Chemically Deposited Nanocrystalline Metal Oxide Thin Films : Synthesis, Characterizations, and Applications

Foreword Preface Contents About the Editors and Contributors About the Editors Contributors Chapter 1: Progress in Solution-Processed Mixed Oxides 1.1 Introduction 1.2 Solution-Processed Methods for Synthesis of Mixed Oxide 1.2.1 Electrodeposition 1.2.2 Successive Ionic Layer Adsorption and Reaction (SILAR) 1.2.3 Precipitation Method 1.2.4 Sol-Gel 1.2.5 Chemical Bath Deposition (CBD) 1.3 Conclusions References Chapter 2: Properties and Applications of the Electrochemically Synthesized Metal Oxide Thin Films 2.1 Introduction 2.2 Electrochemical Synthesis 2.3 Electrodeposition of Metal Oxide as Thin Films 2.3.1 Zinc Oxide (ZnO) 2.3.1.1 Applications of ZnO 2.3.2 Copper Oxide (Cu2O) 2.3.2.1 Applications of CuO 2.3.3 Nickel Oxide (NiO) 2.3.3.1 Applications of NiO 2.4 Conclusion References Chapter 3: Structural and Electronic Properties of Various Useful Metal Oxides 3.1 Introduction 3.2 Structural and Electronic Properties of Various Metal Oxides 3.2.1 Titanium Dioxide (TiO2): Local-Density Approximation (LDA) Approach 3.2.2 Structural, Cohesive, and Elastic Properties 3.2.3 Electronic Structure 3.3 Anatase TiO2 Nanocrystals 3.3.1 Electronic Properties of Reduced TiO2 Nanocrystals and Stability of Defects 3.4 TiO2 Nanocluster and Dye–Nanocluster Systems: Photovoltaic or Photocatalytic Applications 3.4.1 Methods and Materials 3.4.2 Structural and Electronic Properties of TiO2 Nanocluster and Dye–Nanocluster Systems 3.5 Photoexcited TiO2 Nanoparticles 3.5.1 Structural Properties 3.5.2 Electronic Properties 3.6 Indium Oxide (In2O3) 3.6.1 Structural and Electronic Properties 3.7 Tin(IV) Oxide (SnO2) 3.7.1 Structural and Electronic Properties 3.8 Zinc Oxide (ZnO) 3.8.1 Structural and Electronic Properties 3.9 Copper (I) Oxide (Cu2O), Copper (II) Oxide (CuO), and Copper Dioxide (CuO2) Nanoclusters 3.9.1 Structural and Electronic Properties 3.10 Conclusion References Chapter 4: Properties of Metal Oxides: Insights from First Principles Calculations 4.1 Introduction 4.2 An Example System: BaTiO3 4.3 Summary References Chapter 5: Recent Progress in Metal Oxide for Photovoltaic Application 5.1 Introduction 5.2 Solar Cells for Photovoltaic Applications 5.3 Solar Cell Output Parameters 5.3.1 Short-Circuit Current (Isc) 5.3.2 Open-Circuit Voltage (Voc) 5.3.3 Fill Factor (FF) 5.3.4 Solar Cell Efficiency 5.4 Oxides 5.5 Methods of Synthesizing Metal Oxides for Photovoltaic Application 5.5.1 Hydrothermal/Solvothermal Approach 5.5.2 Thermal Evaporation 5.5.3 Sputtering Deposition 5.5.4 Coprecipitation 5.5.5 Physical Vapor Deposition 5.5.6 Chemical Vapor Deposition 5.5.7 Sol-Gel Approach 5.6 Organic Metal Oxide for Photovoltaic Application 5.6.1 Generation of Exciton in Metal Oxides for Photovoltaic Application 5.6.2 Exciton Diffusion and Dissociation in Metal Oxides 5.6.3 Carrier Transport in Metal Oxide Semiconductors 5.6.4 Extraction of Charges at the Electrodes 5.7 Inorganic Metal Oxide for Photovoltaic Applications 5.7.1 Contributions of Various Inorganic Metal Oxides for the Development of Photovoltaic Cells 5.7.2 Efficiency of Inorganic Photovoltaic Solar Cells Made from Metal Oxides 5.7.3 Hybrid Metal Oxides as Active Materials for Photovoltaic Application 5.7.3.1 Hybrid Perovskite Solar Cells 5.7.3.2 Dye-Sensitized Solar Cells (DSSCs) 5.8 Active Metal Oxide Roles in Photovoltaic Cells 5.8.1 Transparent Electrodes 5.8.2 Charge-Blocking Layers 5.8.3 Charge Collectors 5.8.4 Optical Spacers 5.8.5 Intermediate Layers in Tandem Cells 5.8.6 Stability Enhancers 5.9 Review of Some Metal Oxide Materials Used for Photovoltaic Application 5.10 Conclusion References Chapter 6: Structural and Electronic Properties of Metal Oxides and Their Applications in Solar Cells 6.1 General Introduction 6.2 Structural Properties of Metal Oxides 6.3 Electronic Properties of Metal Oxides 6.4 Application of Some Transition Metal Oxides in Solar Cells 6.4.1 Titanium Dioxide, TiO2 6.4.2 Nickel Oxide, NiO 6.4.3 Manganese Oxide, MnO2 6.4.4 Cerium Oxide, CeO2 6.4.5 Cobalt Oxide, CoO 6.4.6 Molybdenum Oxide, MoO3 6.5 Charge Transport Mechanism in Metal Oxide/Silicon Solar Cells 6.6 Methods of Improving the Efficacy of Transition Metal Oxides 6.6.1 Addition of Dopant 6.6.2 Formation of Composites 6.6.3 Heat/Plasma Treatment 6.6.4 Electroplating 6.7 Conclusion References Chapter 7: Optically Active Metal Oxides for Photovoltaic Applications 7.1 Introduction 7.2 Structure of Thin-Film Solar Cells 7.2.1 Ideal Material Properties Requirement in Thin-Film Solar Cells 7.3 Metal Oxides in Solar Cells 7.4 Application of Metal Oxides in Thin-Film Solar Cells 7.4.1 Metal Oxides as Back Contact and Intermediate Barrier Layers in Thin-Film Solar Cells 7.4.2 Metal Oxides as Absorber Layers in Thin-Film Solar Cells 7.4.3 Metal Oxides as Buffer Layers in Thin-Film Solar Cells 7.4.4 Metal Oxides as TCO Layers in Thin-Film Solar Cells 7.5 Techniques for the Synthesis of Metal Oxides in Thin-Film Solar Cells 7.6 Challenges and Future Scope References Chapter 8: Metal Oxides for Perovskite Solar Cells 8.1 Introduction 8.2 Perovskite Solar Cells 8.2.1 Working Principle 8.2.2 Bandgap Tuning of Perovskite Materials 8.2.2.1 Architecture of Perovskite Solar Cells 8.3 Metal Oxides 8.3.1 ETL 8.3.2 TiO2 8.3.3 SnO2 8.3.4 WO3 8.3.5 ZnO 8.3.6 Nb2O5 8.3.7 HTL 8.3.8 NiOx 8.3.9 CuOx 8.3.10 Ternary Oxides 8.3.11 Issues with Metal Oxides 8.4 Conclusions References Chapter 9: Doped Metal Oxide Thin Films for Dye-Sensitized Solar Cell and Other Non-Dye-Loaded Photoelectrochemical (PEC) Solar Cell Applications 9.1 Introduction 9.2 Using Doping as an Effective Method to Engineer Key Properties of ZnO for Enhanced Energy Harvesting 9.3 Impacts of Al Impurities on Zinc Oxide Properties 9.3.1 Structural Studies 9.3.2 Optical Studies 9.3.3 Morphological Studies 9.4 The Impact of Al-Doped ZnO (AZO) Electrodes on Dye-Sensitize Solar Cell (DSSC) Performance 9.5 Effects of Indium Dopant on ZnO Properties 9.5.1 Film Thickness Studies 9.5.2 Structural Studies 9.5.3 Optical Studies 9.5.4 Morphological Studies 9.5.5 Surface Wettability Studies 9.6 The Impact of In-Doped ZnO (IZO) Electrodes on PEC Solar Cell Performance 9.7 Conclusions References Chapter 10: Doped Metal Oxide Thin Films for Enhanced Solar Energy Applications 10.1 Introduction 10.2 History of Photovoltaics 10.3 Photovoltaic Technology 10.3.1 Working Principle of a Conventional Silicon Photovoltaic Cell 10.3.2 Photovoltaic Cell Performance Characterization 10.3.3 Solar Cells 10.3.3.1 Short-Circuit Current (Isc) 10.3.3.2 Open-Circuit Voltage (Voc) 10.3.3.3 Fill Factor (FF) 10.3.3.4 Conversion Efficiency 10.4 Thin-Film Technology 10.4.1 Doping of Thin Films 10.4.2 Doped Metal Oxide Solar Cell 10.4.2.1 Cobalt Oxide (Co3O4) 10.4.2.2 Titanium Dioxide (TiO2) 10.4.2.3 Copper Oxide (Cu2O or CuO) 10.4.2.4 Ternary Materials 10.5 Conclusion References Chapter 11: Mixed Transition Metal Oxides for Photoelectrochemical Hydrogen Production 11.1 Introduction 11.2 Basic Principles of PEC Water Splitting 11.3 Factors Affecting the Water Splitting Performance 11.3.1 Bandgap of Photoelectrode Materials 11.3.2 Particle Size of Photoelectrode Materials 11.3.3 Degree of Crystallinity 11.3.4 Dimensions and Surface Areas of Electrode Materials 11.3.5 Stability of Photoelectrodes 11.3.6 Light Source 11.3.7 pH of the Electrolyte 11.4 Transition Metal Oxides 11.4.1 Classification of Transition Metal Oxides 11.4.2 Mixed Transition Metal Oxides 11.4.3 Mixed Transition Metal Oxides for Hydrogen Evolution Reaction 11.4.4 Mixed Transition Metal Oxides for Oxygen Evolution Reaction 11.5 Design, Synthesis, and Characterization of Mixed Transition Metal Oxides 11.6 Concluding Remarks References Chapter 12: Plasmonic Metal Nanoparticles Decorated ZnO Nanostructures for Photoelectrochemical (PEC) Applications 12.1 Introduction 12.2 Versatility of ZnO 12.2.1 Phenomenal Crystal Structure of ZnO 12.2.2 Suitability of ZnO for PEC 12.2.3 Morphological Variation of ZnO and Their PEC Performance 12.2.3.1 Enhanced Light Harvesting 12.2.3.2 Localized Surface Plasmon Resonance (LSPR) 12.2.3.3 Charge Transport and Separation at Interfaces Interfaces Inside Photoelectrodes Plasmonic Metal Nanoparticle/ZnO/Semiconductor Photoelectrodes and Electrolytes Interfaces 12.3 Anti-Photocorrosion 12.4 Decoration Vs. Doping 12.5 Outlook and Frontiers References Chapter 13: Oxygen-Deficient Metal Oxide Nanostructures for Photocatalytic Activities 13.1 Introduction 13.2 Methods for Introducing Oxygen Vacancies in Metal Oxide Nanostructures 13.2.1 Doping of Elements 13.2.2 Chemical Reduction/Oxidation 13.2.3 Electrochemical Reduction 13.2.4 Metal Reduction 13.2.5 Hydrogenation of the Metal Oxide 13.2.6 Annealing in Oxygen-Deficient Environment 13.2.7 High-Energy Particle Bombardment 13.3 Spectroscopic Studies for the Evaluation of Charge Carrier Dynamics 13.3.1 Time-Resolved Transient Absorption (TA) Spectroscopy 13.3.2 Time-Resolved Fluorescence Spectroscopy (TRFS) 13.3.3 Soft and Hard X-Ray Spectroscopy 13.4 Photocatalytic Applications of Oxygen-Deficient Metal Oxide Thin Films 13.4.1 Photocatalytic Water Splitting 13.4.2 Photoreduction of Carbon Dioxide (CO2) 13.4.3 Photodegradation of Organic Pollutant 13.5 Conclusions and Future Outlook References Chapter 14: Oxygen-Deficient Iron Oxide Nanostructures for Photocatalytic Activities 14.1 Introduction 14.2 Iron Oxide Nanostructures as Photocatalysts 14.3 Methods of Preparation of Oxygen-Deficient Iron Oxide Nanostructures 14.3.1 Solvothermal/Hydrothermal Synthesis 14.3.2 Chemical Reductants 14.3.3 Calcination: Vacuum Activation 14.3.4 Sol-Gel Processing 14.3.5 Chemical Precipitation Method 14.3.6 Anodization Method 14.3.7 Vapour Deposition Method 14.3.8 Spray Pyrolysis Method 14.4 Photocatalysis 14.4.1 Photocatalytic Water Splitting for Hydrogen Generation 14.4.2 Photocatalytic Degradation 14.4.3 CO2 Reduction 14.5 Challenges and Opportunities References Chapter 15: Properties of Titanium Dioxide-Based Nanostructures on Transparent Glass Substrates for Water Splitting and Photocatalytic Application 15.1 Introduction 15.2 Methods of Synthesis for the Development of Titanium Dioxide Nanostructures on Conductive Transparent Substrates 15.2.1 Hydrothermal Method 15.2.2 Precursors 15.3 Development, Formation Mechanism and Physical Properties of Titanium Dioxide-Based Nanostructures Developed on Transparent Glass Substrates by Hydrothermal Method 15.3.1 Synthesis 15.3.2 Effect of Hydrothermal Growth Time on the Orientation and Size of Nanostructures with Respect to Substrate 15.4 Structural Properties of a Single Rutile-Phase TiO2 Rod 15.5 Conclusion References Chapter 16: Mixed Transition Metal Oxides for Energy Applications 16.1 Introduction 16.2 Fundamentals of Energy Storage Devices 16.2.1 Supercapacitor as Energy Storage Device 16.2.2 Basic Structure of Supercapacitors and Physical Phenomenon 16.2.3 Types of Supercapacitors 16.3 Lithium-Ion Battery (LIB) as Energy Storage Device 16.3.1 Basic Structure of LIB and Physical Phenomenon 16.4 Requirements of Good Energy Storage Material 16.4.1 Features of MTMO Influencing Electrochemical Performance 16.4.2 Specific Features of MTMOs for Efficient LIB Cell 16.5 Synthesis Strategy for MTMO by Chemical Methods 16.5.1 Chemical Bath Deposition (CBD) Method 16.5.2 Successive Ionic Layer Adsorption and Reaction (SILAR) Method 16.5.3 Hydrothermal Method 16.5.4 Spin Coating Method 16.5.5 Sol-Gel Method 16.5.6 Summary of Synthesis Approaches 16.6 MTMO-Based Energy Storage Materials 16.7 Supercapacitor Electrode Materials 16.7.1 MTMO-Based Supercapacitors 16.8 MTMO-Based Anode Materials for LIB 16.9 Conclusions References Chapter 17: Nanosheet-Derived Porous Materials and Coatings for Energy Storage Applications 17.1 Introduction 17.2 Nanosheets 17.2.1 Synthetic Approaches for 2D Inorganic Nanosheets 17.2.1.1 Intercalation 17.2.1.2 Protonation 17.2.1.3 Ion Exchange 17.2.1.4 Successive Aqueous Sonication or Exfoliation 17.3 Nanosheet-Based Hybrids 17.3.1 Properties of Nanosheets and Nanosheet-Based Hybrids 17.3.1.1 Anisotropic Morphology and Flexibility 17.3.1.2 Extremely Small Thickness 17.3.1.3 Photoinduced Surface Functionality 17.3.1.4 Flexibility of Composition Control 17.3.1.5 Surface Charge 17.3.1.6 Expanded Surface Area 17.4 Synthetic Strategies for 2D Nanosheet-Based Hybrids 17.4.1 Ion Exchange or Intercalation 17.4.2 Anchored Assembly 17.4.3 Layer-by-Layer (LBL) Film Deposition 17.4.4 Exfoliation Reassembling (ER) 17.5 Application to Supercapacitors 17.5.1 Requirements of Nanosheets as Electrode Materials 17.5.2 Recent Work on Nanosheet-Based Materials for Supercapacitors 17.6 Application to Batteries 17.6.1 Requirements of Nanosheets as Electrode Materials 17.6.2 Working of Rechargeable Battery 17.6.3 Recent Work on Nanosheet-Based Materials for Batteries 17.7 Summary References Chapter 18: Role of Carbon Derivatives in Enhancing Metal Oxide Performances as Electrodes for Energy Storage Devices 18.1 Introduction 18.2 Energy Storage Devices 18.2.1 Battery 18.2.1.1 Battery Electrode Materials 18.2.2 Supercapacitor 18.2.2.1 Types of Supercapacitors 18.3 Metal Oxides 18.3.1 Cobalt Oxide (Co3O4) 18.3.2 Manganese Oxide (MnO2) 18.3.3 Nickel Oxide (NiO) 18.3.4 Copper Oxide (CuO) 18.3.5 Zinc Oxide (ZnO) 18.4 Carbon Derivatives 18.4.1 Graphene Oxide (GO) 18.4.2 Reduced Graphene Oxide (rGO) 18.4.3 Carbon Nanotubes (CNTs) 18.4.4 Activated Carbon (AC) 18.4.5 Carbon-Derived Carbon (CDC) 18.4.6 Carbon Aerogels (CAs) 18.5 Exceptional Selected Results 18.6 Conclusion References Chapter 19: Hydrothermal Synthesis of Metal Oxide Composite Cathode Materials for High Energy Application 19.1 Introduction 19.2 Hydrothermal Synthesis (HS) Apparatus 19.3 Hydrothermal Synthesis (HS) of Metal Oxide Composite 19.3.1 Batch Hydrothermal Reaction System 19.3.2 Flow Hydrothermal Reaction System 19.4 Metal Oxide Composite Cathode Materials for High Energy Density Storage 19.5 Solvents Under Hydrothermal Synthesis (HS) 19.6 Hydrothermal Synthesis of NaFe2O3-GO 19.6.1 Experiment 19.6.2 Characterization and Testing of NaFe2O3-GO 19.7 The Future of the Hydrothermal Synthesis Method 19.8 Conclusions References Chapter 20: Metal Oxide Composite Cathode Material for High Energy Density Batteries 20.1 Introduction 20.2 Performance Indicator of Secondary Batteries 20.3 Storage Mechanisms in Li-Ion Batteries 20.4 Crystal Structures of Cathode Materials 20.5 Composite Materials as Cathode for Li-Ion Batteries 20.5.1 Layered LiCoxNi1−xO2 20.5.2 Layered LiNixMn1−xO2 20.5.3 Spinel LiNixMn2−xO4 20.5.4 Layered LiNixCoyMn1−x−yO2 20.5.5 Conversion-Type Cathode for Secondary Batteries 20.6 From Monovalent to Multivalent Secondary Batteries 20.7 Challenges 20.8 Conclusion and Outlooks References Chapter 21: Chemically Processed Transition Metal Oxides for Post-Lithium-Ion Battery Applications 21.1 Introduction 21.2 Transition Metal Oxides for Non-aqueous Sodium/Sodium-Ion Batteries 21.2.1 Titanium Oxide (TiO2) 21.2.2 Vanadium Oxide (V2O5) 21.2.3 Chromium Oxide (Cr2O7) 21.2.4 Manganese Oxide (MnO) 21.2.5 Iron Oxide (Fe2O3) 21.2.6 Cobalt Oxide (Co3O4) 21.2.7 Nickel Oxide (NiO) 21.2.8 Cupric Oxide (CuO) 21.2.9 Molybdenum Oxide (MoO3) 21.3 Transition Metal Oxides for Non-aqueous Potassium/Potassium-Ion Batteries 21.3.1 Titanium Oxide (TiO2) 21.3.2 Cobalt Oxide and Iron Oxide (Co3O4-Fe2O3) 21.3.3 Cupric Oxide (CuO) 21.3.4 Molybdenum Oxide (MoO2) 21.4 Transition Metal Oxides for Other Non-aqueous Multivalent Ion Batteries 21.4.1 TMOs in Magnesium Metal Batteries 21.4.2 TMOs in Calcium Metal Batteries 21.4.3 TMOs in Zinc Metal Batteries 21.4.4 TMOs in Aluminum Metal Batteries 21.5 Summary and Perspectives References Chapter 22: Nanostructured Metal Oxide-Based Electrode Materials for Ultracapacitors 22.1 Introduction 22.2 Components of Supercapacitor 22.2.1 Electrode 22.2.2 Electrolyte 22.2.3 Current Collectors 22.2.4 Separator 22.2.5 Sealant 22.3 Fundamentals of Supercapacitance 22.3.1 Electric Double-Layer Capacitors (EDLCs) 22.3.2 Redox Processes 22.3.3 Assessing the Electrochemical Mechanism of a Working (Active) Electrode 22.4 Electrode Preparation Techniques 22.4.1 Preparation of MOx Nanostructures Using Liquid-Based Techniques 22.4.1.1 Hydrothermal 22.4.1.2 Advantages of Hydrothermal Synthesis Over Other Methods 22.4.1.3 Electrochemical Deposition 22.4.1.4 Advantages of Electrochemical Deposition 22.4.1.5 Aqueous Solution Deposition 22.4.1.6 Advantages of Aqueous Solution-Based Deposition 22.4.2 Nanoporous MOx from Metal-Organic Frameworks (MOFs) 22.5 Performances of Metal Oxide Supercapacitor Electrode 22.6 Applications of Supercapacitor 22.6.1 Electric Vehicle (EV) 22.6.2 Electric Rail Transit System 22.6.3 Mobile Device 22.6.4 Memory Device 22.6.5 Wearable Electronic Device 22.6.6 Micro-Grid 22.6.7 Chemi-Resistive pH Sensing 22.7 Outlook and Summary of Nanoporous Metal Oxide-Based Supercapacitors References Chapter 23: Nanoporous Metal Oxides for Supercapacitor Applications 23.1 Introduction to Nanoporous Metal Oxides 23.2 Synthetic Approach for Nanoporous Metal Oxides 23.2.1 Template Synthesis Methods 23.2.1.1 Hard Template Method 23.2.1.2 Soft Template Method 23.2.2 Chemical Methods for Synthesis of Nanoporous Metal Oxides 23.2.2.1 Hydrothermal (Solvothermal) Method 23.2.2.2 The Chemical Bath Deposition Method 23.2.2.3 Electrochemical Deposition Method 23.2.2.4 Sol Gel Method 23.3 A Newer Approach for Nanoporous Metal Oxides for Supercapacitor Application 23.3.1 Advantages of Chemical Methods 23.3.2 Toward the Commercialization of Nanoporous Metal Oxides References Chapter 24: Nanoporous Transition Metal Oxide-Based Electrodes for Supercapacitor Application 24.1 Introduction 24.2 Fundamentals of Supercapacitor 24.2.1 Electrochemical Double-Layer Capacitive Materials 24.2.2 Pseudocapacitive Materials 24.2.3 Intrinsic or Surface Redox Pseudocapacitive Materials 24.2.4 Intercalation Pseudocapacitive Materials 24.2.5 Extrinsic Pseudocapacitive Materials 24.2.6 Hybrid Supercapacitive Materials 24.3 Nanoporous Transition Metal Oxides: Pseudocapacitive Electrodes 24.4 Nanoporous Transition Metal Oxide-Based Electrode Materials for Supercapacitor 24.4.1 Ruthenium Oxide 24.4.2 Manganese Oxide 24.4.3 Nickel Oxide 24.4.4 Copper Oxide 24.4.5 Cobalt Oxide 24.4.6 Vanadium Oxide 24.4.7 Iron Oxide 24.4.8 Bismuth Oxide 24.5 Rare-Earth Metal Oxide 24.6 Summary, Perspective, and Conclusions References Chapter 25: Hybrid Nanocomposite Metal Oxide Materials for Supercapacitor Application 25.1 Introduction 25.2 Types of Hybrid Nanocomposite Metal Oxides 25.2.1 Ruthenium Oxide-Based Nanocomposites 25.2.1.1 Ruthenium Oxide/Reduced Graphene Oxide Hybrid Nanocomposite Materials 25.2.1.2 Ruthenium Oxide/Tin Oxide Hybrid Nanocomposite Materials 25.2.1.3 Ruthenium Oxide/Titanium Dioxide Hybrid Nanocomposite Materials 25.2.2 Manganese Oxide-Based Nanocomposites 25.2.2.1 Manganese Oxide/Reduced Graphene Oxide Hybrid Nanocomposite Materials 25.2.2.2 Manganese Oxide/Tin Oxide Nanocomposite Materials for Supercapacitors 25.2.2.3 Manganese Oxide/Nickel Oxide Nanocomposite Materials for Supercapacitors 25.2.3 Cobalt-Oxide Based Nanocomposites for Supercapacitors 25.2.3.1 Cobalt Oxide/Reduced Graphene Oxide Nanocomposite Materials for Supercapacitors 25.2.3.2 Cobalt Oxide/Manganese Oxide Nanocomposite Materials for Supercapacitors 25.2.3.3 Cobalt Oxide/Copper Oxide Nanocomposite Materials for Supercapacitors 25.2.4 Nickel Oxide-Based Nanocomposites for Supercapacitors 25.2.4.1 Nickel Oxide/Reduced Graphene Oxide Nanocomposite Materials for Supercapacitors 25.2.4.2 Nickel Oxide/Titanium Dioxide Nanocomposite Materials for Supercapacitors 25.2.4.3 Nickel Oxide/Cobalt Oxide Nanocomposite Materials for Supercapacitors 25.3 Conclusion References Chapter 26: Liquid Phase Deposition of Nanostructured Materials for Supercapacitor Applications 26.1 Introduction 26.2 Deposition Method: Liquid Phase Deposition (LPD) 26.3 Materials Deposited by LPD as the Electrode Material for Supercapacitors 26.3.1 Iron Oxide 26.3.2 Copper Oxide 26.3.3 Layered Double Hydroxides (LDHs) 26.4 Conclusions References Chapter 27: Chemically Processed Metal Oxides for Sensing Application: Heterojunction Room Temperature LPG Sensor 27.1 Introduction 27.2 Types of Gas Sensors 27.3 Chemical Methods 27.3.1 Advantages of Chemical Methods 27.4 Experimental Setup: Design and Operation 27.4.1 Device Construction 27.4.2 Device Testing 27.4.3 LPG Testing and Performance 27.4.4 Gas Response: Current-Voltage (I-V) Characteristics 27.4.5 Gas Response vs. Gas Concentration 27.4.6 Gas Response vs. Time 27.4.7 Stability Studies 27.4.8 Gas Selectivity 27.4.9 EIS Studies 27.5 Mechanism of LPG Sensor 27.5.1 Isotype Heterojunction Based 27.5.1.1 n-n Junction 27.5.1.2 p-p Junction 27.5.2 Anisotype Heterostructure Based 27.6 Material Requirements for LPG Sensor 27.6.1 Substrate 27.7 Heterojunction (Both Isotype and Anisotype) Partners 27.7.1 Material Type 27.7.2 Structure and Morphology 27.7.3 Porosity/Surface Area 27.7.4 Energy Band Alignment 27.7.5 Contacts 27.7.5.1 Conductivity 27.7.6 Work Function 27.8 Review of Chemically Deposited Heterojunction: LPG Sensors 27.9 Limitations and Future Prospects 27.10 Summary References Chapter 28: Chemically Synthesized Novel Materials for Gas-Sensing Applications Based on Metal Oxide Nanostructure 28.1 Introduction 28.2 Classification of Gas Sensors 28.3 Gas Sensor Performance 28.4 Mechanism of Gas Sensing 28.5 Growth of Metal Oxide Chemical Sensors 28.6 Some Novel Metal Oxides-Based Gas Sensors 28.6.1 Tin Oxide (SnO2)-Based Gas Sensors 28.6.2 Zinc Oxide-Based Gas Sensor 28.6.3 Other Metal Oxide-Based Gas Sensors 28.7 Conclusion References Chapter 29: Low-Temperature Processed Metal Oxides and Ion-Exchanging Surfaces as pH Sensor 29.1 Introduction 29.2 How Do Electrochemical pH Sensors Work? 29.2.1 Basic Approach to Electrochemical pH Sensing Concept of Electrode Potential 29.2.2 Nernst Relationship and the Nernstian Behavior 29.2.3 Classification of Electrochemical pH Sensors 29.2.4 Metal Oxide Electrode-pH-Sensing Mechanism: How Are Metal Oxides Adapted for Ion Exchange? 29.3 Fabrication of Metal Oxide Electrode for pH Sensors 29.3.1 Electrodeposition 29.3.2 Sputtering 29.3.3 Hydrothermal 29.3.4 Spin Coating 29.3.5 Sol–Gel 29.3.6 Chemical Bath Deposition (CBD) 29.3.7 SILAR 29.4 Measure of pH Performance 29.4.1 Response Time (t90) 29.4.2 Selectivity/Interference Effect 29.4.3 Hysteresis Effect 29.4.4 Drift Effect 29.4.5 Sensitivity/Nernstian Response 29.4.6 Reversibility 29.4.7 Temperature Coefficient of Sensitivity (TCS) 29.5 Overview of Various MOx for pH Sensor Application 29.5.1 Ruthenium Oxide (RuOx) pH Sensors 29.5.2 Iridium Oxide (IrOx) pH Sensors 29.5.3 Tungsten Oxide (WO3) pH Sensors 29.5.4 Titanium Oxide (TiO2) pH Sensor 29.5.5 Tantalum Oxide (Ta2O5) pH Sensors 29.5.6 Zinc Oxide (ZnO) pH Sensor 29.6 Conclusion References Chapter 30: Performance Evaluation of P-Type Semiconducting Metal Oxide-Based Gas Sensors 30.1 Introduction 30.2 Gas-Sensing Mechanism of P-Type SMOs 30.2.1 Electron Interactions 30.2.2 Band Bending 30.2.3 Resistance Modification 30.3 Performance of P-Type SMO Gas Sensors 30.3.1 Cobalt Oxide (Co3O4) 30.3.2 Nickel Oxide (NiO) 30.3.3 Copper Oxide (Cu2O or CuO) 30.3.4 Manganese Oxide (MnO2) 30.4 Types of Gases Detectable by P-Type SMO Gas Sensor 30.4.1 Nitrogen Oxide (NO2) Gas 30.4.2 Hydrogen Sulphide (H2S) Gas 30.4.3 Ammonia (NH3) Gas 30.4.4 Sulphur Oxide (SO2) Gas 30.4.5 Carbon Dioxide (CO2) Gas 30.4.6 Carbon Monoxide (CO) Gas 30.5 Conclusions References Chapter 31: Development of InSb Nanostructures on GaSb Substrate by Metal-Organic Chemical Vapour Deposition: Design Considerations and Characterization 31.1 Introduction and Motivation 31.2 Historical Background of MOCVD Technique 31.3 MOCVD System Design and Working Mechanism 31.4 Conceptualization and Theoretical Background 31.4.1 Lattice Mismatch 31.4.2 Quantum Confinement Effect 31.5 MOCVD Growth Parameters 31.5.1 V/III Ratio 31.5.2 Growth Temperature 31.5.3 Reactor Pressure 31.5.4 Molar Flow Rate and Growth Rate 31.5.5 Substrate Orientation 31.6 Design Considerations for Semiconductor Nanostructures 31.6.1 Influence of Strain on the Electronic Structure of a Quantum Dot 31.6.2 Size and Aspect Ratio Effect on the Optical Properties of a Quantum Dot 31.7 Experimental Technique and Deposition Process 31.8 Results and Discussion 31.8.1 SPM and SEM Analysis 31.8.2 Photoluminescence Spectroscopy Measurements 31.8.3 TEM Analysis 31.8.4 Simulation of the Effect of Spacer Layer Thickness on the Band Edge Emission and Energy Levels of InGaSb/GaSb Quantum Wells 31.8.5 Conclusion References Index This book guides beginners in the areas of thin film preparation, characterization, and device making, while providing insight into these areas for experts. As chemically deposited metal oxides are currently gaining attention in development of devices such as solar cells, supercapacitors, batteries, sensors, etc., the book illustrates how the chemical deposition route is emerging as a relatively inexpensive, simple, and convenient solution for large area deposition. The advancement in the nanostructured materials for the development of devices is fully discussed. Provides detailed and simplified fabrication techniques with images; Includes comprehensive discussion on the structural, optical, morphological, electrical, sensing, and electrochemical properties of the metal oxides; Explains how and where the materials can be used