Solar Cell Device Physics (eBook)

Front Cover 1
Solar Cell Device Physics 4
Copyright Page 5
Contents 8
Preface 12
Acknowledgments 14
List of Symbols 16
List of Abbreviations 28
Chapter 1 Introduction 30
1.1 Photovoltaic Energy Conversion 30
1.2 Solar Cells and Solar Energy Conversion 31
1.3 Solar Cell Applications 36
References 37
Chapter 2 Material Properties and Device Physics Basic to Photovoltaics 38
2.1 Introduction 38
2.2 Material Properties 39
2.2.1 Structure of solids 39
2.2.2 Phonon spectra of solids 42
2.2.3 Electron energy levels in solids 47
2.2.4 Optical phenomena in solids 57
2.2.5 Carrier recombination and trapping 65
2.2.6 Photocarrier generation 74
2.3 Transport 75
2.3.1 Transport processes in bulk solids 75
2.3.2 Transport processes at interfaces 82
2.3.3 Continuity concept 87
2.3.4 Electrostatics 89
2.4 The Mathematical System 89
2.5 Origins of Photovoltaic Action 92
References 93
Chapter 3 Structures, Materials, and Scale 96
3.1 Introduction 96
3.2 Basic Structures for Photovoltaic Action 98
3.2.1 General comments on band diagrams 98
3.2.2 Photovoltaic action arising from built-in electrostatic fields 102
3.2.3 Photovoltaic action arising from diffusion 112
3.2.4 Photovoltaic action arising from effective fields 114
3.2.5 Summary of practical structures 121
3.3 Key Materials 124
3.3.1 Absorber materials 124
3.3.2 Contact materials 131
3.4 Length Scale Effects for Materials and Structures 136
3.4.1 The role of scale in absorption and collection 136
3.4.2 Using the nano-scale to capture lost energy 144
3.4.3 The role of scale in light management 145
References 146
Chapter 4 Homojunction Solar Cells 150
4.1 Introduction 150
4.2 Overview of Homojunction Solar Cell Device Physics 153
4.2.1 Transport 153
4.2.2 The homojunction barrier region 160
4.3 Analysis of Homojunction Device Physics: Numerical Approach 161
4.3.1 Basic p–n homojunction 162
4.3.2 Addition of a front HT-EBL 170
4.3.3 Addition of a front HT-EBL and back ET-HBL 174
4.3.4 Addition of a front high-low junction 178
4.3.5 A p–i–n cell with a front HT-EBL and back ET-HBL 183
4.3.6 A p–i–n cell using a poor & #956
4.4 Analysis of Homojunction Device Physics: Analytical Approach 195
4.4.1 Basic p–n homojunction 196
4.5 Some Homojunction Configurations 208
References 210
Chapter 5 Semiconductor–semiconductor Heterojunction Cells 212
5.1 Introduction 212
5.2 Overview of Heterojunction Solar Cell Device Physics 218
5.2.1 Transport 218
5.2.2 The heterojunction barrier region 222
5.3 Analysis of Heterojunction Device Physics: Numerical Approach 231
5.3.1 Absorption by free electron–hole pair excitations 232
5.3.2 Absorption by exciton generation 266
5.4 Analysis of Heterojunction Device Physics: Analytical Approach 276
5.4.1 Absorption by free electron–hole excitations 276
5.4.2 Absorption by excitons 288
5.5 Some Heterojunction Configurations 288
References 290
Chapter 6 Surface-barrier Solar Cells 292
6.1 Introduction 292
6.2 Overview of Surface-barrier Solar Cell Device Physics 297
6.2.1 Transport 297
6.2.2 The surface-barrier region 300
6.3 Analysis of Surface-barrier Device Physics: Numerical Approach 302
6.4 Analysis of Surface-barrier Device Physics: Analytical Approach 312
6.5 Some Surface-barrier Configurations 320
References 322
Chapter 7 Dye-sensitized Solar Cells 324
7.1 Introduction 324
7.2 Overview of Dye-sensitized Solar Cell Device Physics 326
7.2.1 Transport 326
7.2.2 The dye-sensitized solar cell barrier region 329
7.3 Analysis of DSSC Device Physics: Numerical Approach 330
7.4 Some DSSC Configurations 336
References 337
Appendix A: The Absorption Coefficient 340
Appendix B: Radiative Recombination 342
Appendix C: Shockley-Read-Hall (Gap-state–assisted) Recombination 346
Appendix D: Conduction- and Valence-band Transport 354
Appendix E: The Quasi-neutral-region Assumption and Lifetime Semiconductors 364
Appendix F: Determining p(x) and n(x) for the Space-charge-neutral Regions of a Homojunction 368
Appendix G: Determining n(x) for the Space-charge-neutral Region of a Heterojunction p-type Bottom Material 372
Index 376
A 376
B 376
C 376
D 377
E 377
F 378
G 378
H 378
I 378
J 379
K 379
L 379
M 379
N 379
O 380
P 380
Q 380
R 381
S 381
T 382
U 382
V 382
W 382