Organic memory devices have received extensive research interest recently due to their advantages of structural flexibility, processability, light weight and their simple manufacturing processes compared to those employed in inorganic silicon technology. Such devices could have potential applications in flexible electronic components and wearable products. Three types of organic memory devices have been reported in the literature, including resistor-, capacitor- and transistor-type devices. There are several review articles in the field of organic memory but most of them report on a limited subject, such as resistive memory. There is no comprehensive book on tuning different types of memory characteristics through molecular design and morphology manipulation. Thus, I accepted the invitation from the Royal Society of Chemistry to edit this book to provide information on the recent developments of organic electrical memory materials, device fabrication, and switching mechanisms. In order to meet this objective, I have invited the world-leading researchers in this field to write the book chapters, including Prof. En-Tang Kang, Prof. Mitsuru Ueda, Prof. Jian Mei Lu, Prof. Guey-Sheng Liou, Prof. Moonhor Ree, Prof. Jae-Suk Lee, and Prof. Yu-Tai Tao. In this book, different types of charge storage materials, such as organic small molecules, functional polyimides, nonconjugated polymers with pendent chromophores, conjugated polymers, and polymer nanocomposites, are summarized and correlated with their electrical memory characteristics. In addition, various device configurations, including resistor and transistor-type memory, are also discussed in detail along with the defined charge storage mechanisms. The effects of the charge transfer strength, charge trapping/de-trapping ability, surface polarity, interfacial energy barrier, and morphology of the memory active layer on the electrical switching behaviours are also comprehensively discussed in this book. I would like to express my sincere appreciation to the chapter authors for spending their precious time despite their relatively busy schedules. In addition, without the proof-reading and administration work of Professor Cheng-Liang Liu and Dr. Hung Chin Wu, I could not finish this book. I hope that this book will not only provide a fundamental understanding of the chemical and physical aspects of organic electrical memory materials but will also spark future development of advanced high density data storage devices.

Wen-Chang Chen