synthesis, characterization, and performance by corey alan hewi

227 Pages·2013·10.1 MB·English

LOW DIMENSIONAL CARBON BASED ORGANIC THERMOELECTRIC
COMPOSITES: SYNTHESIS, CHARACTERIZATION, AND PERFORMANCE

BY

COREY ALAN HEWITT

A Dissertation Submitted to the Graduate Faculty of

WAKE FOREST UNIVERSITY GRADUATE SCHOOL OF ARTS AND SCIENCES

in Partial Fulfillment of the Requirements

for the Degree of

DOCTOR OF PHILOSOPHY

Physics

December 2013

Winston-Salem, North Carolina

Approved By

David L. Carroll, Ph.D., Advisor

Abdessadek Lachgar, Ph.D., Chair

Paul R. Anderson, Ph.D.

Oana D. Jurchescu, Ph.D.

Jed C. Macosko, Ph.D.
DEDICATION AND ACKNOWLEDGEMENTS

First and foremost I would like to thank Dr. David Carroll for the guidance and
wisdom he shared with me as my advisor during my graduate studies, as well as the
immense effort he provides to keep the Center for Nanotechnology funded so we have the
space, materials, and equipment needed to conduct our research. I would also like to
thank my collaborators Dr. Alan Kaiser and Dr. Siegmar Roth for their many discussions
on data that lead us to unexplored avenues within our field. I also extend gratitude to Dr.
Richard Czerw and Matt Craps for kindly providing me with all the modified carbon
based materials I requested of them. Appreciation and encouragement is also in order for
David Montgomery for his interest in the project as he takes over as lead graduate student
with the assistance of our dedicated undergraduate students Ryan Barbalace and Rowland
Carlson. Finally, I would like to share my sincerest adoration for my wife Karen for
always believing in me and encouraging me, particularly during the times I let data
analysis get the best of me.
Corey A. Hewitt

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ii
TABLE OF CONTENTS

LIST OF FIGURES ........................................................................................................... vi
LIST OF ABBREVIATIONS ............................................................................................ ix
ABSTRACT ...................................................................................................................... xii
CHAPTER
1. INTRODUCTION ...................................................................................................1
1.1 Thermoelectric Effects and Measurement ......................................................................... 2
1.2 Carbon Nanotube Thermoelectric Properties ................................................................. 17
1.3 Motivation ....................................................................................................................... 24

2. NEGATIVE THERMOELECTRIC POWER FROM LARGE DIAMETER
MULTIWALLED CARBON NANOTUBES GROWN AT HIGH CHEMICAL
VAPOR DEPOSITION TEMPERATURES .........................................................35

C. A. Hewitt, A. B. Kaiser, M. Craps, R. Czerw, and D. L. Carroll, Journal of
Applied Physics 114, 083701 (2013)

2.1 Introduction .................................................................................................................... 36
2.2 Experimental ................................................................................................................... 38
2.3 Results / Discussion ........................................................................................................ 39
2.4 Conclusion ...................................................................................................................... 49

3. THE EFFECTS OF HIGH ENERGY PROBE SONICATION ON THE
THERMOELECTRIC POWER OF LARGE DIAMETER MULTIWALLED
CARBON NANOTUBES SYNTHESIZED BY CHEMICAL VAPOR
DEPOSITION ........................................................................................................55

C. A. Hewitt, M. Craps, R. Czerw, and D. L. Carroll, Synthetic Metals 184 (cover
article), 68-72 (2013)

3.1 Introduction .................................................................................................................... 56
3.2 Experimental ................................................................................................................... 58
3.3 Results / Discussion ........................................................................................................ 59
3.4 Conclusion ...................................................................................................................... 67

4. THE EFFECTS OF ACID TREATMENT ON THE THERMOELECTRIC
POWER OF MULTIWALLED CARBON NANOTUBES SYNTHESIZED BY
CHEMICAL VAPOR DEPOSITION....................................................................72

C. A. Hewitt, and D. L. Carroll, Chemical Physics Letters 580, 67-72 (2013)
4.1 Introduction .................................................................................................................... 73
4.2 Experimental ................................................................................................................... 74
4.3 Results ............................................................................................................................. 76
4.4 Discussion ....................................................................................................................... 82
4.5 Conclusion ...................................................................................................................... 87
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iii
5. VARYING THE CONCENTRATION OF SINGLE WALLED CARBON
NANOTUBES IN THIN FILM POLYMER COMPOSITES, AND ITS EFFECT
ON THERMOELECTRIC POWER ......................................................................93

C. A. Hewitt, A. B. Kaiser, S. Roth, M. Craps, R. Czerw, and D. L. Carroll, Applied
Physics Letters 98, 183110 (2011)

5.1 Introduction .................................................................................................................... 94
5.2 Experimental ................................................................................................................... 96
5.3 Results / Discussion ........................................................................................................ 97
5.4 Conclusion .................................................................................................................... 101

6. TEMPERATURE DEPENDENT THERMOELECTRIC PROPERTIES OF
SINGLE AND MULTI- WALLED CARBON NANOTUBE BASED POLYMER
COMPOSITES .....................................................................................................106

C. A. Hewitt and D. L. Carroll, Journal of Nano Energy and Power Research,
accepted (2013)

6.1 Introduction .................................................................................................................. 107
6.2 Experimental ................................................................................................................. 109
6.3 Results ........................................................................................................................... 111
6.4 Discussion ..................................................................................................................... 115
6.5 Conclusion .................................................................................................................... 117

7. TEMPERATURE DEPENDENT THERMOELECTRIC PROPERTIES OF
POLYETHYLENIMINE DOPED SINGLE WALLED CARBON NANOTUBE
BASED POLYMER COMPOSITES ..................................................................122

C. A. Hewitt, A. B. Kaiser, and D. L. Carroll, submitted (2013)

7.1 Introduction .................................................................................................................. 123
7.2 Experimental ................................................................................................................. 125
7.3 Results ........................................................................................................................... 127
7.4 Discussion ..................................................................................................................... 130
7.5 Conclusion .................................................................................................................... 134

8. TEMPERATURE DEPENDENT THERMOELECTRIC PROPERTIES OF
FREESTANDING FEW LAYER GRAPHENE/ POLYVINYLIDENE
FLUORIDE COMPOSITE THIN FILMS ...........................................................139

C. A. Hewitt, A. B. Kaiser, M. Craps, R. Czerw, S. Roth, D. L. Carroll, Synthetic
Metals 165 (cover article), 56-59 (2013)

8.1 Introduction .................................................................................................................. 140
8.2 Experimental ................................................................................................................. 141
8.3 Results / Discussion ...................................................................................................... 142
8.4 Conclusion .................................................................................................................... 149

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iv
9. EXTRINSIC PROPERTIES AFFECTING THE THERMOELECTRIC POWER
OUTPUT OF FEW LAYER GRAPHENE/ POLYVINYLIDENE FLUORIDE
COMPOSITE THIN FILMS................................................................................154

C. A. Hewitt and D. L. Carroll, Synthetic Metals 162, 2379-2382 (2012)
9.1 Introduction .................................................................................................................. 155
9.2 Experimental ................................................................................................................. 157
9.3 Results ........................................................................................................................... 158
9.4 Discussion ..................................................................................................................... 163
9.5 Conclusion .................................................................................................................... 164

10. MULTILAYERED CARBON NANOTUBE/ POLYMER COMPOSITE BASED
THERMOELECTRIC FABRICS ........................................................................168

C. A. Hewitt, A. B. Kaiser, S. Roth, M. Craps, R. Czerw, and D. L. Carroll, Nano
Letters 12, 1307-1310 (2012)

10.1 Introduction .................................................................................................................. 169
10.2 Experimental ................................................................................................................. 171
10.3 Results / Discussion ...................................................................................................... 173
10.4 Conclusion .................................................................................................................... 178

11. IMPROVED THERMOELECTRIC POWER OUTPUT FROM MULTI-
LAYERED POLYETHYLENIMINE DOPED CARBON NANOTUBE BASED
ORGANIC COMPOSITES .................................................................................181

C. A. Hewitt, D. S. Montgomery, R. Barbalace, R. Carlson, and D. L. Carroll,
submitted (2013)

11.1 Introduction .................................................................................................................. 182
11.2 Experimental ................................................................................................................. 185
11.3 Results / Discussion ...................................................................................................... 187
11.4 Conclusion .................................................................................................................... 193

12. CONCLUSION ....................................................................................................197
12.1 Perspective .................................................................................................................... 198
12.2 Overall Implications ..................................................................................................... 198
12.3 Future Outlook .............................................................................................................. 203

APPENDIX ......................................................................................................................204
System Calibration ............................................................................................................................... 204
Chapter 7 Supplementary Information ................................................................................................. 206
Chapter 8 Supplementary Information ................................................................................................. 208
Chapter 10 Supplementary Information ............................................................................................... 209

CURRICULUM VITAE ..................................................................................................211
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LIST OF FIGURES

1.1 Circuit diagram used to explain thermoelectric effects .....................................3
1.2 Simplified thermoelectric band diagram ............................................................6
1.3 Relationship between thermoelectric parameters ............................................11
1.4 Experimental measurement setup ....................................................................13
1.5 Bulk thermoelectric device structure ...............................................................14
1.6 Thermoelectric band diagram for thermocouple ..............................................15
1.7 Multilayered thermoelectric device structure ..................................................16
1.8 Graphene structure and parameter definitions .................................................18
1.9 Carbon nanotube chiral vector definition ........................................................19
1.10 Carbon nanotube buckypaper ..........................................................................20
2.1 Multiwalled carbon nanotube micrographs .....................................................39
2.2 Multiwalled carbon nanotube diameter distributions ......................................41
2.3 X-ray photoelectron spectroscopy of multiwalled carbon nanotubes ..............42
2.4 Seebeck coefficient versus chemical vapor growth temperature .....................44
2.5 Temperature dependent Seebeck coefficient of multiwalled nanotubes ..........45
3.1 Micrographs of probe sonicated multiwalled carbon nanotubes .....................60
3.2 Electrical conductivities of probe sonicated multiwalled nanotubes ...............61
3.3 Seebeck coefficients of probe sonicated multiwalled nanotubes .....................63
4.1 Seebeck coefficients after presonication dispersion ........................................77
4.2 Seebeck coefficients and electrical conductivities after reflux treatment ........79
4.3 X-ray photoelectron spectroscopy of reflux treated carbon nanotubes ...........80
4.4 Seebeck coefficients after post-reflux processing steps ...................................81
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vi
5.1 Micrographs of single walled nanotube composites ........................................97
5.2 Electrical conductivity versus temperature for nanotube composites ..............99
5.3 Seebeck coefficient versus temperature for nanotube composites ................100
6.1 Micrographs of single and multi- walled nanotube composites ....................112
6.2 Electrical conductivity versus nanotube concentration and temperature .......113
6.3 Seebeck coefficient versus nanotube concentration and temperature ............114
7.1 Micrographs of as-synthesized and doped carbon nanotubes ........................125
7.2 Electrical conductivity for n-doped carbon nanotubes ..................................128
7.3 Room temperature Seebeck coefficients for n-doped carbon nanotubes .......129
7.4 Temperature dependent thermopower for doped carbon nanotubes ..............130
8.1 Few layer graphene scanning electron micrographs ......................................143
8.2 X-ray photoelectron spectroscopy of few layer graphene .............................144
8.3 Electrical conductivity of few layer graphene composites ............................145
8.4 Seebeck coefficient of few layer graphene composites .................................147
8.5 Power factor of few layer graphene composites ............................................149
9.1 Dimension dependent thermoelectric power experimental setup ..................158
9.2 Thermoelectric voltage and power versus absolute temperature ...................159
9.3 Thermoelectric voltage and power versus temperature difference ................160
9.4 Thermoelectric voltage and power versus load resistance .............................161
9.5 Thermoelectric power and internal resistance versus sample dimensions .....162
10.1 Multilayered thermoelectric composite schematic ........................................172
10.2 Thermoelectric voltage of a multilayered nanotube composite .....................173
10.3 Temperature dependent properties of multilayered nanotube composites ....175
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vii
10.4 Scanning electron micrographs of the inter-layer junction ............................176
10.5 Power output of a multilayered nanotube composite .....................................177
11.1 Multilayered thermoelectric schematic ..........................................................184
11.2 Thermoelectric voltage versus the number of module thermocouples ..........187
11.3 Thermoelectric power versus load resistance for multilayered module ........189
11.4 Thermoelectric power versus temperature gradient .......................................191
11.5 Multiple module device power output ...........................................................192
S1 Thermoelectric voltage for chromel and constantan standards ......................204
S2 Scanning electron micrographs of few layer graphene composites ...............208
S3 Dependence of thermoelectric voltage on temperature gradient profile ........209

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LIST OF ABBREVIATIONS

Bi Te bismuth telluride
2 3
CNT carbon nanotube
COP coefficient of performance
CVD chemical vapor deposition
DI H O deionized water
2
DMA dimethylacetamide
DMF dimethylformamide
DMSO dimethylsulfoxide
DOS density of states
DWNT double walled carbon nanotube
e electrons
FAT fluctuation assisted tunneling
FLG few layer graphene
h holes
H SO sulfuric acid
2 4
HCL hydrochloric acid
HE high energy
HiPco high pressure carbon monoxide conversion
HNO nitric acid
3
L sample length
MEK methyl ethyl ketone
MWNT multiwalled carbon nanotube
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NMP n-methyl-2-pyrrolidone
PEDOT poly(3,4-ethylenedioxythiophene)
PEI polyethylenimine
PEMA poly(ethyl methacrylate)
PF power factor
PMMA poly(methyl methacrylate)
PS polystyrene
P thermoelectric power output
TE
PTFE polytetrafluoroethylene
PVa poly(vinyl alcohol)
PVDF polyvinylidene fluoride
R internal resistance
i
R load resistance
L
RT room temperature
SDBS dodecylbenzenesulphonate
SEM scanning electron microscope
SWNT single walled carbon nanotube
t sample thickness
T absolute temperature
T cold block temperature
c
T Debye temperature
D
TE thermoelectric
TEC thermoelectric cooling
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