6.2 Homo- and Heterojunction III-V Solar Cells 115
6.2.1 GaAs Solar Cells 117
6.2.2 InP Solar Cells 120
6.2.3 InGaAsP 121
6.2.4 GaN 121
6.3 Multijunction Solar Cells 122
6.3.1 Monolithic Multijunction Solar Cells 123
6.3.2 Mechanically Stacked Multijunction Solar Cells 129
6.4 Applications 131
6.4.1 III-V Space Photovoltaic Systems 131
6.4.2 III-V Concentrator Photovoltaic Systems 132
6.5 Conclusion 134
References 134
7 Chalcogenide Thin-Film Solar Cells 145 M. Paire, S. Delbos, J. Vidal, N. Naghavi and J.F. Guillemoles
7.1 Introduction 145
7.2 CIGS 148
7.2.1 Device Fabrication 148
7.2.2 Material Properties 162
7.2.3 Device Properties 171
7.2.4 Outlook 181
7.3 Kesterites 185
7.3.1 Advantages of CZTS 185
7.3.2 Crystallographic and Optoelectronic Properties 187
7.3.3 Synthesis Strategies 190
Acknowledgements 196
References 196
8 Printed Organic Solar Cells 217 Claudia Hoth, Andrea Seemann, Roland Steim, Tayebeh Ameri, Hamed Azimi and Christoph J. Brabec
8.1 Introduction 217
8.2 Materials and Morphology 218
8.2.1 Organic Semiconductors 219
8.2.2 Control of Morphology in oBHJ Solar Cells 224
8.2.3 Monitoring Morphology 233
8.2.4 Numerical Simulations of Morphology 235
8.2.5 Alternative Approaches to Control the Morphology 235
8.3 Interfaces in Organic Photovoltaics 237
8.3.1 Origin of Voc 237
8.3.2 Determination of Polarity-Inverted and Noninverted Structure 238
8.3.3 Optical Spacer 239
8.3.4 Protection Layer between the Electrode and the Polymer 240
8.3.5 Selective Contact 240
8.3.6 Interface Material Review for OPV Cells 240
8.4 Tandem Technology 243
8.4.1 Theoretical Considerations 243
8.4.2 Review of Experimental Results 248
8.4.3 Design Rules for Donors in Bulk-Heterojunction Tandem Solar Cells 255
8.5 Electrode Requirements for Organic Solar Cells 257
8.5.1 Materials for Transparent Electrodes 258
8.5.2 Materials for Nontransparent Electrodes 263
8.6 Production of Organic Solar Cells 265
8.7 Summary and Outlook 273
References 273
9 Third-Generation Solar Cells 283 Gavin Conibeer
9.1 Introduction 283
9.2 Multiple-Energy-Level Approaches 285
9.2.1 Tandem Cells 285
9.2.2 Multiple-Exciton Generation (MEG) 291
9.2.3 Intermediate-Band Solar Cells (IBSC) 293
9.3 Modification of the Solar Spectrum 294
9.3.1 Downconversion, QE > 1 294
9.3.2 Upconversion of Below-Bandgap Photons 297
9.4 Thermal Approaches 302
9.4.1 Thermophotovoltaics (TPV) 303
9.4.2 Thermophotonics 303
9.4.3 Hot-Carrier Cells 303
9.5 Other Approaches 308
9.5.1 Nonreciprocal Devices 308
9.5.2 Quantum Antennae – Light as a Wave 308
9.6 Conclusions 309
Acknowledgements 309
References 310
Concluding Remarks 315 Gavin Conibeer and Arthur Willoughby
Index 319
This book presents a comparison of solar cell materials, including both new materials based on organics, nanostructures and novel inorganics and developments in more traditional photovoltaic materials.
It surveys the materials and materials trends in the field including third generation solar cells (multiple energy level cells, thermal approaches and the modification of the solar spectrum) with an eye firmly on low costs, energy efficiency and the use of abundant non-toxic materials.