Understand a groundbreaking new energy technology

Solar energy is one of the most important paths to a sustainable future. In recent years, extensive research and development has begun to produce wearable solar cells, whose novel planar and fiber format gives them enormous flexibility and a wide range of potential uses. The possibility of a solar energy source that can be fitted to the human body promises to become an extraordinary tool for meeting various kinds of personal energy needs.

Wearable Solar Cells: Mechanisms, Materials, and Devices serves as a comprehensive introduction to this cutting-edge technology and its applications. Recent research pointing towards fiber-format solar cells as a bold new frontier is summarized and explored. The result is an essential resource for both experienced researchers and newcomers to the field.

Wearable Solar Cells readers will also find:Close coverage of integrated energy harvesting and storage devicesDetailed discussion of dye-sensitized solar cells, polymer solar cells, perovskite solar cells, and moreAn authorial team with decades of combined research experience

Wearable Solar Cells is ideal for materials scientists, polymer chemists, electrical engineers, solid-state physicists, and advanced students interested in these and related topics.

Hao Sun, PhD, is Associate Professor in the Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Zhangjiang Institute for Advanced Study, and Key Laboratory of Green and High-End Utilization of Salt Lake Resources (Chinese Academy of Sciences) at Shanghai Jiao Tong University, China. His research centers on fiber electronics and energy storage devices.

Zhibin Yang, PhD, is Associate Professor in the School of Chemistry and Chemical Engineering at Shanghai Jiao Tong University, China. His current research focuses on perovskite solar cells and wearable electronics.

Longbin Qiu, PhD, is Assistant Professor in the Department of Mechanical and Energy Engineering at Southern University of Science and Technology, China. His current interests focus on the scalable and stable perovskite solar modules, as well as flexible and wearable electronics.

Huisheng Peng, PhD, is Professor in the Department of Macromolecular Science and Laboratory of Advanced Materials at Fudan University, China. His research focuses on fiber electronics.

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