Advanced Concepts in Photovoltaics
[BOOK DESCRIPTION]
Photovoltaic systems enable the sun's energy to be converted directly into electricity using semiconductor solar cells. The ultimate goal of photovoltaic research and development is to reduce the cost of solar power to reach or even become lower than the cost of electricity generated from fossil and nuclear fuels. The power conversion efficiency and the cost per unit area of the phototvoltaic system are critical factors that determine the cost of photovoltaic electricity. Until recently, the power conversion efficiency of single-junction photovoltaic cells has been limited to approximately 33% - the socalled Shockley-Queisser limit. This book presents the latest developments in photovoltaics which seek to either reach or surpass the Shockley-Queisser limit, and to lower the cell cost per unit area.Progress toward this ultimate goal is presented for the three generations of photovoltaic cells: the 1st generation based on crystalline silicon semiconductors; the 2nd generation based on thin film silicon, compound semiconductors, amorphous silicon, and various mesoscopic structures; and the 3rd generation based on the unique properties of nanoscale materials, new inorganic and organic photoconversion materials, highly efficient multi-junction cells with low cost solar concentration, and novel photovoltaic processes. The extent to which photovoltaic materials and processes can meet the expectations of efficient and cost effective solar energy conversion to electricity is discussed. Written by an international team of expert contributors, and with researchers in academia, national research laboratories, and industry in mind, this book is a comprehensive guide to recent progress in photovoltaics and essential for any library or laboratory in the field.
[TABLE OF CONTENTS]
Chapter 1 Crystalline Silicon Solar Cells with 1 (29)
High Efficiency
Stefan W. Glunz
1.1 Introduction 1 (1)
1.2 Efficiency Limitations 2 (5)
1.2.1 Theoretical Limitations: The Auger 2 (3)
Limit
1.2.2 Practical Limitations 5 (2)
1.3 Screen-printed Al-BSF Solar Cells on 7 (4)
p-type Silicon
1.3.1 Standard A1-BSF Cell 9 (1)
1.3.2 Improved Al-BSF Formation by Boron 10 (1)
Co-doping
1.3.3 Improved Emitter 10 (1)
1.4 Solar Cells with Dielectric Rear 11 (3)
Passivation on p-type Silicon
1.4.1 Rear Passivation Layers 12 (1)
1.4.2 Contacting Schemes 13 (1)
1.4.3 Lifetime Limitations in Boron-doped 13 (1)
p-type Silicon
1.5 Solar Cells on n-type Silicon 14 (6)
1.5.1 n-type BSF Cell Structures 15 (2)
1.5.2 n-type Cell Structures with 17 (1)
Dielectric Rear Passivation
1.5.3 Heterojunction Solar Cells 17 (2)
1.5.4 Back-contacted Back-junction Solar 19 (1)
Cells
1.5.5 Back-contacted Back-junction Solar 20 (1)
Cells with Passivated Contacts
1.6 Conclusion 20 (1)
Acknowledgements 21 (1)
References 21 (9)
Chapter 2 Tandem and Multiple junction Devices 30 (31)
Based on Thin-film Silicon Technology
Christophe Ballif
Mathieu Boccard
Karin Soderstrom
Gregory Bugnon
Fanny Meillaud
Nicolas Wyrsch
2.1 Introduction 30 (2)
2.2 Material Properties 32 (6)
2.2.1 Hydrogenated Amorphous Silicon 32 (2)
(a-Si:H) and its Alloys
2.2.2 Hydrogenated Microcrystalline 34 (4)
Silicon (オc-Si:H) and its Alloys
2.3 Basis of Thin-film Silicon-based 38 (3)
Multiple-junction Devices
2.3.1 Solar Cells Based on Thin Films of 38 (1)
Silicon
2.3.2 Possible Multiple-junction Devices 38 (2)
Based on Thin Films of Silicon
2.3.3 Matching Considerations 40 (1)
2.3.4 Combining Light Management and 40 (1)
High-quality Absorber Layers
2.4 State of the Art 41 (1)
2.5 Current Limitations and Prospective 42 (9)
Concepts
2.5.1 Increasing Light Absorption in the 43 (5)
Absorber
2.5.2 Improvements in Silicon Materials 48 (3)
2.6 Conclusions and Perspectives 51 (1)
References 51 (10)
Chapter 3 Thin-film CdTe Photovoltaic Solar 61 (26)
Cell Devices
Timothy Gessert
Brian McCandless
Chris Ferekides
3.1 Introduction 61 (9)
3.1.1 History of CdTe Photovoltaic Devices 62 (3)
3.1.2 Layer-specific Process Description 65 (5)
for Superstrate CdTe Devices
3.2 Important and Under-reported Processes 70 (11)
3.2.1 Buffer Layers 70 (2)
3.2.2 Incorporation of Cu 72 (2)
3.2.3 Defects and Defect Modeling 74 (5)
3.2.4 Junction Formation and Location 79 (2)
3.3 Conclusions 81 (1)
Acknowledgements 81 (1)
References 81 (6)
Chapter 4 III-V Multi Junction Solar Cells 87 (31)
Simon P. Philipps
Andreas W. Bett
4.1 Introduction 87 (4)
4.2 On the Efficiency of III-V 91 (4)
Multi-junction Solar Cells
4.2.1 Photovoltaic Cells and 91 (2)
Monochromatic Light: A Perfect Match
4.2.2 Towards a Match with the Solar 93 (2)
Spectrum: Stacking Photovoltaic Cells
4.3 The Technological Toolbox to Fabricate 95 (9)
III-V Multi-junction Solar Cells
4.3.1 Epitaxial Growth Methods 96 (2)
4.3.2 Substrates 98 (1)
4.3.3 Epitaxial Growth Concepts 99 (2)
4.3.4 Materials 101(2)
4.3.5 Post-growth Technological Processing 103(1)
4.4 Some Members of the III-V 104(4)
Multi-junction Solar Cell Family
4.4.1 Upright Metamorphic Devices on Ge 104(1)
Substrates
4.4.2 Inverted Metamorphic Multi-junction 105(1)
Solar Cells
4.4.3 III-V on Si 106(2)
4.4.4 Wafer-bonded Multi-junction Solar 108(1)
Cells
4.4.5 Lattice-matched Growth of more than 108(1)
Three Junctions
4.5 Conclusion 108(1)
Acknowledgements 109(1)
References 109(9)
Chapter 5 Thin-film Photovoltaics Based on 118(68)
Earth-abundant Materials
Diego Colombara
Phillip Dale
Laurence Peter
Jonathan Scragg
Susanne Siebentritt
5.1 Introduction 118(4)
5.1.1 Future Requirements for 118(1)
Photovoltaics: 2050 Scenarios
5.1.2 Resource Implications for Thin-film 119(1)
Photovoltaics
5.1.3 Earth-abundant Absorbers 120(2)
5.1.4 The Scope of the Chapter 122(1)
5.2 Kesterite: a Case Study 122(14)
5.2.1 Iso-electronic Substitution: An 122(6)
Introduction to Cu2ZnSnS(Se)4
5.2.2 A Comparison of Phase Equilibria in 128(3)
the Cu-In-Se and Cu-Zn-Sn-Se Systems
5.2.3 Electronic Properties 131(5)
5.3 Preparative Routes to Earth-abundant 136(14)
Absorber Films
5.3.1 Thermodynamic Considerations 137(5)
5.3.2 Kinetic Considerations 142(2)
5.3.3 Preparative Methods 144(5)
5.3.4 Summary 149(1)
5.4 Device Fabrication and Characterization 150(1)
5.5 Other Earth-abundant Materials 151(18)
5.5.1 Phase Equilibria Considerations 152(1)
5.5.2 Phase Stability Considerations 153(4)
5.5.3 Opto-electronic Considerations 157(2)
5.5.4 Application of Criteria of Earth 159(10)
Abundance, Thermodynamics, and
Opto-electronic Properties to Other
Potential Absorber Materials
5.6 Summary and Outlook 169(1)
Acknowledgements 169(1)
References 170(16)
Chapter 6 Chemistry of Sensitizers for 186(56)
Dye-sensitized Solar Cells
Peng Gao
Michael Grutzel
M.D.K. Nazeeruddin
6.1 Introduction 186(6)
6.2 Ruthenium Sensitizers 192(12)
6.2.1 High Molar Extinction Coefficient 195(1)
Sensitizers
6.2.2 Panchromatic Ruthenium Sensitizers 195(5)
6.2.3 Cyclometallated NCS-free Ruthenium 200(1)
Sensitizers
6.2.4 Cyclometallated NCS-free Ruthenium 201(3)
Dyes with a Com/Con Redox Shuttle
6.3 Metal-free Organic Sensitizers 204(13)
6.3.1 Organic Sensitizers and their 206(2)
Cobalt Electrolyte Compatibility
6.3.2 Size Effect of the Donor Groups in 208(1)
the Cobalt Electrolyte Compatibility of
Dyes
6.3.3 Towards Cobalt Electrolyte 209(4)
Compatible Panchromatic Organic Dyes
6.3.4 Donor-Chromophore-Acceptor-based 213(3)
Asymmetric Diketopyrrolopyrrole
Sensitizers
6.3.5 Ullazine-based Sensitizers 216(1)
6.4 Porphyrin Sensitizers 217(6)
6.4.1 Towards High Efficiency and Cobalt 219(2)
Compatible meso-Porphyrin Sensitizers
6.4.2 Towards Panchromatic, High 221(2)
Efficiency and Cobalt Compatible
meso-Porphyrin Sensitizers
6.5 Perovskite Sensitizers for Solid-state 223(6)
Solar Cells
6.5.1 One-step Precursor Solution 225(1)
Deposition
6.5.2 Two-step Sequential Deposition 225(2)
Method
6.5.3 Dual-source Vapour Deposition 227(2)
6.6 Conclusion 229(1)
Acknowledgements 230(1)
References 231(11)
Chapter 7 Perovskite Solar Cells 242(16)
Nam-Gyu Park
7.1 Introduction 242(2)
7.2 Synthesis of Organolead Halide 244(1)
Perovskite
7.3 Crystal Structure and Related Properties 244(2)
7.4 Opto-electronic Properties 246(3)
7.5 Perovskite Solar Cell Fabrication 249(1)
7.6 Device Structures and Performances 250(5)
7.6.1 CH3NH3Pbi3-based Perovskite Solar 250(2)
Cells
7.6.2 Mixed Halide and Non-iodide 252(2)
Perovskite Solar Cells
7.6.3 Planar Heterojunction Without 254(1)
Mesoporous Oxide Layers
7.7 Summary 255(1)
Acknowledgements 255(1)
References 255(3)
Chapter 8 All-oxide Photovoltaics 258(29)
Sven Ridde
Arie Zaban
8.1 Introduction to All-oxide Photovoltaics 258(1)
8.2 Solar Cell Design Rules 259(5)
8.2.1 Light Absorption 259(2)
8.2.2 Charge Transport 261(1)
8.2.3 Selective Contacts 262(1)
8.2.4 Optimized Energy Levels at 263(1)
Interfaces
8.3 Metal Oxides for All-oxide Photovoltaics 264(5)
8.3.1 Electronic Properties 264(2)
8.3.2 Metal Oxide Light Absorber 266(1)
8.3.3 Wide Bandgap Metal Oxides 267(2)
8.4 Cu2O-based Photovoltaics 269(8)
8.4.1 Cu2O Synthesis 269(2)
8.4.2 Electronic and Optical Properties 271(1)
of Cu2O
8.4.3 Cu2O Schottky Junction Cells 272(2)
8.4.4 Cu2O-based Heterojunction Cells 274(2)
8.4.5 Cu2O Homojunction Cells 276(1)
8.4.6 Nano-structured Cu2O-based 276(1)
Photovoltaic Cells
8.5 Further Metal Oxide-based Photovoltaics 277(2)
8.5.1 ZnO-Fe2O3 Heterojunction Solar Cells 277(1)
8.5.2 Bi2O3 Solar Cells 277(1)
8.5.3 Ferro-electric BiFeO3 Solar Cells 278(1)
8.6 Combinatorial Material Science for 279(2)
Novel Metal Oxides
8.6.1 Density Functional Theory 279(1)
8.6.2 Combinatorial Material and Device 280(1)
Fabrication
References 281(6)
Chapter 9 Active Layer Limitations and 287(37)
Non-geminate Recombination in Polymer-Fullerene
Bulk Heterojunction Solar Cells
Tracey M. Clarke
Guanran Zhang
Attila J. Mozer
9.1 Introduction 287(12)
9.2 Active Layer Limitations 299(2)
9.3 Charge Transport and Recombination 301(8)
9.4 Non-Langevin Bimolecular Recombination 309(5)
9.5 Mechanism of Reduced Recombination 314(4)
9.6 Summary and Outlook 318(1)
References 319(5)
Chapter 10 Singlet Fission and 324(21)
1,3-Diphenylisobenzofuran as a Model Chromophore
Justin C. Johnson
Josef Michl
10.1 Introduction 324(6)
10.1.1 Singlet Fission 324(3)
10.1.2 Singlet Fission Chromophores 327(1)
10.1.3 Chromophore Coupling 328(2)
10.2 1,3-Diphenylisobenzofuran (1) 330(11)
10.2.1 The Chromophore 1 330(1)
10.2.2 Polycrystalline Layers of 1 331(4)
10.2.3 Covalent Dimers of 1 335(6)
10.3 Current and Future Activities 341(1)
Acknowledgements 342(1)
References 342(3)
Chapter 11 Quantum Confined Semiconductors for 345(34)
Enhancing Solar Photoconversion through
Multiple Exciton Generation
Matthew C. Beard
Alexander H. Ip
Joseph M. Luther
Edward H. Sargent
Arthur J. Nozik
11.1 Introduction to Colloidal Quantum Dots 345(7)
11.1.1 Tuning of Electronic Properties 345(2)
11.1.2 Competition Between MEG and 347(3)
Hot-carrier Cooling via Phonon Emission
11.1.3 Benefits to Solar Photoconversion 350(2)
11.2 Nanocrystal Synthesis and Physical 352(9)
Properties
11.2.1 Solution Phase Synthesis 352(2)
11.2.2 Shape and Composition Control 354(4)
11.2.3 Measuring Multiple Exciton 358(3)
Generation
11.3 Quantum Dot Solar Cells 361(9)
11.3.1 Quantum Dot Films 361(3)
11.3.2 Quantum Dot Material Selection 364(1)
11.3.3 p-n Heterojunction Quantum Dot 365(3)
Solar Cells
11.3.4 Quantum Junction Solar Cells 368(1)
11.3.5 Multiple Exciton Generation in a 368(1)
Quantum Dot Solar Cell
11.3.6 Multi-junction Solar Cells 369(1)
11.4 Conclusions and Future Directions 370(2)
Acknowledgements 372(1)
References 372(7)
Chapter 12 Hot Carrier Solar Cells 379(46)
Gavin Conibeer
Jean-Fran輟is Guillemoles
Feng Yu
Hugo Levard
12.1 Introduction to Hot Carrier cells 379(1)
12.2 Modelling of Hot Carrier Solar Cells 380(14)
12.2.1 Thermodynamic Analysis for the Hot 380(1)
Carrier Cell
12.2.2 Models for Ideal Hot Carrier Cells 381(2)
12.2.3 Detailed Balance Models and Limit 383(3)
of Efficiency
12.2.4 The Mechanisms of Carrier 386(1)
Thermalization
12.2.5 Modelling of Hot Carrier Solar 387(1)
Cell Efficiency
12.2.6 Modelling of Non-ideal ESCs 388(3)
12.2.7 Monte Carlo Modelling of Real 391(3)
Material Systems
12.2.8 Summary of Modelling Section 394(1)
12.3 Hot Carrier Absorbers: Slowing of 394(6)
Carrier Cooling
12.3.1 Electron-Phonon Interactions 395(1)
12.3.2 Phonon Decay Mechanisms 396(1)
12.3.3 Nanostructures for the Absorber 397(2)
12.3.4 Hot Carrier Cell Absorber 399(1)
Requisite Properties
12.4 Hot Carrier Absorber: Choice of 400(14)
Materials
12.4.1 Analogues of InN 400(3)
12.4.2 Modelling Phonon Properties in 403(6)
Group IV and III-V compounds
12.4.3 Phonon Modulation in Quantum Dot 409(5)
Nanostructure Arrays for Absorbers
12.5 Contacting Hot Carrier Cells 414(5)
12.5.1 Modelling Optimized Materials for 414(3)
Energy Selective Contacts
12.5.2 Triple Barrier Resonant Tunnelling 417(1)
Structures for Carrier Selection and
Rectification
12.5.3 Optical Coupling for Hot Carrier 418(1)
Cells
12.6 Summary and Conclusion 419(2)
References 421(4)
Chapter 13 Intermediate Band Solar Cells 425(30)
Yoshitaka Okada
Tomah Sogabe
Yasushi Shoji
13.1 Introduction 425(3)
13.2 Numerical Analysis of QD-IB Solar Cell 428(3)
Characteristics
13.3 Fabrication of QD-IB Solar Cells 431(18)
13.3.1 Growth and Properties of 431(6)
High-density InAs QD Arrays on High-index
Substrate
13.3.2 InAs/GaAs QD-IB Solar Cells 437(4)
Fabricated on High-index Substrate
13.3.3 Growth and Properties of 441(3)
InAs/GaAsSb QDs with Type-II Band
Alignment
13.3.4 InAs/GaAsSb QD-IB Solar Cells with 444(4)
Type-II Band Alignment
13.3.5 Characteristics of QD-IB Solar 448(1)
Cells under Concentrated Sunlight
13.4 Conclusion and Future Research 449(2)
Acknowledgements 451(1)
References 452(3)
Chapter 14 Spectral Conversion for Thin Film 455(34)
Solar Cells and Luminescent Solar Concentrators
Wilfried van Sark
Jessica de Wild
Zachar Krumer
Celso de Mello Donegci
Ruud Schropp
14.1 Introduction 456(3)
14.1.1 Spectral Conversion 456(2)
14.1.2 This Chapter 458(1)
14.2 Up-conversion for Thin Film Silicon 459(10)
14.2.1 Introduction 459(2)
14.2.2 Up-conversion Results 461(8)
14.3 Luminescent Solar Concentrators 469(14)
14.3.1 Operating Principles 470(1)
14.3.2 Efficiency 471(2)
14.3.3 Alternative Luminescent Species 473(3)
14.3.4 Re-absorption 476(7)
14.4 Conclusion and Outlook 483(1)
Acknowledgements 484(1)
References 484(5)
Chapter 15 Triplet-triplet Annihilation 489(17)
Up-conversion
Timothy W. Schmidt
Murad J.Y. Tayebjee
15.1 Introduction 489(1)
15.2 The Limiting Efficiency of a Single 490(2)
Threshold Solar Cell
15.2.1 Photon Ratchet Model 490(2)
15.3 Up-conversion 492(3)
15.3.1 Summary 495(1)
15.4 Triplet-triplet Annihilation 495(4)
15.4.1 Typical TTA Up-conversion 496(1)
Combinations
15.4.2 Efficiency Considerations 497(2)
15.5 Application to Photovoltaics 499(1)
15.6 Measurement 500(2)
15.7 The Figure of Merit 502(1)
15.8 Prospects 503(1)
References 504(2)
Chapter 16 Quantum Rectennas for Photovoltaics 506(41)
Feng Yu
Garret Moddel
Richard Corkish
16.1 Introduction 506(1)
16.2 History of Quantum Antennas for 507(5)
Photovoltaics Research
16.2.1 Optical and Infrared Rectennas 507(4)
16.2.2 Wireless Power Transmission 511(1)
16.2.3 Radio-powered Devices 512(1)
16.2.4 Radio Astronomy 512(1)
16.3 Research Problems Concerning Rectennas 512(14)
for Photovoltaics
16.3.1 Fundamental Problems 512(8)
16.3.2 Practical Problems 520(6)
16.4 Thermodynamics of Rectennas 526(5)
16.4.1 Broadband Antenna Modeled as a 527(2)
Resistor
16.4.2 Energetics of Thermal Rectification 529(2)
16.5 Quantum Rectification 531(3)
16.6 Broadband Rectification Efficiency 534(2)
Limit
16.7 High-frequency Rectifiers 536(6)
16.7.1 MIM/MIIM Rectifiers 536(1)
16.7.2 New Concepts for High Frequency 537(5)
16.8 Summary and Conclusions 542(1)
Acknowledgements 543(1)
References 543(4)
Chapter 17 Real World Efficiency Limits: the 547(20)
Shockley-Queisser Model as a Starting Point
Pabitra K. Nayak
David Cahen
17.1 Introduction 547(2)
17.2 Efficiency of Different 549(14)
Single-junction Cells and Performance
Analysis Based on Empirical Criteria
17.2.1 Possibilities for Technological 551(2)
Progress
17.2.2 Current Efficiency (JSC/JSC,max, 553(3)
JMP/JSC,max and JMP/JSC)
17.2.3 Photon Energy Loss: Present Status 556(7)
of Single-junction Solar Cells
17.3 Fill Factor and Disorder 563(1)
17.4 Conclusion and Outlook 564(1)
Acknowledgements 564(1)
References 564(3)
Chapter 18 Grid Parity and its Implications for 567(29)
Energy Policy and Regulation
Muriel Watt
Iain MacGill
18.1 Introduction 567(4)
18.1.1 Photovoltaics' Early Promise and 567(1)
Progress
18.1.2 Photovoltaics Goes Mainstream 568(2)
18.1.3 Where next for Photovoltaics 570(1)
18.2 What is Photovoltaics Grid Parity? 571(5)
18.2.1 Issues Around 'Grid Parity' 573(3)
18.3 Past and Projected Photovoltaics and 576(5)
Grid Cost Trajectories
18.3.1 Photovoltaics Costs 576(1)
18.3.2 Grid Costs 577(1)
18.3.3 Implications for Residential 578(2)
Photovoltaics Systems
18.3.4 Implications for Utility-scale 580(1)
Photovoltaics in Wholesale Energy Markets
18.4 The Broader Context of Photovoltaics 581(2)
Deployment
18.4.1 Technology 582(1)
18.4.2 Market Access 582(1)
18.4.3 Social Acceptance 583(1)
18.5 A Changing Context for Photovoltaics 583(6)
Policy Support
18.5.1 The Rationale for Photovoltaics 583(1)
Policy Support
18.5.2 Photovoltaics Specific Policy 584(4)
Approaches to Date
18.5.3 Broader Policy Settings 588(1)
18.6 Implications of Photovoltaics 'Grid 589(3)
Parity' for Energy Markets
18.6.1 Implications of High Photovoltaics 589(1)
Penetration on Other Stakeholders
18.6.2 Emerging Issues and Responses 590(2)
18.7 Conclusion: Photovoltaics as Part of a 592(1)
Broader Transformation
References 593(3)
Subject Index 596