1
|
Ekren D, Cao J, Azough F, Kepaptsoglou D, Ramasse Q, Kinloch IA, Freer R. Controlling the Thermoelectric Behavior of La-Doped SrTiO 3 through Processing and Addition of Graphene Oxide. ACS APPLIED MATERIALS & INTERFACES 2022; 14:53711-53723. [PMID: 36413504 PMCID: PMC9743083 DOI: 10.1021/acsami.2c14408] [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: 08/10/2022] [Accepted: 11/01/2022] [Indexed: 06/16/2023]
Abstract
The addition of graphene has been reported as a potential route to enhance the thermoelectric performance of SrTiO3. However, the interplay between processing parameters and graphene addition complicates understanding this enhancement. Herein, we examine the effects of processing parameters and graphene addition on the thermoelectric performance of La-doped SrTiO3 (LSTO). Briefly, two types of graphene oxide (GO) at different oxidation degrees were used, while the LSTO pellets were densified under two conditions with different reducing strengths (with/without using oxygen-scavenging carbon powder bed muffling). Raman imaging of the LSTO green body and sintered pellets suggests that the added GO sacrificially reacts with the lattice oxygen, which creates more oxygen vacancies and improves electrical conductivity regardless of the processing conditions. The addition of mildly oxidized electrochemical GO (EGO) yields better performance than the conventional heavily oxidized chemical GO (CGO). Moreover, we found that muffling the green body with an oxygen-scavenging carbon powder bed during sintering is vital to achieving a single-crystal-like temperature dependence of electrical conductivity, implying that a highly reducing environment is critical for eliminating the grain boundary barriers. Combining 1.0 wt % EGO addition with a highly reducing environment leads to the highest electrical conductivity of 2395 S cm-1 and power factor of 2525μW m-1 K-2 at 300 K, with an improved average zT value across the operating temperature range of 300-867 K. STEM-EELS maps of the optimized sample show a pronounced depletion of Sr and evident deficiency of O and La at the grain boundary region. Theoretical modeling using a two-phase model implies that the addition of GO can effectively improve carrier mobility in the grain boundary phase. This work provides guidance for the development of high-performance thermoelectric ceramic oxides.
Collapse
Affiliation(s)
- Dursun Ekren
- Department
of Materials, University of Manchester, Oxford Road, ManchesterM13 9PL, U.K.
- Department
of Metallurgical and Materials Engineering, Iskenderun Technical University, İskenderun31200, Hatay, Turkey
| | - Jianyun Cao
- Department
of Materials, University of Manchester, Oxford Road, ManchesterM13 9PL, U.K.
- Key
Laboratory of LCR Materials and Devices of Yunnan Province, School
of Materials Science and Energy, Yunnan
University, Kunming650500, China
| | - Feridoon Azough
- Department
of Materials, University of Manchester, Oxford Road, ManchesterM13 9PL, U.K.
| | - Demie Kepaptsoglou
- SuperSTEM
Laboratory, SciTech Daresbury Campus, Daresbury, WarringtonWA4
4AD, U.K.
- Department
of Physics, University of York, YorkYO10 5DD, U.K.
| | - Quentin Ramasse
- SuperSTEM
Laboratory, SciTech Daresbury Campus, Daresbury, WarringtonWA4
4AD, U.K.
- School of
Chemical and Process Engineering, University
of Leeds, LeedsLS2 9JT, U.K.
| | - Ian A. Kinloch
- Department
of Materials, University of Manchester, Oxford Road, ManchesterM13 9PL, U.K.
- Henry
Royce Institute and National Graphene Institute, University of Manchester, Oxford Road, ManchesterM13 9PL, U.K.
| | - Robert Freer
- Department
of Materials, University of Manchester, Oxford Road, ManchesterM13 9PL, U.K.
| |
Collapse
|
2
|
Aydin A, Sisman A, Fransson J, Black-Schaffer AM, Dutta P. Thermodefect voltage in graphene nanoribbon junctions. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:195304. [PMID: 35168226 DOI: 10.1088/1361-648x/ac553b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 02/15/2022] [Indexed: 06/14/2023]
Abstract
Thermoelectric junctions are often made of components of different materials characterized by distinct transport properties. Single material junctions, with the same type of charge carriers, have also been considered to investigate various classical and quantum effects on the thermoelectric properties of nanostructured materials. We here introduce the concept of defect-induced thermoelectric voltage, namely,thermodefect voltage, in graphene nanoribbon (GNR) junctions under a temperature gradient. Our thermodefect junction is formed by two GNRs with identical properties except the existence of defects in one of the nanoribbons. At room temperature the thermodefect voltage is highly sensitive to the types of defects, their locations, as well as the width and edge configurations of the GNRs. We computationally demonstrate that the thermodefect voltage can be as high as 1.7 mV K-1for 555-777 defects in semiconducting armchair GNRs. We further investigate the Seebeck coefficient, electrical conductance, and electronic thermal conductance, and also the power factor of the individual junction components to explain the thermodefect effect. Taken together, our study presents a new pathway to enhance the thermoelectric properties of nanomaterials.
Collapse
Affiliation(s)
- Alhun Aydin
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, United States of America
| | - Altug Sisman
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
| | - Jonas Fransson
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
| | | | - Paramita Dutta
- Department of Physics and Astronomy, Uppsala University, Box 516, S-751 20 Uppsala, Sweden
- Theoretical Physics Division, Physical Research Laboratory, Ahmedabad-380009, India
- Department of Physics, Birla Institute of Technology and Science-Pilani, Rajasthan-333031, India
| |
Collapse
|
3
|
Lim G, Kihm KD, Kim HG, Lee W, Lee W, Pyun KR, Cheon S, Lee P, Min JY, Ko SH. Enhanced Thermoelectric Conversion Efficiency of CVD Graphene with Reduced Grain Sizes. NANOMATERIALS 2018; 8:nano8070557. [PMID: 30037140 PMCID: PMC6071277 DOI: 10.3390/nano8070557] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 07/08/2018] [Accepted: 07/16/2018] [Indexed: 11/18/2022]
Abstract
The grain size of CVD (Chemical Vapor Deposition) graphene was controlled by changing the precursor gas flow rates, operation temperature, and chamber pressure. Graphene of average grain sizes of 4.1 µm, 2.2 µm, and 0.5 µm was synthesized in high quality and full coverage. The possibility to tailor the thermoelectric conversion characteristics of graphene has been exhibited by examining the grain size effect on the three elementary thermal and electrical properties of σ, S, and k. Electrical conductivity (σ) and Seebeck coefficients (S) were measured in a vacuum for supported graphene on SiO2/Si FET (Field Effect Transistor) substrates so that the charge carrier density could be changed by applying a gate voltage (VG). Mobility (µ) values of 529, 459, and 314 cm2/V·s for holes and 1042, 745, and 490 cm2/V·s for electrons for the three grain sizes of 4.1 µm, 2.2 µm, and 0.5 µm, respectively, were obtained from the slopes of the measured σ vs. VG graphs. The power factor (PF), the electrical portion of the thermoelectric figure of merit (ZT), decreased by about one half as the grain size was decreased, while the thermal conductivity (k) decreased by one quarter for the same grain decrease. Finally, the resulting ZT increased more than two times when the grain size was reduced from 4.1 µm to 0.5 µm.
Collapse
Affiliation(s)
- Gyumin Lim
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 08826, Korea.
| | - Kenneth David Kihm
- Department of Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, Knoxville, TN 37996, USA.
| | - Hong Goo Kim
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 08826, Korea.
| | - Woorim Lee
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 08826, Korea.
| | - Woomin Lee
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 08826, Korea.
| | - Kyung Rok Pyun
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 08826, Korea.
| | - Sosan Cheon
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 08826, Korea.
| | - Phillip Lee
- Korea Institute of Science and Technology, Seoul 02792, Korea.
| | - Jin Young Min
- School of Mechanical Engineering, Korea University, Seoul 02841, Korea.
| | - Seung Hwan Ko
- School of Mechanical and Aerospace Engineering, Seoul National University, Seoul 08826, Korea.
- Institute of Advanced Machinery and Design (SNU-IAMD), Seoul National University, Gwanak-ro, Gwanak-gu, Seoul 08826, Korea.
| |
Collapse
|
4
|
Mu X, Wu X, Zhang T, Go DB, Luo T. Thermal transport in graphene oxide--from ballistic extreme to amorphous limit. Sci Rep 2014; 4:3909. [PMID: 24468660 PMCID: PMC3904152 DOI: 10.1038/srep03909] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 01/13/2014] [Indexed: 12/23/2022] Open
Abstract
Graphene oxide is being used in energy, optical, electronic and sensor devices due to its unique properties. However, unlike its counterpart - graphene - the thermal transport properties of graphene oxide remain unknown. In this work, we use large-scale molecular dynamics simulations with reactive potentials to systematically study the role of oxygen adatoms on the thermal transport in graphene oxide. For pristine graphene, highly ballistic thermal transport is observed. As the oxygen coverage increases, the thermal conductivity is significantly reduced. An oxygen coverage of 5% can reduce the graphene thermal conductivity by ~90% and a coverage of 20% lower it to ~8.8 W/mK. This value is even lower than the calculated amorphous limit (~11.6 W/mK for graphene), which is usually regarded as the minimal possible thermal conductivity of a solid. Analyses show that the large reduction in thermal conductivity is due to the significantly enhanced phonon scattering induced by the oxygen defects which introduce dramatic structural deformations. These results provide important insight to the thermal transport physics in graphene oxide and offer valuable information for the design of graphene oxide-based materials and devices.
Collapse
Affiliation(s)
- Xin Mu
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Xufei Wu
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Teng Zhang
- Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - David B Go
- 1] Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA [2] Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Tengfei Luo
- 1] Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556, USA [2] Center for Sustainable Energy at Notre Dame, University of Notre Dame, Notre Dame, Indiana 46556, USA
| |
Collapse
|
5
|
Balandin AA. Thermal properties of graphene and nanostructured carbon materials. NATURE MATERIALS 2011; 10:569-81. [PMID: 21778997 DOI: 10.1038/nmat3064] [Citation(s) in RCA: 1683] [Impact Index Per Article: 129.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Recent years have seen a rapid growth of interest by the scientific and engineering communities in the thermal properties of materials. Heat removal has become a crucial issue for continuing progress in the electronic industry, and thermal conduction in low-dimensional structures has revealed truly intriguing features. Carbon allotropes and their derivatives occupy a unique place in terms of their ability to conduct heat. The room-temperature thermal conductivity of carbon materials span an extraordinary large range--of over five orders of magnitude--from the lowest in amorphous carbons to the highest in graphene and carbon nanotubes. Here, I review the thermal properties of carbon materials focusing on recent results for graphene, carbon nanotubes and nanostructured carbon materials with different degrees of disorder. Special attention is given to the unusual size dependence of heat conduction in two-dimensional crystals and, specifically, in graphene. I also describe the prospects of applications of graphene and carbon materials for thermal management of electronics.
Collapse
Affiliation(s)
- Alexander A Balandin
- Department of Electrical Engineering and Materials Science and Engineering Program, Bourns College of Engineering, University of California, Riverside, California 92521, USA.
| |
Collapse
|
6
|
Bhargavi KS, Kubakaddi SS. Phonon-drag thermopower in an armchair graphene nanoribbon. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:275303. [PMID: 21697579 DOI: 10.1088/0953-8984/23/27/275303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We calculate the phonon-drag thermopower S(g) of an armchair graphene nanoribbon (AGNR) in the boundary scattering regime of phonons. S(g) is studied as a function of temperature, Fermi energy and width of the AGNR. At very low temperatures T, S(g) is exponentially suppressed and an activated behavior is observed which is characteristic of one-dimensional carriers. This is in contrast to the power law dependence in graphene in the Bloch-Grüneisen regime. However, at higher T, S(g) in the AGNR levels off. S(g) also shows strong dependence on Fermi energy and width of the AGNR. The magnitude of S(g) in the AGNR is compared with that in single-wall carbon nanotube and graphene.
Collapse
Affiliation(s)
- K S Bhargavi
- Department of Physics, Karnatak University, Dharwad-580 003, Karnataka, India
| | | |
Collapse
|