Thin Film Structures in Energy Applications (eBook)

Dr Suresh Babu Krishna Moorthy has dual Master’s in Science (Chemistry) and Engineering (Materials Science). He completed his Ph.D. from Indian Institute of Technology – Madras (IITM), India in 2005 and has been working in the area of nanostructures since 2000. He was working with University of Central Florida, USA (2006-2010) before joining as Assistant Professor with Centre for Nanoscience and Technology, Pondicherry University, Puducherry. His current research focuses on thin films for solid oxide fuel cells and high temperature oxidation protection of components. In addition he is also interested on the development of multifunctional nanostructures for theranostic applications.

Preface 6
Acknowledgements 8
Contents 10
Contributors 12
Chapter 1: Thin Film: Deposition, Growth Aspects, and Characterization 14
1.1 Introduction 14
1.2 Classification of Deposition Technique 15
1.3 Physical Vapour Deposition Technique 16
1.3.1 Vaporization Process 17
1.4 Classifications of PVD 19
1.4.1 Thermal Process 19
1.4.1.1 Thermal Deposition Technique 19
1.4.1.2 Electron Beam Deposition Technique 21
1.4.1.3 Molecular Beam Epitaxy 22
1.4.1.4 Pulsed Laser Deposition Technique 23
1.4.2 Athermal Process 25
1.4.2.1 Direct Current Diode (DC) Sputtering 25
1.4.2.2 Radio Frequency (RF) Sputtering 27
1.4.2.3 Magnetron Sputtering 27
1.4.2.4 Unbalanced Magnetron Sputtering 28
1.5 Thin Film Growth Mechanism in PVD 29
1.5.1 Island Growth (Volmer Weber) 29
1.5.2 Layer-by-Layer Growth (Frank-van der Merwe) 29
1.5.3 Mixed Growth (Stranski-Krastanov) 30
1.6 Chemical Vapour Deposition Technique 31
1.6.1 Gas Transportation Process 32
1.6.2 Thermally Activated Chemical Vapour Deposition 33
1.6.3 Plasma-Enhanced Chemical Vapour Deposition 34
1.6.4 Photo-Assisted Chemical Vapour Deposition 36
1.6.5 Metal Organic Chemical Vapour Deposition 36
1.7 Thin Film Characterization 37
1.7.1 Importance of Thin Film Characterization 37
1.8 Structural Characterization 37
1.8.1 X-Ray Diffraction 38
1.8.2 Grazing Incidence X-Ray Diffraction 40
1.8.3 Textured Film Analysis 42
1.8.4 X-Ray Reflectivity 42
1.8.5 Scanning Electron Microscopy 44
1.8.6 Transmission Electron Microscopy 46
1.8.7 Elemental Identification and Quantification 48
1.8.8 Atomic Force Microscopy 49
1.8.9 Profilometer 50
1.9 Mechanical Characterization 51
1.9.1 Microtensile Testing 51
1.9.2 Bulge Testing 52
1.9.3 Nanoindentation 52
1.10 Optical Characterization 53
1.10.1 Ultraviolet-Visible (UV-Vis) Spectroscopy 53
1.10.2 Photoluminescence Spectroscopy 55
1.11 Electrical Characterization 56
1.11.1 Electrical Conductivity 56
1.11.2 Electrochemical Impedance Spectroscopy 57
1.11.3 Cyclic Voltammetry 60
References 61
Chapter 2: Coatings for Energy Applications 63
2.1 Introduction 63
2.2 Advanced Coating Materials for Energy Applications 65
2.3 Thin Film and Thick Coating Fabrication Methods 67
2.4 Coatings for Solar Cells 69
2.5 Coatings for Fuel Cells 74
2.6 Coatings for Batteries 77
2.7 Coatings for Supercapacitors 81
2.8 Coatings for Fossil Fuels-Based Energy 83
2.9 Coatings for Nuclear Energy 86
2.10 Coatings for Wind Energy 87
2.11 Coatings for Hydro Energy 89
2.12 Coatings for Geothermal Energy 90
2.13 Future Trends in Coatings 91
References 91
Chapter 3: Ternary and Quaternary Semiconducting Compounds Thin Film Solar Cells 97
3.1 Introduction 97
3.2 Classifications into Different Generations of Solar Cells 98
3.2.1 Inorganic Solar Cells 99
3.2.2 First-Generation Solar Cells 100
3.2.3 Second-Generation Thin Film Solar Cells 101
3.2.3.1 Amorphous Silicon Cells 101
3.2.3.2 Binary and Ternary Compounds for Solar Cells 101
Derivation of Compound Semiconductors for Absorbers in Solar Cells 101
Cadmium Telluride 102
Copper Indium Diselenide 102
Ordered Defect Compounds 103
CuIn3Se5 104
Cu(In,Ga)Se2 104
CZTS and Related Compounds in Thin Film Solar Cells 105
3.2.4 Routes for Enhancement of Performance in Thin Film Solar Cells 106
3.2.5 Third- and Fourth-Generation Solar Cells 106
3.3 Conclusion 107
References 107
Chapter 4: Organic Semiconductors: A New Future of Nanodevices and Applications 109
4.1 Introduction: Transformation from Inorganic to Organic 110
4.2 Organic Semiconductors 111
4.2.1 Atomic Orbitals 111
4.2.2 Molecular Orbitals and Bonds 111
4.2.3 Hybridization 113
4.2.4 Electronic Structure of Conjugated Materials 114
4.2.5 Molecules/Polymers 115
4.3 Charge Transport in Organic Materials: Models and Theories 116
4.3.1 The Polaron Model 117
4.3.2 Multiple Traps and Release (MTR) Model 118
4.3.3 Variable Range Hopping Model 118
4.4 Organic Thin Film Deposition Techniques 119
4.4.1 Self-Assembly 119
4.4.2 Vacuum Evaporation 119
4.4.3 Spin-Coating 120
4.4.4 Layer-by-Layer Electrostatic Deposition 120
4.4.5 Langmuir-Blodgett Technique 121
4.4.6 Physical Vapor Deposition 121
4.4.7 Chemical Vapor Deposition 121
4.5 Organic Thin Film Devices 122
4.5.1 Organic Thin Film Transistors 122
4.5.1.1 Working Principles and Equations of Organic FETs 122
4.5.1.2 Basic Structures 123
4.5.1.3 Parameters Affecting OTFTs 124
4.5.1.4 Current Progress and Future Developments 125
4.5.2 Organic Solar Cells (OSCs) 126
4.5.2.1 Basic Processes in Organic Solar Cells 128
4.5.2.2 Types of Organic Solar Cell 130
4.5.2.3 Current Progress and Future Developments 134
4.5.3 Organic Light-Emitting Diodes 135
4.5.3.1 Mechanism 136
4.5.3.2 Small Molecule OLEDs 137
4.5.3.3 Polymer Light-Emitting Diodes 138
4.5.3.4 Current Progress and Future Developments 138
4.6 Applications of Organic Thin Film Devices 139
References 139
Chapter 5: Titania Nano-architectures for Energy 141
5.1 Introduction 141
5.2 One-Dimensional Architectures of TiO2 143
5.3 Structure 144
5.4 Electrical and Electronic Properties 145
5.5 Synthesis of One-Dimensional TiO2 Nano-architectured Coatings 145
5.5.1 Sol-Gel-Assisted Synthesis 146
5.5.2 Hydrothermal Synthesis 147
5.5.3 Electrospinning 148
5.5.4 Electrochemical Oxidation 148
5.5.4.1 Mechanistic Aspect of Formation of TiO2 Nanotube Arrays 149
5.6 Photocatalytic and Photovoltaic Applications of TiO2 Nano-architectures 153
5.6.1 Photocatalytic Properties 153
5.6.1.1 Mechanism 153
5.6.1.2 Limitations 155
5.7 Modification of Pristine TiO2 155
5.7.1 Noble Metal Loading 156
5.7.2 Semiconductor Coupling 157
5.7.3 Dye Sensitization 157
5.7.4 Cation Doping 158
5.7.5 Anion Doping 158
5.8 Photocatalytic Hydrogen Generation 160
5.9 Dye-Sensitized Solar Cell 163
5.9.1 Theory of DSSC 163
References 166
Chapter 6: State-of-the-Art Thin Film Electrolytes for Solid Oxide Fuel Cells 178
6.1 Introduction 178
6.1.1 Background of Solid Oxide Fuel Cells (SOFC) 178
6.1.2 Role of Thin Films in State-of-the-Art SOFC 182
6.2 Zirconia-Based Thin Film Electrolytes 184
6.2.1 Yttria-Stabilized Zirconia 186
6.2.2 Scandia-Stabilized Zirconia 189
6.3 Ceria-Based Thin Film Electrolytes 194
6.3.1 Gadolinia-Doped Ceria 196
6.3.2 Samaria-Doped Ceria 201
6.4 Multilayer Hetero-Structured Thin Film Electrolytes 206
6.4.1 Gadolinia-Doped Ceria and Zirconia 208
6.4.2 Samaria-Doped Ceria/Yttria-Stabilized Zirconia 211
6.5 Summary 213
References 215
Chapter 7: Thin Film Thermoelectric Materials for Sensor Applications: An Overview 226
7.1 Introduction to Thermoelectric Effects 227
7.1.1 Seebeck Effect 227
7.1.2 Peltier Effect 227
7.1.3 Thomson Effect 228
7.1.4 Thermoelectric Figure of Merit (zT) 229
7.2 Transport Properties 229
7.2.1 Seebeck Coefficient 230
7.2.2 Electrical Resistivity 231
7.2.3 Thermal Conductivity 231
7.3 Improvement of Thermoelectric Figure of Merit 232
7.4 Enhancement of zT for Low-Dimension Materials 233
7.5 Fabrication of Thin Film Thermoelectric Materials 235
7.5.1 Chemical Vapor Deposition 235
7.5.2 Electrodeposition 236
7.5.3 Physical Vapor Deposition 237
7.5.4 Sputtering 238
7.6 Application of Thermoelectric Effect in Sensors: Thermal Sensors 239
7.6.1 Performance Parameters 239
7.6.2 Radiation Detectors 240
7.6.3 Chemical Sensor 241
7.6.4 Flow Sensors 242
7.7 Vacuum Sensors 247
7.8 Conclusion 248
References 249
Chapter 8: Electroluminescent Thin Film Phosphors 253
8.1 Introduction 254
8.2 Characteristics of Phosphors 256
8.2.1 Luminous Efficacy 256
8.2.2 Quantum Efficiency 257
8.2.3 Color Rendering Index 258
8.2.4 Degradation Characteristics 259
8.3 Preparation of Thin Film Phosphors 259
8.3.1 Pulsed Laser Deposition Technique 260
8.3.1.1 Description of PLD Technique 260
8.3.2 Metal Organic Chemical Vapour Deposition (MOCVD) 261
8.3.3 Sputter Deposition 263
8.3.4 Spray Pyrolysis 264
8.3.5 Sol-Gel Technology 266
8.4 Electroluminescent Phosphors 268
8.4.1 Red Emitting Electroluminescent Phosphor 270
8.4.2 Blue Emitting Electroluminescent Phosphor 272
8.4.3 Green Emitting Electroluminescent Phosphor 275
8.5 Conclusions 277
References 277
Chapter 9: Thin Films for Energy-Efficient Mechanical Tools 280
9.1 Introduction: Demands from Machining Industry 280
9.2 Hardening of Solid 281
9.3 Anion Substitution of Transition Metal Nitrides to Change the Chemical Bonds 282
9.4 Composition Control by Stress from Substrates in Epitaxially Grown Cr(N,O) Thin Films 285
9.5 Hardening in (Cr, Al) (N,O) Thin Films by Introducing Inclusions 288
9.6 Hardening by Cr-Si-N-O Thin Films by Controlling the Grain Size 290
9.7 Conclusion 293
References 294
Index 295