- †State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024, China
| | - Kai Wang
- †State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024, China
| | - Yi Du
- †State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024, China
| | - Tingli Ma
- †State Key Laboratory of Fine Chemicals, School of Chemistry, Dalian University of Technology, Dalian 116024, China
- ‡Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu, Fukuoka 808-0196, Japan
| |
Collapse
|
18
|
Ago H, Tanaka I, Ogawa Y, Yunus RM, Tsuji M, Hibino H. Lattice-oriented catalytic growth of graphene nanoribbons on heteroepitaxial nickel films. ACS NANO 2013; 7:10825-10833. [PMID: 24206265 DOI: 10.1021/nn405122r] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Graphene nanoribbons (GNRs) are a promising material for electronic applications, because quantum confinement in a one-dimensional nanostructure can potentially open the band gap of graphene. However, it is still a challenge to synthesize high-quality GNRs by a bottom-up approach without relying on lithographic techniques. In this work, we demonstrate lattice-oriented catalytic growth of single-layer GNRs on the surface of a heteroepitaxial Ni film. Catalytic decomposition of a poly(methyl methacrylate) film on the Ni(100) film at 1000 °C gives narrow nanoribbons with widths of 20-30 nm, which are aligned along either [011] or [011] directions of the Ni lattice. Furthermore, low-energy electron microscope (LEEM) analysis reveals that orientation of carbon hexagons in these GNRs is highly controlled by the underlying Ni(100) lattice, leading to the formation of zigzag edges. This heteroepitaxial approach would pave a way to synthesize nanoribbons with controlled orientation for future development of electronic devices based on graphene nanostructures.
Collapse
Affiliation(s)
- Hiroki Ago
- Institute for Materials Chemistry and Engineering (IMCE), Kyushu University , Fukuoka 816-8580, Japan
| | | | | | | | | | | |
Collapse
|
19
|
Baringhaus J, Edler F, Tegenkamp C. Edge-states in graphene nanoribbons: a combined spectroscopy and transport study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:392001. [PMID: 23945317 DOI: 10.1088/0953-8984/25/39/392001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Graphene structures of finite size are expected to reveal exceptional electronic and magnetic properties which are highly attractive for future nano-technological applications. In this study we have looked at the edge-states in graphene nanoribbons (GNR) grown by self-assembly on mesa structured SiC(0001) templates. By means of a 4-tip STM/SEM system, both local spectroscopy and lateral transport have been performed in situ on the same nanostructures. The conductance in these structures was found to be e(2)/h for temperatures up to 400 K. Scanning tunneling spectroscopy clearly reveals edge-localized states on these ribbons. The local bonding of these ribbons to their support turns out to be essential in order to preserve the metallicity of the edge-states.
Collapse
Affiliation(s)
- Jens Baringhaus
- Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstraße 2, D-30167 Hannover, Germany
| | | | | |
Collapse
|
20
|
Mizukami W, Kurashige Y, Yanai T. More π Electrons Make a Difference: Emergence of Many Radicals on Graphene Nanoribbons Studied by Ab Initio DMRG Theory. J Chem Theory Comput 2012; 9:401-7. [DOI: 10.1021/ct3008974] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wataru Mizukami
- Department of Theoretical and Computational
Molecular
Science, Institute for Molecular Science, Okazaki, Aichi 444-8585,
Japan
| | - Yuki Kurashige
- Department of Theoretical and Computational
Molecular
Science, Institute for Molecular Science, Okazaki, Aichi 444-8585,
Japan
| | - Takeshi Yanai
- Department of Theoretical and Computational
Molecular
Science, Institute for Molecular Science, Okazaki, Aichi 444-8585,
Japan
| |
Collapse
|
21
|
Dutta S, Wakabayashi K. Anomalous energy-gap behaviour of armchair BC3 ribbons due to enhanced π-conjugation. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm34881k] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|