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Bugnet M, Löffler S, Ederer M, Kepaptsoglou DM, Ramasse QM. Current opinion on the prospect of mapping electronic orbitals in the transmission electron microscope: State of the art, challenges and perspectives. J Microsc 2024; 295:217-235. [PMID: 38818951 DOI: 10.1111/jmi.13321] [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: 02/05/2024] [Revised: 05/03/2024] [Accepted: 05/08/2024] [Indexed: 06/01/2024]
Abstract
The concept of electronic orbitals has enabled the understanding of a wide range of physical and chemical properties of solids through the definition of, for example, chemical bonding between atoms. In the transmission electron microscope, which is one of the most used and powerful analytical tools for high-spatial-resolution analysis of solids, the accessible quantity is the local distribution of electronic states. However, the interpretation of electronic state maps at atomic resolution in terms of electronic orbitals is far from obvious, not always possible, and often remains a major hurdle preventing a better understanding of the properties of the system of interest. In this review, the current state of the art of the experimental aspects for electronic state mapping and its interpretation as electronic orbitals is presented, considering approaches that rely on elastic and inelastic scattering, in real and reciprocal spaces. This work goes beyond resolving spectral variations between adjacent atomic columns, as it aims at providing deeper information about, for example, the spatial or momentum distributions of the states involved. The advantages and disadvantages of existing experimental approaches are discussed, while the challenges to overcome and future perspectives are explored in an effort to establish the current state of knowledge in this field. The aims of this review are also to foster the interest of the scientific community and to trigger a global effort to further enhance the current analytical capabilities of transmission electron microscopy for chemical bonding and electronic structure analysis.
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Affiliation(s)
- M Bugnet
- CNRS, INSA Lyon, Université Claude Bernard Lyon 1, MATEIS, UMR 5510, Villeurbanne, France
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury, UK
- School of Chemical and Process Engineering, University of Leeds, Leeds, UK
| | - S Löffler
- University Service Centre for Transmission Electron Microscopy, TU Wien, Wien, Austria
| | - M Ederer
- University Service Centre for Transmission Electron Microscopy, TU Wien, Wien, Austria
| | - D M Kepaptsoglou
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury, UK
- School of Physics, Engineering and Technology, University of York, York, UK
| | - Q M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury, UK
- School of Chemical and Process Engineering, University of Leeds, Leeds, UK
- School of Physics and Astronomy, University of Leeds, Leeds, UK
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2
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Bugnet M, Ederer M, Lazarov VK, Li L, Ramasse QM, Löffler S, Kepaptsoglou DM. Imaging the Spatial Distribution of Electronic States in Graphene Using Electron Energy-Loss Spectroscopy: Prospect of Orbital Mapping. PHYSICAL REVIEW LETTERS 2022; 128:116401. [PMID: 35363018 DOI: 10.1103/physrevlett.128.116401] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 12/23/2021] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
The spatial distributions of antibonding π^{*} and σ^{*} states in epitaxial graphene multilayers are mapped using electron energy-loss spectroscopy in a scanning transmission electron microscope. Inelastic channeling simulations validate the interpretation of the spatially resolved signals in terms of electronic orbitals, and demonstrate the crucial effect of the material thickness on the experimental capability to resolve the distribution of unoccupied states. This work illustrates the current potential of core-level electron energy-loss spectroscopy towards the direct visualization of electronic orbitals in a wide range of materials, of huge interest to better understand chemical bonding among many other properties at interfaces and defects in solids.
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Affiliation(s)
- M Bugnet
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, United Kingdom
- School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
- Univ Lyon, CNRS, INSA Lyon, UCBL, MATEIS, UMR 5510, 69621 Villeurbanne, France
| | - M Ederer
- University Service Centre for Transmission Electron Microscopy, TU Wien, Wiedner Hauptstraße 8-10/E057-02, 1040 Wien, Austria
| | - V K Lazarov
- Department of Physics, University of York, York YO10 5DD, United Kingdom
| | - L Li
- Department of Physics and Astronomy, University of West Virginia, Morgantown, West Virginia 26506, USA
| | - Q M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, United Kingdom
- School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT, United Kingdom
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - S Löffler
- University Service Centre for Transmission Electron Microscopy, TU Wien, Wiedner Hauptstraße 8-10/E057-02, 1040 Wien, Austria
| | - D M Kepaptsoglou
- SuperSTEM Laboratory, SciTech Daresbury Campus, Daresbury WA4 4AD, United Kingdom
- Department of Physics, University of York, York YO10 5DD, United Kingdom
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Harizanova S, Faulques E, Corraze B, Payen C, Zając M, Wilgocka-Ślęzak D, Korecki J, Atanasova G, Stoyanova R. Composites between Perovskite and Layered Co-Based Oxides for Modification of the Thermoelectric Efficiency. MATERIALS 2021; 14:ma14227019. [PMID: 34832421 PMCID: PMC8624505 DOI: 10.3390/ma14227019] [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: 10/19/2021] [Revised: 11/06/2021] [Accepted: 11/16/2021] [Indexed: 11/16/2022]
Abstract
The common approach to modify the thermoelectric activity of oxides is based on the concept of selective metal substitution. Herein, we demonstrate an alternative approach based on the formation of multiphase composites, at which the individual components have distinctions in the electric and thermal conductivities. The proof-of-concept includes the formation of multiphase composites between well-defined thermoelectric Co-based oxides: Ni, Fe co-substituted perovskite, LaCo0.8Ni0.1Fe0.1O3 (LCO), and misfit layered Ca3Co4O9. The interfacial chemical and electrical properties of composites are probed with the means of SEM, PEEM/XAS, and XPS tools, as well as the magnetic susceptibility measurements. The thermoelectric power of the multiphase composites is evaluated by the dimensionless figure of merit, ZT, calculated from the independently measured electrical resistivity (ρ), Seebeck coefficient (S), and thermal conductivity (λ). It has been demonstrated that the magnitude's electric and thermal conductivities depend more significantly on the composite interfaces than the Seebeck coefficient values. As a result, the highest thermoelectric activity is observed at the composite richer on the perovskite (i.e., ZT = 0.34 at 298 K).
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Affiliation(s)
- Sonya Harizanova
- Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (S.H.); (G.A.)
| | - Eric Faulques
- Institut des Matériaux Jean Rouxel, University of Nantes, CNRS, IMN, F-44000 Nantes, France; (E.F.); (B.C.); (C.P.)
| | - Benoit Corraze
- Institut des Matériaux Jean Rouxel, University of Nantes, CNRS, IMN, F-44000 Nantes, France; (E.F.); (B.C.); (C.P.)
| | - Christophe Payen
- Institut des Matériaux Jean Rouxel, University of Nantes, CNRS, IMN, F-44000 Nantes, France; (E.F.); (B.C.); (C.P.)
| | - Marcin Zając
- National Synchrotron Radiation Centre Solaris, 30-392 Kraków, Poland; (M.Z.); (J.K.)
| | - Dorota Wilgocka-Ślęzak
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, 30-239 Kraków, Poland;
| | - Józef Korecki
- National Synchrotron Radiation Centre Solaris, 30-392 Kraków, Poland; (M.Z.); (J.K.)
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, 30-239 Kraków, Poland;
| | - Genoveva Atanasova
- Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (S.H.); (G.A.)
| | - Radostina Stoyanova
- Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (S.H.); (G.A.)
- Correspondence: ; Tel.: +359-2-979-3915
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Enhanced Thermoelectric Properties of Ca 3-xAg xCo₄O₉ by the Sol⁻Gel Method with Spontaneous Combustion and Cold Isostatic Pressing. MATERIALS 2018; 11:ma11122573. [PMID: 30563011 PMCID: PMC6316612 DOI: 10.3390/ma11122573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 12/07/2018] [Accepted: 12/14/2018] [Indexed: 11/24/2022]
Abstract
In this study, Ca3−xAgxCo4O9 ceramics were synthesized by the sol–gel method combined with spontaneous combustion and cold isostatic pressing. The Ca3−xAgxCo4O9 ceramics were characterized via X-ray diffraction and scanning electron microscopy. Thermoelectric properties of the ceramics were measured from 323 to 673 K. The results indicated that Ag doping significantly affected the microstructure and thermoelectric properties. With the increase in Ag content and gradual increase in electrical conductivity, the Seebeck coefficient first increased and then decreased, whereas the thermal conductivity exhibited the opposite case. The figure of merit, ZT, was 0.17 at 673 K for the Ca2.8Ag0.2Co4O9 sample. These results indicated that the thermoelectric properties could be optimized remarkably with the substitution of Ag.
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Gomes WC, Melo DM, Pimentel PM, Marinho EP, Melo MA, Nasar RS. XAS structural characterization of La 1−x A x CoO 3 doped with calcium and barium as a function of temperature. Chem Phys 2017. [DOI: 10.1016/j.chemphys.2017.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Yao W, Yang D, Yan Y, Peng K, Zhan H, Liu A, Lu X, Wang G, Zhou X. Synergistic Strategy to Enhance the Thermoelectric Properties of CoSbS 1-xSe x Compounds via Solid Solution. ACS APPLIED MATERIALS & INTERFACES 2017; 9:10595-10601. [PMID: 28282116 DOI: 10.1021/acsami.6b12796] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
High thermal conductivity of CoSbS-based limited its own prospect application in thermoelectric energy conversion. Solid solution is an effective approach to optimize the performance of thermoelectric materials with high lattice thermal conductivity because of the enhanced phonons scattering from disorder atoms. In this paper, we have synthesized and measured the thermoelectric properties of solid solution CoSbS1-xSex (x = 0, 0.05, 0.10, 0.15, 0.20, 0.30) series samples. The collaborative optimization (enhancing the power factors and reducing the thermal conductivities) to add zT values were realized via substitution of S atoms with the isoelectronic Se atoms in the matrix. Meanwhile, the lowest room temperature lattice thermal conductivity in CoSbS-based materials is obtained (4.72 W m-1 K-1) at present. Benefiting from the results of synergistic strategy, a zT of 0.35 was achieved at 923 K for sample CoSbS0.85Se0.15, a 59% improvement as compared with that of the pristine CoSbS. Band calculation demonstrated that CoSbS0.85Se0.15 present a similar band dispersion with CoSbS. The mechanism of point defect scattering for reducing the lattice thermal conductivity at room temperature, was also analyzed by the Callaway model. The contributions to decrease the room temperature lattice thermal conductivity from the mass and the strain fluctuation in the crystal are comparable. These results can also be extended to other high-efficiency thermoelectric materials with stiff bond and smaller Gruneisen parameters.
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Affiliation(s)
- Wei Yao
- College of Physics, Chongqing University , Chongqing 401331, People's Republic of China
| | - Dingfeng Yang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences , Chongqing 400714, People's Republic of China
| | - Yanci Yan
- College of Physics, Chongqing University , Chongqing 401331, People's Republic of China
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences , Chongqing 400714, People's Republic of China
| | - Kunling Peng
- College of Physics, Chongqing University , Chongqing 401331, People's Republic of China
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences , Chongqing 400714, People's Republic of China
| | - Heng Zhan
- College of Physics, Chongqing University , Chongqing 401331, People's Republic of China
| | - Anping Liu
- College of Physics, Chongqing University , Chongqing 401331, People's Republic of China
| | - Xu Lu
- College of Physics, Chongqing University , Chongqing 401331, People's Republic of China
| | - Guoyu Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences , Chongqing 400714, People's Republic of China
| | - Xiaoyuan Zhou
- College of Physics, Chongqing University , Chongqing 401331, People's Republic of China
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Li Z, Xiao C, Zhu H, Xie Y. Defect Chemistry for Thermoelectric Materials. J Am Chem Soc 2016; 138:14810-14819. [DOI: 10.1021/jacs.6b08748] [Citation(s) in RCA: 117] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Zhou Li
- Hefei National Laboratory for Physical Sciences at the Microscale, Collaborative Innovation Center of Chemistry for Energy Materials, University of Science & Technology of China, Hefei, Anhui 230026, P. R. China
| | - Chong Xiao
- Hefei National Laboratory for Physical Sciences at the Microscale, Collaborative Innovation Center of Chemistry for Energy Materials, University of Science & Technology of China, Hefei, Anhui 230026, P. R. China
| | - Hao Zhu
- Hefei National Laboratory for Physical Sciences at the Microscale, Collaborative Innovation Center of Chemistry for Energy Materials, University of Science & Technology of China, Hefei, Anhui 230026, P. R. China
| | - Yi Xie
- Hefei National Laboratory for Physical Sciences at the Microscale, Collaborative Innovation Center of Chemistry for Energy Materials, University of Science & Technology of China, Hefei, Anhui 230026, P. R. China
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Roy P, Waghmare V, Maiti T. Environmentally friendly BaxSr2−xTiFeO6double perovskite with enhanced thermopower for high temperature thermoelectric power generation. RSC Adv 2016. [DOI: 10.1039/c6ra09629h] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
SrTiO3based double perovskites, BaxSr2−xTiFeO6(BSTF) compositions showed very large thermo-power (S) for the application of high temperature thermoelectric power generation.
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Affiliation(s)
- Pinku Roy
- Plasmonics and Perovskites Laboratory
- Department of Materials Science and Engineering
- Indian Institute of Technology Kanpur
- India
| | - Vikram Waghmare
- Plasmonics and Perovskites Laboratory
- Department of Materials Science and Engineering
- Indian Institute of Technology Kanpur
- India
| | - Tanmoy Maiti
- Plasmonics and Perovskites Laboratory
- Department of Materials Science and Engineering
- Indian Institute of Technology Kanpur
- India
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Phillips PJ, Paulauskas T, Rowlands N, Nicholls AW, Low KB, Bhadare S, Klie RF. A new silicon drift detector for high spatial resolution STEM-XEDS: performance and applications. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2014; 20:1046-1052. [PMID: 25410601 DOI: 10.1017/s1431927614001639] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A newly designed, 100 mm2, silicon drift detector has been installed on an aberration-corrected scanning transmission electron microscope equipped with an ultra-high resolution pole piece, without requiring column modifications. With its unique, windowless design, the detector's active region is in close proximity to the sample, resulting in a dramatic increase in count rate, while demonstrating an increased sensitivity to low energy X-rays and a muted tilt dependence. Numerous examples of X-ray energy dispersive spectrometry are presented on relevant materials such as Al x Ga1-x N nanowires, perovskite oxides, and polycrystalline CdTe thin films, across both varying length scales and accelerating voltages.
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Affiliation(s)
- Patrick J Phillips
- 1Department of Physics,University of Illinois at Chicago,845 W Taylor Street,Chicago,IL 60607,USA
| | - Tadas Paulauskas
- 1Department of Physics,University of Illinois at Chicago,845 W Taylor Street,Chicago,IL 60607,USA
| | - Neil Rowlands
- 2Oxford Instruments NanoAnalysis,Halifax Road,High Wycombe,HP12 3SE,UK
| | - Alan W Nicholls
- 3Research Resources Center,University of Illinois at Chicago,845 W Taylor Street,Chicago,IL 60607,USA
| | - Ke-Bin Low
- 4BASF,25 Middlesex/Essex Turnpike,Iselin,NJ 08830,USA
| | - Santokh Bhadare
- 2Oxford Instruments NanoAnalysis,Halifax Road,High Wycombe,HP12 3SE,UK
| | - Robert F Klie
- 1Department of Physics,University of Illinois at Chicago,845 W Taylor Street,Chicago,IL 60607,USA
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Xiao C, Li Z, Li K, Huang P, Xie Y. Decoupling interrelated parameters for designing high performance thermoelectric materials. Acc Chem Res 2014; 47:1287-95. [PMID: 24517646 DOI: 10.1021/ar400290f] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The world's supply of fossil fuels is quickly being exhausted, and the impact of their overuse is contributing to both climate change and global political unrest. In order to help solve these escalating problems, scientists must find a way to either replace combustion engines or reduce their use. Thermoelectric materials have attracted widespread research interest because of their potential applications as clean and renewable energy sources. They are reliable, lightweight, robust, and environmentally friendly and can reversibly convert between heat and electricity. However, after decades of development, the energy conversion efficiency of thermoelectric devices has been hovering around 10%. This is far below the theoretical predictions, mainly due to the interdependence and coupling between electrical and thermal parameters, which are strongly interrelated through the electronic structure of the materials. Therefore, any strategy that balances or decouples these parameters, in addition to optimizing the materials' intrinsic electronic structure, should be critical to the development of thermoelectric technology. In this Account, we discuss our recently developed strategies to decouple thermoelectric parameters for the synergistic optimization of electrical and thermal transport. We first highlight the phase transition, which is accompanied by an abrupt change of electrical transport, such as with a metal-insulator and semiconductor-superionic conductor transition. This should be a universal and effective strategy to optimize the thermoelectric performance, which takes advantage of modulated electronic structure and critical scattering across phase transitions to decouple the power factor and thermal conductivity. We propose that solid-solution homojunction nanoplates with disordered lattices are promising thermoelectric materials to meet the "phonon glass electron crystal" approach. The formation of a solid solution, coupled with homojunctions, allows for synergistically enhanced thermoelectric properties. This occurs through a significant reduction of thermal conductivity, without the deterioration of thermopower and electrical conductivity. In addition, we introduce the concept of spin entropy in wide band gap semiconductor nanocrystals, which acts to fully disentangle the otherwise interconnected quantities for synergistically optimized thermoelectric performance. Finally, we discuss a new concept we developed that is based on an ultrathin-nanosheet composite that we fabricated from ultrathin nanosheets of atomic thickness. These retain the original strong two-dimensional electron gas (2DEG) and allow for decoupled optimization of the three thermoelectric parameters, which improves thermoelectric performance.
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Affiliation(s)
- Chong Xiao
- Hefei National Laboratory
for Physical Sciences at the Microscale and Collaborative Innovation Center of Chemistry for Energy Materials, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
| | - Zhou Li
- Hefei National Laboratory
for Physical Sciences at the Microscale and Collaborative Innovation Center of Chemistry for Energy Materials, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
| | - Kun Li
- Hefei National Laboratory
for Physical Sciences at the Microscale and Collaborative Innovation Center of Chemistry for Energy Materials, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
| | - Pengcheng Huang
- Hefei National Laboratory
for Physical Sciences at the Microscale and Collaborative Innovation Center of Chemistry for Energy Materials, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
| | - Yi Xie
- Hefei National Laboratory
for Physical Sciences at the Microscale and Collaborative Innovation Center of Chemistry for Energy Materials, University of Science and Technology of China, Hefei, Anhui 230026, People’s Republic of China
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