Recently developed organic photovoltaics (OPVs) show distinct advantages over their inorganic counterparts due to their lighter weight, flexible shape, versatile materials synthesis and device fabrication schemes, and low cost in large-scale industrial production. Although many books currently exist on general concepts of PV and inorganic PV materials and devices, few are available that offer a comprehensive overview of recently fast developing organic and polymeric PV materials and devices. Organic Photovoltaics: Mechanisms, Materials, and Devices fills this gap. The book provides an international perspective on the latest research in this rapidly expanding field with contributions from top experts around the world. It presents a unified approach comprising three sections: General Overviews; Mechanisms and Modeling; and Materials and Devices. Discussions include sunlight capture, exciton diffusion and dissociation, interface properties, charge recombination and migration, and a variety of currently developing OPV materials/devices. The book also includes two forewords: one by Nobel Laureate Dr. Alan J. Heeger, and the other by Drs. Aloysius Hepp and Sheila Bailey of NASA Glenn Research Center. Organic Photovoltaics equips students, researchers, and engineers with knowledge of the mechanisms, materials, devices, and applications of OPVs necessary to develop cheaper, lighter, and cleaner renewable energy throughout the coming decades.
Author(s): Sam-Shajing Sun, Niyazi Serdar Sariciftci
Series: Optical Science and Engineering
Edition: 1
Publisher: CRC Press
Year: 2005
Language: English
Pages: 286
DK963X_c000......Page 1
Organic Photovoltaics: Mechanisms, Materials, and Devices......Page 6
Foreword 1......Page 9
Foreword 2......Page 10
Preface......Page 12
Acknowledgments......Page 14
Editors......Page 16
Contributors......Page 17
Contents......Page 20
Section 1 General Overviews......Page 23
Contents......Page 0
1.1. THE FIRST SOLID-STATE SOLAR CELL......Page 24
1.3. THE FIRST PRACTICAL APPLICATION OF SILICON SOLAR CELLS......Page 25
1.4. TERRESTRIAL APPLICATIONS......Page 26
1.5. THE FUTURE OF PHOTOVOLTAICS......Page 37
REFERENCES......Page 38
Inorganic Photovoltaic Materials and Devices: Past, Present, and Future......Page 39
2.1.2. Focus: Advanced Materials and Processing......Page 40
2.1.4. Increased Specific Power......Page 41
2.2.3. Amorphous Silicon......Page 42
2.2.4. Gallium Arsenide and Related III–V Materials......Page 43
2.2.5. Thin-Film Materials......Page 44
2.3.1. Multijunction III–V Devices......Page 45
2.3.3. Advanced Processing for Low-Temperature Substrates......Page 47
2.3.4. Concentrator Cells......Page 49
2.3.5. Integrated Power Devices......Page 50
2.4.2. Aerospace......Page 52
2.5. SUMMARY AND CONCLUSIONS......Page 53
REFERENCES......Page 54
Natural Organic Photosynthetic Solar Energy Transduction......Page 57
3.2. PHOTOSYNTHESIS IS A SOLAR ENERGY STORAGE PROCESS......Page 58
3.4. PHOTOSYNTHETIC PIGMENTS......Page 59
3.6. ANTENNAS AND ENERGY TRANSFER PROCESSES......Page 61
3.7. PRIMARY ELECTRON TRANSFER IN REACTION CENTERS......Page 64
3.9. CONCLUSIONS......Page 67
REFERENCES......Page 68
Solid-State Organic Photovoltaics: A Review of Molecular and Polymeric Devices......Page 69
4.1.2. Device Characterization......Page 70
4.2.1. Organic Heterojunction Solar Cells......Page 73
4.2.2. Molecular OPVs with Bulk Heterojunctions......Page 76
4.2.3. High-Efficiency Molecular OPVs with Exciton Blocking Layers......Page 80
4.2.4. Open-Circuit Voltage and Tandem Solar Cells......Page 84
4.3.1. Single-Layer Polymer Devices......Page 86
4.3.2. Polymer–Dye Solar Cells......Page 88
4.3.3. Polymer Blend and Multilayer Solar Cells......Page 96
4.4.1. Polymer–Quantum Dot Devices......Page 105
4.4.2. Polymer-Sensitized TiO2......Page 109
4.4.3. Solid State Dye-Sensitized Solar Cells......Page 114
4.5. CONCLUDING REMARKS......Page 116
REFERENCES......Page 117
Section 2 Mechanisms and Modeling......Page 125
Simulations of Optical Processes in Organic Photovoltaic Devices......Page 126
5.1. INTRODUCTION......Page 127
5.2.1. Incoupling of the Photon......Page 129
5.2.3. Exciton Formation......Page 130
5.2.6. Charge Transport......Page 131
5.3. ROUTES TO OPTICAL MODELS OF PPVDs......Page 132
5.4.1. General Assumptions......Page 133
5.4.2. Derivation — the Stack Model......Page 134
5.4.3. Taking Into Account the Substrate......Page 139
5.4.5. Efficiencies......Page 141
5.5. SIMULATIONS AND RESULTS......Page 142
5.5.2. Q-Profile for Different Wavelengths......Page 146
5.5.4. Polychromatic Q-Profile......Page 147
5.5.5.1. Optimizing the Double Layer Structure......Page 149
5.5.5.2. Optimizing the Blend Layer Structure......Page 150
5.5.7.1. Optical Power Efficiency......Page 152
5.5.8. Energy Redistribution......Page 153
5.6. SUMMARY......Page 154
REFERENCES......Page 155
Coulomb Forces in Excitonic Solar Cells......Page 158
6.1.1. Differences Between Conventional and Excitonic Semiconductors......Page 159
6.1.2. Characteristics of Excitonic Semiconductors......Page 160
6.2. CHARGE CARRIER PHOTOGENERATION IN CSCs AND XSCs......Page 161
6.2.1. Forces and Fluxes in XSCs......Page 162
6.2.2. The Chemical Potential Energy Gradient in XSCs......Page 163
6.3. DOPING OSCs......Page 164
6.3.2. Purposely Doped Perylene Diimide Films......Page 165
6.3.3. Superlinear Increase in Conductivity with Doping Density......Page 166
6.3.4. No Shallow Dopants in XSCs......Page 169
6.4.2. Adventitiously Doped XSCs......Page 170
6.4.3. The Poole–Frenkel Mechanism......Page 171
6.4.4. Space Charge Limited Currents......Page 173
6.4.5. Field-Dependent Carrier Mobilities......Page 175
6.5. SUMMARY......Page 176
REFERENCES......Page 177
Electronic Structure of Organic Photovoltaic Materials: Modeling of Exciton- Dissociation and Charge- Recombination Processes......Page 179
7.1. INTRODUCTION......Page 180
7.2. THE FAILURE OF THE STATIC VIEW......Page 181
7.3. THEORETICAL APPROACH......Page 183
7.4. DYNAMICAL ASPECTS......Page 187
7.5.1. Specifically Designed Supramolecular Architectures......Page 191
7.5.2. Donor–Bridge–Acceptor Architectures......Page 192
7.5.3. Symmetry Effects......Page 193
7.5.4. Low-Bandgap Polymers......Page 195
ACKNOWLEDGMENTS......Page 196
REFERENCES......Page 197
Optimization of Organic Solar Cells in Both Space and Energy – Time Domains......Page 201
8.1. INTRODUCTION......Page 202
8.2. FUNDAMENTALS AND CURRENT PROBLEMS OF ORGANIC PHOTOVOLTAICS......Page 203
8.2.1. Photon Absorption and Exciton Generation......Page 206
8.2.4. Carrier Diffusion to the Electrodes......Page 207
8.2.5. Carrier Collection at the Electrodes......Page 208
8.3.1. Block Copolymers and Self-Assembled Supramolecular Nanostructures......Page 209
8.3.2. Design and Development of a –DBAB- Type Block Copolymer for a ‘‘Tertiary’’ Supramolecular Nanostructure......Page 210
8.3.3. Materials and Equipment, Experimental......Page 214
8.3.4. Results and Discussion on Spatial Domain Optimization......Page 216
8.4.1. Background......Page 221
8.4.2. Formulation......Page 222
8.4.3. Results and Discussion......Page 224
8.5. CONCLUSIONS AND FUTURE PERSPECTIVES......Page 229
REFERENCES......Page 230
Section 3 Materials and Devices......Page 233
9.1. INTRODUCTION......Page 234
9.2. PHOTOINDUCED ELECTRON TRANSFER FROM CONJUGATED POLYMERS ONTO FULLERENES......Page 235
9.3. THE BULK HETEROJUNCTION CONCEPT......Page 237
9.4. METAL–INSULATOR–METAL (MIM) PICTURE......Page 240
9.5. BILAYER HETEROJUNCTION DEVICES......Page 242
9.6. BULK HETEROJUNCTION DEVICES......Page 243
9.7. THE OPEN CIRCUIT POTENTIAL,......Page 245
9.8. DOUBLE CABLE POLYMERS......Page 248
REFERENCES......Page 249
Organic Solar Cells Incorporating a p–i–n Junction and a p – n Homojunction......Page 255
10.1. INTRODUCTION......Page 256
10.2.2. Direct Heteromolecular Contact as a Photocarrier Generation Site......Page 257
10.2.3. Three-Layered Cells......Page 260
10.2.4. p–i–n Energy Structure......Page 262
10.2.5. Application of Inorganic Semiconductors to the n-Type Layer......Page 265
10.2.6. Sensitization Mechanism of Photocarrier Generation at Heteromolecular Contacts......Page 266
10.3.2. Photovoltaic Properties vs. Substrate Temperature......Page 268
10.3.3. Nanostructure vs. Substrate Temperature......Page 269
10.3.4. Photocurrent Generation in Co-Deposited Films......Page 271
10.3.5. Three-Layered Cells Incorporating Crystalline–Amorphous Nanocomposite Films......Page 272
10.4.1. Motivation......Page 275
10.4.2. Efficient Purification by Reactive Sublimation......Page 276
10.4.3. pn-Control of a Single Organic Semiconductor by Doping......Page 278
10.4.4. p–n Homojunction in Perylene Pigment Film......Page 282
10.5. CONCLUSION......Page 284
REFERENCES......Page 285
