Rational Design of Solar Cells for Efficient Solar Energy Conversion

An interdisciplinary guide to the newest solar cell technology for efficient renewable energy Rational Design of Solar Cells for Efficient Solar Energy Conversion explores the development of the most recent solar technology and materials used to manufacture solar cells in order to achieve higher solar energy conversion efficiency. The text offers an interdisciplinary approach and combines information on dye-sensitized solar cells, organic solar cells, polymer solar cells, perovskite solar cells, and quantum dot solar cells. The text contains contributions from noted experts in the fields of chemistry, physics, materials science, and engineering. The authors review the development of components such as photoanodes, sensitizers, electrolytes, and photocathodes for high performance dye-sensitized solar cells. In addition, the text puts the focus on the design of material assemblies to achieve higher solar energy conversion.  This important resource:  Offers a comprehensive review of recent developments in solar cell technology Includes information on a variety of solar cell materials and devices, focusing on dye-sensitized solar cells Contains a thorough approach beginning with the fundamental material characterization and concluding with real-world device application. Presents content from researchers in multiple fields of study such as physicists, engineers, and material scientists Written for researchers, scientists, and engineers in university and industry laboratories, Rational Design of Solar Cells for Efficient Solar Energy Conversion offers a comprehensive review of the newest developments and applications of solar cells with contributions from a range of experts in various disciplines.

Table of Contents:
Biographies xiii List of Contributors xv Preface xix 1 Metal Nanoparticle Decorated ZnO Nanostructure Based Dye‐Sensitized Solar Cells 1 Gregory Thien Soon How, Kandasamy Jothivenkatachalam, Alagarsamy Pandikumar, and Nay Ming Huang 1.1 Introduction 1 1.2 Metal Dressed ZnO Nanostructures as Photoanodes 3 1.2.1 Metal Dressed ZnO Nanoparticles as Photoanodes 4 1.2.2 Metal Dressed ZnO Nanorods as Photoanodes 6 1.2.3 Metal Dressed ZnO Nanoflowers as Photoanodes 8 1.2.4 Metal Dressed ZnO Nanowires as Photoanodes 8 1.2.5 Less Common Metal Dressed ZnO Nanostructures as Photoanodes 10 1.2.6 Comparison of the Performance of Metal Dressed ZnO Nanostructures in DSSCs 10 1.3 Conclusions and Outlook 11 References 13 2 Cosensitization Strategies for Dye‐Sensitized Solar Cells 15 Gachumale Saritha, Sambandam Anandan, and Muthupandian Ashokkumar 2.1 Introduction 15 2.2 Cosensitization 18 2.2.1 Cosensitization of Metal Complexes with Organic Dyes 19 2.2.1.1 Phthalocyanine‐based Metal Complexes 19 2.2.1.2 Porphyrin‐based Metal Complexes 21 2.2.1.3 Ruthenium‐based Metal Complexes 27 2.2.2 Cosensitization of Organic–Organic Dyes 41 2.3 Conclusions 51 Acknowledgements 51 References 52 3 Natural Dye‐Sensitized Solar Cells – Strategies and Measures 61 N. Prabavathy, R. Balasundaraprabhu, and Dhayalan Velauthapillai 3.1 Introduction 61 3.1.1 Mechanism of the Dye‐Sensitized Solar Cell Compared with the Z‐scheme of Photosynthesis 62 3.2 Components of Dye‐sensitized Solar Cell 63 3.2.1 Photoelectrode 63 3.2.2 Dye 64 3.2.3 Liquid Electrolyte 64 3.2.4 Counterelectrode 65 3.3 Fabrication of Natural DSSCs 65 3.3.1 Preparation of TiO2 Nanorods by the Hydrothermal Method 65 3.3.2 Characterization of the Photoelectrode for DSSCs 66 3.3.3 Preparation of Natural Dye 67 3.3.4 Sensitization 68 3.3.5 Arrangement of the DSSC 68 3.4 Efficiency and Stability Enhancement in Natural Dye‐Sensitized Solar Cells 68 3.4.1 Effect of Photocatalytic Activity of TiO2 Molecules on the Photostability of Natural Dyes 69 3.4.1.1 Important Points to be Considered for the Preparation of Photoelectrodes 70 3.4.2 Citric Acid – Best Solvent for Extracting Anthocyanins 70 3.4.3. Algal Buffer Layer to Improve Stability of Anthocyanins in DSSCs 72 3.4.3.1 Preparation of Buffer Layers – Sodium Alginate and Spirulina 73 3.4.4 Sodium‐doped Nanorods for Enhancing the Natural DSSC Performance 75 3.4.4.1 Preparing Sodium‐doped Nanorods as the Photoelectrode 75 3.4.5 Absorber Material for Liquid Electrolytes to Avoid Leakage 77 3.5 Other Strategies and Measures taken in DSSCs Using Natural Dyes 79 3.6 Conclusions 82 References 82 4 Advantages of Polymer Electrolytes for Dye‐Sensitized Solar Cells 85 L.P. Teo and A.K. Arof 4.1 Why Solar Cells? 85 4.2 Structure and Working Principle of DSSCs with Gel Polymer Electrolytes (GPEs) 86 4.3 Gel Polymer Electrolytes (GPEs) 87 4.3.1 Chitosan (Ch) and Blends 88 4.3.2 Phthaloylchitosan (PhCh) and Blends 91 4.3.3 Poly(Vinyl Alcohol) (PVA) 98 4.3.4 Polyacrylonitrile (PAN) 105 4.3.5 Polyvinylidene Fluoride (PVdF) 109 4.4 Summary and Outlook 110 Acknowledgements 111 References 111 5 Advantages of Polymer Electrolytes Towards Dye‐sensitized Solar Cells 121 Nagaraj Pavithra, Giovanni Landi, Andrea Sorrentino, and Sambandam Anandan 5.1 Introduction 121 5.1.1 Energy Demand 121 5.1.1.1 Generation of Solar Cells 122 5.1.2 Types of Electrolyte Used in Third Generation Solar Cells 124 5.1.2.1 Liquid Electrolytes (LEs) 124 5.1.2.2 Room Temperature Ionic Liquids (RTILs) 125 5.1.2.3 Solid State Hole Transport Materials (SS‐HTMs) 126 5.2 Polymer Electrolytes 127 5.2.1 Mechanism of Ion Transport in Polymer Electrolytes 128 5.2.2 Types of Polymer Electrolyte 129 5.2.2.1 Solid Polymer Electrolytes 129 5.2.2.2 Gel Polymer Electrolytes 129 5.2.2.3 Composite Polymer Electrolyte 130 5.3 Dye‐ sensitized Solar Cells 130 5.3.1 Components and Operational Principle 131 5.3.1.1 Substrate 133 5.3.1.2 Photoelectrode 134 5.3.1.3 Photosensitizer 135 5.3.1.4 Redox Electrolyte 137 5.3.1.5 Counter Electrode 140 5.3.2 Application of Polymer Electrolytes in DSSCs 140 5.3.2.1 Solid‐state Dye-Sensitized Solar Cells (SS‐DSSCs) 140 5.3.2.2 Quasi‐solid‐state Dye-Sensitized Solar Cells (QS‐DSSC) 142 5.3.2.3 Types of Additives in GPEs 144 5.3.3 Bifacial DSSCs 148 5.4 Quantum Dot Sensitized Solar Cells (QDSSC) 150 5.5 Perovskite‐ Sensitized Solar Cells (PSSC) 152 5.6 Conclusion 153 Acknowledgements 154 References 154 6 Rational Screening Strategies for Counter Electrode Nanocomposite Materials for Efficient Solar Energy Conversion 169 Prabhakarn Arunachalam 6.1 Introduction 169 6.2 Principles of Next Generation Solar Cells 171 6.2.1 Dye‐sensitized Solar Cells 171 6.2.2 Principles of Quantum Dot Sensitized Solar Cells 173 6.2.3 Principles of Perovskite Solar Cells 174 6.3 Platinum‐ free Counterelectrode Materials 175 6.3.1 Carbon‐based Materials for Solar Energy Conversion 175 6.3.2 Metal Nitride and Carbide Materials 178 6.3.3 Metal Sulfide Materials 179 6.3.4 Composite Materials 182 6.3.5 Metal Oxide Materials 183 6.3.6 Polymer Counterelectrodes 184 6.4 Summary and Outlook 185 References 186 7 Design and Fabrication of Carbon‐based Nanostructured Counter Electrode Materials for Dye‐sensitized Solar Cells 193 Jayaraman Theerthagiri, Raja Arumugam Senthil, and Jagannathan Madhavan 7.1 Photovoltaic Solar Cells – An Overview 193 7.1.1 First Generation Solar Cells 194 7.1.2 Second Generation Solar Cells 194 7.1.3 Third Generation Solar Cells 194 7.1.4 Fourth Generation Solar Cells 195 7.2 Dye‐ sensitized Solar Cells 195 7.2.1 Major Components of DSSCs 196 7.2.1.1 Transparent Conducting Glass Substrate 197 7.2.1.2 Photoelectrode 197 7.2.1.3 Dye Sensitizer 198 7.2.1.4 Redox Electrolytes 199 7.2.1.5 Counterelectrode 200 7.2.2 Working Mechanism of DSSCs 200 7.3 Carbon‐ based Nanostructured CE Materials for DSSCs 201 7.4 Conclusions 216 References 217 8 Highly Stable Inverted Organic Solar Cells Based on Novel Interfacial Layers 221 Fang Jeng Lim and Ananthanarayanan Krishnamoorthy 8.1 Introduction 221 8.2 Research Areas in Organic Solar Cells 222 8.3 An Overview of Inverted Organic Solar Cells 224 8.3.1 Transport Layers in Inverted Organic Solar Cells 227 8.3.2 PEDOT:PSS Hole Transport Layer 227 8.3.3 Titanium Oxide Electron Transport Layer 229 8.4 Issues in Inverted Organic Solar Cells and Respective Solutions 232 8.4.1 Wettability Issue of PEDOT:PSS in Inverted Organic Solar Cells 233 8.4.2 Light‐soaking Issue of TiOx‐based Inverted Organic Solar Cells 234 8.5 Overcoming the Wettability Issue and Light‐soaking Issue in Inverted Organic Solar Cells 235 8.5.1 Fluorosurfactant‐modified PEDOT:PSS as Hole Transport Layer 235 8.5.2 Fluorinated Titanium Oxide as Electron Transport Layer 239 8.6 Conclusions and Outlook 245 Acknowledgements 246 References 246 9 Fabrication of Metal Top Electrode via Solution‐based Printing Technique for Efficient Inverted Organic Solar Cells 255 Navaneethan Duraisamy, Kavitha Kandiah, Kyung‐Hyun Choi, Dhanaraj Gopi, Ramesh Rajendran, Pazhanivel Thangavelu, and Maadeswaran Palanisamy 9.1 Introduction 255 9.2 Organic Photovoltaic Cells 257 9.3 Working Principle 258 9.4 Device Architecture 260 9.4.1 Single Layer or Monolayer Device 260 9.4.2 Planar Heterojunction Device 261 9.4.3 Bulk Heterojunction Device 261 9.4.4 Ordered Bulk Heterojunction Device 261 9.4.5 Inverted Organic Solar Cells 262 9.5 Fabrication Process 263 9.5.1 Hybrid‐EHDA Technique 263 9.5.1.1 Flow Rate 265 9.5.1.2 Applied Potential 265 9.5.1.3 Pneumatic Pressure 265 9.5.1.4 Stand‐off Distance 265 9.5.1.5 Nozzle Diameter 266 9.5.1.6 Ink Properties 266 9.5.2 Mode of Atomization 267 9.5.2.1 Dripping Mode 267 9.5.2.2 Unstable Spray Mode 267 9.5.2.3 Stable Spray Mode 267 9.6 Fabrication of Inverted Organic Solar Cells 267 9.6.1 Deposition of Zinc Oxide (ZnO) on ITO Substrate 268 9.6.2 Deposition of P3HT:PCBM 268 9.6.3 Deposition of PEDOT:PSS 268 9.6.4 Deposition of Silver as a Top Electrode 269 9.7 Device Morphology 272 9.8 Device Performance 273 9.9 Conclusion 277 Acknowledgements 277 References 277 10 Polymer Solar Cells – An Energy Technology for the Future 283 Alagar Ramar and Fu‐Ming Wang 10.1 Introduction 283 10.2 Materials Developments for Bulk Heterojunction Solar Cells 284 10.2.1 Conjugated Polymer–Fullerene Solar Cells 284 10.2.2 Non‐Fullerene Polymer Solar Cells 289 10.2.3 All‐Polymer Solar Cells 290 10.3 Materials Developments for Molecular Heterojunction Solar Cells 291 10.3.1 Double‐cable Polymers 291 10.4 Developments in Device Structures 293 10.4.1 Tandem Solar Cells 295 10.4.2 Inverted Polymer Solar Cells 297 10.5 Conclusions 300 Acknowledgements 300 References 301 11 Rational Strategies for Large‐area Perovskite Solar Cells: Laboratory Scale to Industrial Technology 307 Arunachalam Arulraj and Mohan Ramesh 11.1 Introduction 307 11.2 Perovskite 308 11.3 Perovskite Solar Cells 309 11.3.1 Architecture 310 11.3.1.1 Mesoporous PSCs 310 11.3.1.2 Planar PSCs 313 11.4 Device Processing 313 11.4.1 Solvent Engineering 313 11.4.2 Compositional Engineering 314 11.4.3 Interfacial Engineering 314 11.5 Enhancing the Stability of Devices 316 11.5.1 Deposition Techniques 317 11.5.1.1 Spin Coating 317 11.5.1.2 Blade Coating 319 11.5.1.3 Slot Die Coating 320 11.5.1.4 Screen Printing 321 11.5.1.5 Spray Coating 324 11.5.1.6 Laser Patterning 324 11.5.1.7 Roll‐to‐Roll Deposition 325 11.5.1.8 Other Large Area Deposition Techniques 326 11.6 Summary 329 Acknowledgement 329 References 329 12 Hot Electrons Role in Biomolecule‐based Quantum Dot Hybrid Solar Cells 339 T. Pazhanivel, G. Bharathi, D. Nataraj, R. Ramesh, and D. Navaneethan 12.1 Introduction 339 12.2 Classifications of Solar Cells 341 12.2.1 Inorganic Solar Cells 342 12.2.2 Organic Solar Cells (OSCs) 343 12.2.3 Hybrid Solar Cells 344 12.3 Main Losses in Solar Cells 344 12.3.1 Recombination Loss 345 12.3.2 Contact Losses 345 12.4 Hot Electron Concept in Materials 346 12.5 Methodology 347 12.5.1 Hot Injection Method 348 12.5.1.1 Nucleation and Growth Stages 349 12.5.1.2 Merits of this Method 350 12.6 Material Synthesis 350 12.6.1 CdSe QD Preparation 350 12.6.2 QD–βC Hybrid Formation 351 12.7 Identification of Hot Electrons 351 12.7.1 Photoluminescence (PL) Spectrum 351 12.7.2 Time‐correlated Single Photon Counting (TCSPC) 355 12.7.3 Transient Absorption 357 12.8 Quantum Dot Sensitized Solar Cells 360 12.8.1 Working Principle 360 12.8.2 Device Preparation 361 12.8.2.1 Preparation of TiO2 Nanoparticle Electrode 361 12.8.2.2 QDs Deposition on TiO2 Nanoparticle 362 12.8.2.3 Counterelectrode and Assembly of QDSSC 362 12.8.3 Performance 362 12.9 Conclusion 363 References 363 Index 369

About the Author :
Alagarsamy Pandikumar, Ph.D., is a Scientist at the Functional Materials Division, CSIR-Central Electrochemical Research Institute, and leads the Solar Energy Materials Research Group. Ramasamy Ramaraj, Ph.D., is a CSIR-Emeritus Scientist in the School of Chemistry, at Madurai Kamaraj University, where he continues his research work on photoelectrochemistry.