Series Editor’s Foreword xv

About the Editors xvii

Preface xix

Acknowledgments xxi

1 Physics and Photophysics of Quantum Dots for Display Applications 1
Einav Scharf, Uri Banin

1.1 Introduction 1

1.2 Quantum Confinement and Band Structure 1

1.3 Absorption Spectrum 4

1.4 Charge Carrier Dynamics 6

1.5 Surface Passivation and Heterostructure Band Alignment 8

1.6 Emission Intermittency (Blinking) and Stability 9

1.7 Emission Linewidth 12

1.8 Dimensionality Effects 15

1.9 Collective Emission 16

1.10 Summary and Outlook 18

References 18

2 Quantum Dot Material Systems, Compositional Families 23
Sudarsan Tamang, Karl David Wegner, Peter Reiss

2.1 Introduction 23

2.2 II?VI Semiconductor QDs 25

2.2.1 Cadmium Chalcogenide QDs 25

2.2.2 Zn Chalcogenide QDs 27

2.3 III?V Semiconductor QDs: Overview and Properties 35

2.3.1 Introduction 35

2.3.2 Indium Phosphide Quantum Dots 37

2.3.3 Indium Arsenide Quantum Dots 47

2.4 More Recent Families of QDs 50

2.4.1 I?III?VI Chalcopyrite-type QDs 50

2.4.2 Metal Halide Perovskite NCs 54

2.5 Summary and Outlook 60

References 62

3 Principles and Practices for Quantum Dots Synthesis 81
Derrick Allan Taylor, Justice Agbeshie Teku, Jong-Soo Lee

3.1 Introduction 81

3.2 Principles of Colloidal Quantum Dot Synthesis 84

3.2.1 Basic Chemistry of Quantum Dot Synthesis 84

3.2.2 Innovatory Experimental Techniques for Monitoring Evolving Nanocrystals 93

3.2.3 Colloidal Quantum Dots (II?VI and III?V) 94

3.3 Practices of Colloidal Quantum Dot Synthesis 95

3.3.1 Practices 98

3.3.2 Post-synthetic Methods 104

3.4 Summary and Outlook 112

References 114

4 Quantum Dot Enhancement Film 131
Zhong Sheng Luo, Jeff Yurek

4.1 Introduction 131

4.2 Understanding Color for Displays 132

4.2.1 Measuring Display Color Performance: Chromaticity Gamut 134

4.2.2 NTSC 1953 in Practice 135

4.2.3 LCDs and Display Color in the 1990s and 2000s 136

4.3 Color in the Modern Era ? Defining the Ultimate Visual Experience 138

4.3.1 Color Volume 139

4.3.2 High Dynamic Range 141

4.3.3 Clarity 142

4.4 Quantum Dots for QDEF Applications 143

4.4.1 Quantum Dot Wavelength Tunability 144

4.4.2 Narrower Spectrum for Better Color 145

4.5 Quantum Dot Enhancement Film 146

4.5.1 Origins of the QDEF Concept 146

4.5.2 Design Requirements 149

4.5.3 Resin System 150

4.5.4 Barrier Film 150

4.5.5 QD Coating 152

4.5.6 QDEF Fabrication Process 152

4.5.7 QDEF in a Display 154

4.5.8 Heavy Metals and Environmental Regulation 155

4.6 Barrierless Quantum Dot Enhancement Film 156

4.6.1 QD Requirements for Barrierless QDEF 157

4.6.2 Construction and Manufacturing 158

4.6.3 Application 158

4.7 Quantum Dot Diffuser Plate 159

4.7.1 Quantum Dot Requirement 159

4.7.2 Construction and Manufacturing 160

4.7.3 Application 161

4.8 Summary and Outlook 161

References 162

5 Quantum Dot Color Conversion for Liquid Crystal Display 167
Zhifu li, Ji li, Yanan Wang, Hanming li

5.1 Introduction 167

5.2 Thin-film Transistor Liquid Crystal Display 168

5.2.1 Color Perception of Human Eyes 168

5.2.2 Basic Structure and Principle of Liquid Crystal Display 169

5.2.3 Advantages of Quantum Dot Liquid Crystal Display 172

5.3 Quantum Dot Color Conversion for Liquid Crystal Display 173

5.3.1 Quantum Dot Backlight 173

5.3.2 Quantum Dot Color Filter 178

5.4 Summary and Prospects 191

References 193

6 Quantum Dot (QD) Color Conversion for QD-Organic Light-Emitting Diode 197
Keunchan Oh, Hyeokjin Lee, Gakseok Lee, Taehyung Hwang

6.1 Introduction to Quantum Dot-Organic Light-emitting Diode 197

6.2 Color Conversion Materials 199

6.2.1 Quantum Dots in QD-OLED 200

6.2.2 Optical Scattering Particle 204

6.2.3 Surface Ligand Modification 207

6.2.4 Photo Enhancement and Degradation 210

6.3 Color Conversion Architecture 212

6.3.1 Bank 212

6.3.2 Color Filter 214

6.3.3 Optical Recycling Layer 215

6.3.4 Reflection 217

6.4 Inkjet Printing of CCM 218

6.4.1 Inkjet Equipment and Inspection 219

6.4.2 Rheological Properties of Colloidal QD Ink 220

6.4.3 Large Area Uniformity 224

6.5 Conclusion and Future Work 225

References 226

7 Quantum Dots for Augmented Reality 231
Jason Hartlove

7.1 Why Quantum Dots for Augmented Reality? 231

7.2 Augmented Reality Glasses: The Need for High-efficiency Small Emitters 232

7.2.1 ARG Requirements 232

7.2.2 Display Engine Approaches 235

7.3 QD Color Conversion Performance and Reliability Requirements 247

7.3.1 Quantum Dot PLQY 247

7.3.2 Quantum Dot Absorption 248

7.3.3 Flux Stability 249

7.4 Summary and Outlook 250

References 251

8 CdSe-based Quantum Dot Light-emitting Diodes 253
Yiran Yan, Longjia Wu, Weiran Cao, Xiaolin Yan

8.1 Overview of Quantum Dot Light-emitting Diode Development 253

8.2 Functional Layers 255

8.2.1 QD-emitting Layer 255

8.2.2 Hole Transport Layer 260

8.2.3 Electron Transport Layer 262

8.3 Aging Mechanism 264

8.3.1 Degradation Mechanism 264

8.3.2 Positive Aging Mechanism 272

8.4 Summary and Outlook 277

References 277

9 Quantum Dot Light-emitting Device Materials, Device Physics, and Fabrication: Cadmium-free 283
Igor Coropceanu, Heeyoung Jung, Christian Ippen

9.1 Introduction 283

9.1.1 Benefits of Quantum Dot Light-emitting Devices 283

9.1.2 Why Cd-free QD-LED? 284

9.2 Survey of Materials 285

9.2.1 General Considerations 285

9.2.2 Indium Phosphide 286

9.2.3 Zinc Telluride Selenide 290

9.2.4 I-iii-vi 293

9.3 Surface Chemistry 293

9.3.1 General Introduction to NC ? Organic Interface 293

9.3.2 Inorganic Termination 293

9.3.3 Anchoring Group 294

9.3.4 Ligand Body 294

9.3.5 Organic Ligand Exchange for Improved Charge Transport 295

9.3.6 Inorganic and Mixed Organic/Inorganic Surface Treatments 296

9.4 Device Physics and Fabrication 298

9.4.1 Device Architectures 298

9.4.2 Evaluation Metrics 300

9.4.3 HTL Optimizations 301

9.4.4 ETL Optimizations 302

9.4.5 Positive Aging 302

9.4.6 Degradation Mechanisms 303

9.5 Patterning for Display Fabrication 305

9.5.1 General Considerations 305

9.5.2 Optical Methods 306

9.5.3 Inkjet Printing 308

9.6 Summary and Outlook 309

9.6.1 Performance Development of Cd-free vs. Cd-based QD-LEDs 309

9.6.2 What is Still Missing for Cd-free QD-LEDs? 311

References 311

10 Quantum Dot Light-emitting Diode Panel Process: Inkjet Printing 323
Dong Jin Kang, Changhee Lee

10.1 Inkjet Printing Technology for QD Patterning in Full-color Displays 323

10.2 Ink Formulation for Inkjet-Printed QD-LED Displays 325

10.2.1 Quantum Dot Inks 325

10.2.2 Organic Charge-transport Material Ink 328

10.2.3 Inorganic Charge-transport Material Inks 331

10.3 Inkjet Printing Processes and Device Performance of QD-LED Display Panels 331

10.3.1 Device Structure and Operation Mechanism of QD-LEDs 331

10.3.2 Device Characteristics of QD-LEDs 333

10.3.3 Inkjet Printing Processes for Fabricating QD-LED Display Panels 335

10.3.4 Drying and Thermal Baking Processes for QD-LED Panels 339

10.3.5 Device Performance of Inkjet-printed QD-LED Display Panels 342

10.4 Current Challenges in Inkjet Printing for QD-LED Display and Future Outlook 347

10.5 Summary and Outlook 348

References 349

11 Photolithographic Patterning Techniques for Quantum Dot Light-emitting Diodes 355
Yanzhao Li, Shaoyong Lu, Zhuo Chen, Zhuo Li, Xiangbing Fan, Peng Bai, Haoyu Yang, Dong li

11.1 Introduction 355

11.2 Photolithography Technology 357

11.2.1 Basics of Photolithography 357

11.2.2 Photolithographic Patterning of Quantum Dots 359

11.3 Indirect Photoresist-assisted Photolithographic Patterning of Quantum Dots 360

11.3.1 Protective Photoresists 360

11.3.2 Sacrificial Photoresists 363

11.4 Direct Photoresist-free Photolithographic Patterning of Quantum Dots 366

11.4.1 Patterning Using Native Ligands 367

11.4.2 Patterning Through Ligand Exchange 374

11.4.3 Photolithographic Patterning for Maintaining Photophysical Properties of Quantum Dots 377

11.5 Industrial Progress 381

11.6 Summary and Outlook 382

References 383

12 Quantum Dots in Light-emitting Diodes for General Lighting 387
Benjamin Mangum, Juanita Kurtin

12.1 Benefits of Quantum Dots for Illumination 387

12.2 Illumination Landscape: The Need for Narrow Emitters 387

12.2.1 Background: Blackbody Emitters vs. LEDs 387

12.2.2 Making White LEDs: Spectral Engineering 390

12.2.3 Background: Color Metrics 392

12.2.4 The Ideal Spectrum and Theoretical Maximums 395

12.3 SSL Devices and Solution Development 399

12.3.1 Power Classes 399

12.3.2 Quantum Dots for Illumination 400

12.3.3 Form Factor 401

12.3.4 Pairing QDs with Other Phosphors 403

12.4 QD Performance and Reliability Requirements 405

12.4.1 QD Performance Requirements: PLQY 406

12.4.2 QD Performance Requirements: FWHM 406

12.4.3 QD Performance Requirements: Flux Droop 407

12.4.4 Performance Requirements: Thermal Droop 408

12.4.5 Reliability Testing: LM80 testing 408

12.4.6 Reliability Testing: Color Point Shift 409

12.4.7 Reliability Testing: Lumen Maintenance 410

12.5 Summary and Outlook 411

References 412

13 Quantum Dot Photodetector Technology 415
Pawel Malinowski, Itai Lieberman, Jonathan S. Steckel, Andras Pattantyus-Abraham

13.1 Introduction to Sensing with Quantum Dots 415

13.1.1 Photoconductive Devices 416

13.1.2 Photodiodes 416

13.1.3 Phototransistors 417

13.1.4 Other Light Sensing Techniques 418

13.2 Figures of Merit for QD Sensors 418

13.2.1 QD Films and Stacks 418

13.2.2 Photodetector Performance Metrics 419

13.2.3 Image Sensors Performance Metrics 423

13.2.4 Reliability 425

13.3 QD Photodetector Materials and Devices 426

13.3.1 QD Core and Photodetectors 426

13.3.2 QDPD Comparison 431

13.3.3 Evolution of QD Image Sensors 431

13.4 Conclusion and Outlook 434

13.4.1 Use Cases and Applications 434

13.4.2 Outlook 438

References 439

14 Future of Quantum Dots in Displays and Beyond 445
Peter Palomaki

14.1 Introduction 445

14.2 Implementation of QDs Past, Present, and Future 446

14.2.1 Past Technologies 446

14.2.2 Present Technologies 447

14.2.3 Future Technologies 447

14.3 QD Materials 452

14.3.1 CdSe and InP 452

14.3.2 Perovskite 453

14.3.3 I-III-VI QDs 455

14.3.4 Nitrides 456

14.3.5 Material Usage 456

14.3.6 Anisotropic QD Systems 458

14.3.7 Stability 460

14.4 Optical Properties 462

14.4.1 Linewidth 462

14.4.2 Light Absorption 465

14.4.3 Spectral Engineering and Re-absorption 465

14.4.4 QDs and Phosphors 466

14.4.5 Four or More Primaries 467

14.5 Regulatory 468

14.6 Non-display Applications 470

14.6.1 Solar Spectrum Engineering 470

14.6.2 QD Solar Cells 471

14.7 Summary 472

References 473

Index 477