Cover Page

Contents

Cover

Title Page

Copyright

Preface

List of Contributors

Chapter 1: AIE or AIEE Materials for Electroluminescence Applications

1.1 Introduction

1.2 EL Background, EL Efficiency, Color Chromaticity, and Fabrication Issues of OLEDs

1.3 AIE or AIEE Silole Derivatives for OLEDs

1.4 AIE or AIEE Maleimide and Pyrrole Derivatives for OLEDs

1.5 AIE or AIEE Cyano-Substituted Stilbenoid and Distyrylbenzene Derivatives for OLEDs

1.6 AIE or AIEE Triarylamine Derivatives for OLEDs

1.7 AIE or AIEE Triphenylethene and Tetraphenylethene Derivatives for OLEDs

1.8 White OLEDs Containing AIE or AIEE Materials

1.9 Perspectives

References

Chapter 2: Crystallization-Induced Phosphorescence for Purely Organic Phosphors at Room Temperature and Liquid Crystals with Aggregation-Induced Emission Characteristics

2.1 Crystallization-Induced Phosphorescence for Purely Organic Phosphors at Room Temperature

2.2 Liquid Crystals with Aggregation-Induced Emission Characteristics

2.3 Conclusions and Perspectives

References

Chapter 3: Mechanochromic Aggregation-Induced Emission Materials

3.1 Introduction

3.2 Mechanochromic Non-AIE Compounds

3.3 Mechanochromic AIE Compounds

3.4 Conclusion

References

Chapter 4: Chiral Recognition and Enantiomeric Excess Determination Based on Aggregation-Induced Emission

4.1 Introduction to Chiral Recognition

4.2 Chiral Recognition and Enantiomeric Excess Determination of Chiral Amines

4.3 Chiral Recognition and Enantiomeric Excess Determination of Chiral Acids

4.4 Mechanism of Chiral Recognition Based on AIE

4.5 Prospects for Chiral Recognition Based on AIE

References

Chapter 5: AIE Materials Towards Efficient Circularly Polarized Luminescence, Organic Lasing, and Superamplified Detection of Explosives

5.1 Introduction

5.2 AIE Materials with Efficient Circularly Polarized Luminescence and Large Dissymmetry Factor

5.3 AIE Materials for Organic Lasing

5.4 AIE Materials for Superamplified Detection of Explosives

5.5 Conclusion

References

Chapter 6: Aggregation-Induced Emission and Applications of Aryl-Substituted Pyrrole Derivatives

6.1 Introduction

6.2 Luminescence Properties of Triphenylpyrrole Derivatives in the Aggregated State

6.3 Applications

6.4 Aggregation-Induced Emission of Pentaphenylpyrrole

6.5 AIEE Mechanism of Pentaphenylpyrrole

6.6 Conclusion

References

Chapter 7: Biogenic Amine Sensing with Aggregation-Induced Emission-Active Tetraphenylethenes

7.1 Introduction

7.2 Fluorimetric Sensing of Biogenic Amines with AIE-Active TPEs

7.3 Summary and Outlook

References

Chapter 8: New Chemo-/Biosensors with Silole and Tetraphenylethene Molecules Based on the Aggregation and Deaggregation Mechanism

8.1 Introduction

8.2 Cation and Anion Sensors

8.3 Fluorimetric Biosensors for Biomacromolecules

8.4 Fluorimetric Assays for Enzymes

8.5 Fluorimetric Detection of Physiologically Important Small Molecules

8.6 Miscellaneous Sensors

8.7 Conclusion and Outlook

References

Chapter 9: Carbohydrate-Functionalized AIE-Active Molecules as Luminescent Probes for Biosensing

9.1 Introduction

9.2 Carbohydrate-Bearing AIE-Active Molecules

9.3 Luminescent Probes for Lectins

9.4 Luminescent Probes for Enzymes

9.5 Luminescent Probes for Viruses and Toxins

9.6 Conclusion

Acknowledgments

References

Chapter 10: Aggregation-Induced Emission Dyes for In Vivo Functional Bioimaging

10.1 Introduction

10.2 AIE Dyes for Macro In Vivo Functional Bioimaging

10.3 Multiphoton-Induced Fluorescence from AIE Dyes and Applications in In Vivo Functional Microscopic Imaging [36]

10.4 Summary and Perspectives

Acknowledgments

References

Chapter 11: Specific Light-Up Bioprobes with Aggregation-Induced Emission Characteristics for Protein Sensing

11.1 Introduction

11.2 In Vitro Detection of Integrin αvβ3 Using a TPS-Based Probe

11.3 Real-Time Monitoring of Cell Apoptosis and Drug Screening with a TPE-Based Probe

11.4 In Vivo Monitoring of Cell Apoptosis and Drug Screening with PyTPE-Based Probe

11.5 Conclusion

Acknowledgments

References

Chapter 12: Applications of Aggregation-Induced Emission Materials in Biotechnology

12.1 Introduction

12.2 AIE Materials for Nucleic Acid Studies

12.3 AIE Materials for Protein Studies

12.4 AIE Materials for Live Cell Imaging

12.5 Conclusion

References

Index

Title Page

Preface

The discovery of new natural phenomena, the unveiling of new physical laws, the development of new methodologies, and the generation of new knowledge are at the core of scientific research. From this viewpoint, the study of light-emitting behaviors of luminogens in an aggregate state is a challenging yet important topic because it may lead to the creation of new photophysical knowledge.

Since the 1950s, studies have shown that the fluorescence of a number of luminophores became weaker or even completely quenched in concentrated solutions or in the solid state. This common photophysical phenomenon is widely known as ‘concentration quenching’ or ‘aggregation-caused quenching’ (ACQ) of light emission. The ACQ process has been studied in great detail, and mature theories have been established. The ACQ effect, however, is harmful in practice, because luminophores are usually used as solid films or aggregates in real-world applications, which hinders them from realizing their full potential. Numerous processes have been employed and many approaches have been developed to prevent the luminophores from aggregating, but these efforts have met with only limited success. The difficulty lies in the fact that chromophore aggregation is an intrinsic natural process when luminophore molecules are located in close vicinity in the condensed phase.

Exactly opposite to the ACQ effect, in 2001 we observed a unique luminogen system in which aggregation played a constructive, instead of destructive, role in the luminescence process: a molecule named 1-methyl-1,2,3,4,5-pentaphenylsilole was found to be almost nonemissive in dilute acetonitrile solution but became highly fluorescent when a large amount of water was admixed with acetonitrile. Because water is a poor solvent of the hydrophobic silole luminogen, addition of water to acetonitrile causes the silole molecules to aggregate in aqueous media. As the light emission is induced by aggregate formation, we coined the term aggregation-induced emission (AIE) for the phenomenon. In the past decade, a large variety of molecules with propeller shapes have been found to show the AIE effect, indicating that AIE is a general, rather than special, photophysical phenomenon.

On the basis of our experimental results, we have rationalized that the restriction of intramolecular rotation (RIR) is the main cause of the AIE phenomenon. In the solution state, intramolecular rotation of the aromatic rotors of the AIE luminogens is active, which serves as a relaxation channel for the excited states to decay nonradiatively. In the aggregate state, however, the intramolecular rotation is restricted owing to the physical constraint involved, which blocks the nonradiative pathway and opens the radiative channel.

The novel AIE phenomenon offers a new platform for researchers to look into the light-emitting processes from luminogen aggregates, from which useful information on structure–property relationships may be collected and mechanistic insights may be gained. Such information and insights will be instructive to the structural design for the development of new efficient AIE luminogens. Furthermore, the discovery of the AIE effect overturns the general belief of ‘concentration quenching’ or ACQ of luminescence processes, opens a new avenue for the development of new luminogen materials in the aggregate or solid state and may spawn new models or theorems for photophysical processes in solution and aggregate states.

As AIE is a photophysical effect concerning light emission in the practically useful solid state, AIE studies may also lead to hitherto impossible technological innovations. In AIE systems, one can take great advantage of aggregate formation, instead of fighting against it. The AIE effect permits the use of highly concentrated solutions of luminogens and their aggregates in aqueous media for sensing and imaging applications, which may lead to the development of fluorescence turn-on or light-up nanoprobes. A probe based on AIE luminogen nanoaggregates is in some sense the organic version of inorganic semiconductor quantum dots, but are superior to the latter in terms of wider molecular diversity, readier structural tunability, and better biological compatibility.

Attracted by this intriguing phenomenon and its promising applications, a number of research groups throughout the world have enthusiastically engaged in AIE studies, and exciting progress has already been made. In response to an invitation from the Wiley editors, we embarked on the preparation of two volumes dedicated to the study of AIE – this volume, Aggregation-Induced Emission: Applications and the related volume, Aggregation-Induced Emission: Fundamentals.

In this volume, we invited a group of active researchers in the area to contribute on the exploration of high-tech applications of AIE luminogens. The technological utilization of AIE materials in the areas of electroluminescence, mechanochromism, chiral recognition, ionic sensing, biomolecule detection, and cell imaging is covered. Their potential applications in room-temperature phosphorescence, liquid crystals, circularly polarized luminescence, organic lasing, and so on are also introduced in this volume.

This book is expected to be a valuable reference to readers who are now working or planning to be involved in the areas of research on organic optoelectronic materials and biomedical sensors. Although we have tried our best to make this book comprehensive, some important work may have inadvertently been omitted, owing to the limitations on the size of the book and the rapid developments in this area of research. The book may contain some overlapping contents in different chapters and possibly even some errors. We hope the readers will provide us with constructive comments, so that we may modify and improve the book in its next edition.

We would like to thank all the authors who have contributed to this book. Without their enthusiastic support, the foundation of this book could not have been be laid. We also thank the Wiley in-house editors, Sarah Hall, Sarah Tilley, and Rebecca Ralf, for their enthusiastic encouragement and technical support. We hope that this book will serve as a ‘catalyst’ to stimulate new efforts, to trigger new ideas, and to accelerate the pace in the research endeavors on the design of new AIE luminogen systems, the establishment of new theoretical models, and the exploration of innovative applications.

Anjun Qin

Department of Polymer Science and Engineering Zhejiang University, China

Ben Zhong Tang

Department of Chemistry, Division of Biomedical Engineering

The Hong Kong University of Science and Technology China

List of Contributors

Chin-Ti Chen Institute of Chemistry, Academia Sinica, Taiwan

Qi Chen National Center for Nanoscience and Technology, China

Zhenguo Chi PCFM Laboratory and DSAPM Laboratory, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry and Chemical Engineering, Sun Yat-sen University, China

Yuping Dong College of Materials Science and Engineering, Beijing Institute of Technology, China

Bao-Hang Han National Center for Nanoscience and Technology, China

Sailing He Center for Optical and Electromagnetic Research, Zhejiang Provincial Key Laboratory for Sensing Technologies, State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, China

Yuning Hong Department of Chemistry, The Hong Kong University of Science and Technology, China

Jacky W.Y. Lam Department of Chemistry, The Hong Kong University of Science and Technology, China

Jing Liang Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore

Chiao-Wen Lin Institute of Chemistry, Academia Sinica, Taiwan

Bin Liu Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore

Jianzhao Liu Department of Chemistry, The Hong Kong University of Science and Technology, China

Jun Qian Center for Optical and Electromagnetic Research, Zhejiang Provincial Key Laboratory for Sensing Technologies, State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, China

Takanobu Sanji Chemical Resources Laboratory, Tokyo Institute of Technology, Japan

Haibin Shi Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore

Masato Tanaka Chemical Resources Laboratory, Tokyo Institute of Technology, Japan

Ben Zhong Tang Department of Chemistry, Institute of Molecular Functional Materials, The Hong Kong University of Science and Technology, Hong Kong, and Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, China

Bin Tong College of Materials Science and Engineering, Beijing Institute of Technology, China

Dan Wang Center for Optical and Electromagnetic Research, Zhejiang Provincial Key Laboratory for Sensing Technologies, State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, China

Ming Wang Beijing National Laboratory, Organic Solids Laboratory, Institute of Chemistry, Chinese Academy of Sciences, China

Jiarui Xu PCFM Laboratory and DSAPM Laboratory, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry and Chemical Engineering, Sun Yat-sen University, China

Wang Zhang Yuan School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, China

Deqing Zhang Beijing National Laboratory, Organic Solids Laboratory, Institute of Chemistry, Chinese Academy of Sciences, China

Guanxin Zhang Beijing National Laboratory, Organic Solids Laboratory, Institute of Chemistry, Chinese Academy of Sciences, China

Yongming Zhang School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, China

Yan-Song Zheng School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, China