Wearable Solar Cells

About the Authors ix Preface xi 1 Introduction 1 1.1 Development of Wearable Solar Cells 1 1.2 Characteristics of Fiber-Shaped Solar Cells 2 1.3 Functionalization and Integration 2 1.4 Applications of Wearable Solar Cells 3 References 4 2 Working Mechanisms of Solar Cells 7 2.1 Introduction 7 2.2 Working Mechanism and Efficiency Limitation for Solar Cells 8 2.2.1 Detailed Balance Limitation 12 2.2.2 Drift-Diffusion Model 14 2.2.3 Equivalent Circuit Model 15 2.3 Working Mechanism of Dye-Sensitized Solar Cells 16 2.4 Working Mechanism of Polymer Solar Cells 18 2.5 Working Mechanism of Perovskite Solar Cells 19 2.6 Comparison of Solar Cells for Flexible and Wearable Application 22 2.7 Conclusions 24 References 25 3 Flexible Film Solar Cells 31 3.1 Overview of Flexible Film Solar Cells 31 3.2 Flexible Transparent Conductive Electrodes 31 3.2.1 Metal Oxides 32 3.2.2 Conductive Polymers 33 3.2.3 Carbon Nanomaterials 34 3.2.3.1 Graphene 34 3.2.3.2 Carbon Nanotube 37 3.3 Fabrication Techniques of Flexible Film Solar Cells 39 3.3.1 Spin Coating 40 3.3.2 Blade Coating 41 3.3.3 Slot-Die Coating 43 3.3.4 Screen Printing 43 3.3.5 Roll-to-Roll System 45 3.4 Flexible Organic Solar Cells 46 3.5 Flexible Dye-Sensitized Solar Cells 50 3.6 Flexible Perovskite Solar Cells 53 3.7 Summary and Perspective 56 References 58 4 Flexible Fiber Electrodes 67 4.1 Introduction 67 4.2 Metal Wires 68 4.2.1 Titanium 68 4.2.2 Stainless Steel 70 4.2.3 Other Metals 70 4.3 Polymer Fibers 71 4.4 Carbon-Based Fiber 73 4.4.1 Carbon Fiber 73 4.4.2 Carbon Nanotube Fiber 75 4.4.3 Graphene Fiber 83 4.5 Functional Fibers 87 4.6 Summary and Perspectives 88 References 89 5 Fiber-Shaped Dye-Sensitized Solar Cells 95 5.1 Introduction 95 5.2 Twisting Structure 97 5.2.1 Photoanode 97 5.2.2 Counter Electrode 101 5.2.3 Electrolyte 104 5.3 Coaxial Structure 105 5.4 Functionalization and Integration 106 5.4.1 Functional Fiber-Shaped DSSCs 107 5.4.2 Integrated Fiber-Shaped DSSCs 109 5.5 Summary and Prospects 114 References 115 6 Fiber Polymer Solar Cells 121 6.1 Overview of Polymer Solar Cells 121 6.2 Overview of Fiber-Shaped Polymer Solar Cells 123 6.2.1 Fiber-Shaped Polymer Solar Cells with Twisting Structure 123 6.2.2 Fiber Polymer Solar Cells with a Coaxial Structure 127 6.3 Polymer Solar Cell Textiles 129 6.4 Summary and Perspective 130 References 132 7 Fiber Perovskite Solar Cells 135 7.1 Introduction 135 7.2 Perovskite Photoactive Materials and Solar Cells 136 7.3 Deposition of Perovskite Layer on Fiber/Wire Surfaces 139 7.3.1 Perovskite Formation Strategies 139 7.3.2 Dip-Coating Process 142 7.3.3 Cathodic Electrodeposition 145 7.3.4 Thermal Evaporation 145 7.3.5 Electrode-Spinning 146 7.4 Charge Transport Layers for Fiber Perovskite Solar Cells 147 7.5 Electrode Materials for Fiber Perovskite Solar Cells 149 7.6 Stretchable and Wearable Fiber Perovskite Solar Cells 149 7.7 Summary and Perspectives: Challenges for Fiber Perovskite Solar Cells 151 References 153 8 Fiber-Shaped Integrated Device 159 8.1 Overview of Integrated Device Based on Solar Cells 159 8.2 Overview of Fiber-Integrated Device Based on Solar Cells 161 8.2.1 Fiber-Shaped Integrated Device Based on Solar Cells and Supercapacitors 161 8.2.2 Fiber-Shaped Integrated Device Based on Solar Cell and Lithium-Ion Battery 164 8.2.3 Fiber Integrated Device Based on Nanogenerator and Solar Cell 165 8.2.4 Fiber-Based Integrated Textiles 167 8.3 Summary and Perspective 171 References 172 9 Novel Interfaces in Wearable Solar Cells 175 9.1 Introduction 175 9.2 Interfacial Charge Transfer 176 9.2.1 Charge Transfer Within Fiber Electrode 176 9.2.2 Charge Transport at the Active Material/Fiber Electrode Interface 178 9.3 Charge Separation 182 9.3.1 Charges Separation Between Photoactive/Electron Transport Materials 182 9.3.2 Charge Separation Based on an Intermediate Layer 185 9.4 Interface and Device Performances 186 9.4.1 Interfaces in Different Device Structures 186 9.4.2 Interfacial Stability and the Influence on Solar Cell Performance 189 9.5 Interface of Functional Wearable Solar Cells 190 9.6 Interfaces for Encapsulation 193 9.6.1 Polymer Tubes 193 9.6.2 Gel Electrolytes 193 9.6.3 Polymer Coatings 196 9.7 Summary and Outlook 196 References 197 10 Textile Solar Cells 201 10.1 Introduction 201 10.2 Textile Solar Cell Structures 202 10.2.1 Incorporation of Planar Solar Cells on Textile Substrate 203 10.2.2 Strip-Shaped Solar Cells 206 10.2.3 Textile Electrode 208 10.2.4 Textile Solar Cells Based on Fiber-Shaped Solar Cells 210 10.2.5 Interlaced Fiber Electrodes 211 10.3 Weaving Patterns and Incidence Angle for Textile Solar Cells 213 10.4 Mechanics and Breathability of Textile Solar Cells 216 10.5 Encapsulation Structure and Materials for Textile Solar Cells 218 10.6 Application of Textile Solar Cells 220 10.7 Summary and Perspectives 222 References 222 11 Summary and Outlook 227 11.1 Introduction 227 11.2 Development of Planar Solar Cells for Wearable Applications 227 11.3 Performance Improvement of Fiber and Textile Solar Cells 229 11.4 Continuous Production of Fiber and Textile Solar Cells 230 11.5 Potential Applications of Fiber and Textile Solar Cells 231 References 232 Index 235