Recent progress in organic electronic devices has been remarkable, yet understanding key processes like the behaviour of polarons and excitons in organic semiconductors remains challenging. Innovations in magnetic resonance techniques, such as ODMR and EDMR, have recently provided detailed insights into electron spin states, aiding in the understanding and development of these devices.

This book provides an overview of magnetic resonance in organic semiconductor devices, including a framework of the underlying spin physics. It starts with an introduction of organic electronic and optoelectronic devices. Basic principles of optical and electrical detection are included, as well as the conventional microwave detection of electron paramagnetic resonance (EPR) for organic devices. The details of a magnetic resonance spectrometer are presented as well as operando conditions (measurements under real working conditions). The details for experimental setup are provided. This book will also include emerging research in the field of organic neuromorphic devices, and aims to offer essential knowledge for researchers, developers, and students interested in applying magnetic resonance methods to electronic and optoelectronic devices.

Naoki Asakawa is serving as Principal Investigator at the Emergent Polymer Science Laboratory, Gunma University, Japan. He earned his Bachelor Engineering degree from the Department of Polymer Chemistry, Tokyo Institute of Technology (Tokyo Tech) in 1991, followed by his Master of Engineering degree in 1993 and Doctoral degree in 1996 under the supervision of Prof. Isao Ando, also from the Department of Polymer Chemistry, Tokyo Tech. During his doctoral studies, he conducted research at the Chemistry Department, Washington University in St. Louis (1993-1994) as a Visiting Scholar under the super- vision of Professor Jacob Schaefer. He began his academic career as an Assistant Professor in the Department of Biomolecular Engineering, Tokyo Tech (1994-2006). Subsequently, he was appointed as Designated Associate Professor at the Institute of Scientific and Industrial Research (ISIR), Osaka University (2006-2009) as a collaborator with Profs. Yasushi Hotta, Teruo Kanki, Hitoshi Tabata and Tomoji Kawai. He then served as Associate Professor and Principal Investigator in the Department of Chemistry and Chemical Biology, Graduate School of Engineering, Gunma University (2009-2019) before becoming a Full Professor in the Molecular Science Division, Graduate School of Science and Technology, Gunma University, Japan (2019-present). His research interests encompass the development of bioinspired neuromorphic organic electronic devices using molecular dynamics. Additionally, he is dedicated to advancing and applying non-invasive characterization techniques utilizing magnetic resonance spectroscopy for these devices.

Kunito Fukuda has joined to Emergent Polymer Science Lab, Moleculra Science Division, Gunma University, Japan, since 2023. He received his Bachelor of Engineering degree from the Department of Applied Chemistry and Biological Sciences, Faculty of Engineering, Gunma University in 2012, his Master of Engineering degree from the Graduate School of Engineering, Gunma University in 2014, and his doctoral degree of science and technology from the Graduate School of Science and Technology, Gunma University in 2017. He is hired as an assistant professor at Molecular Science Division, Graduate School of Science and Technology, Gunma University, Japan (2023-present). His research interests include the development and investigation of electron spin resonance methods for the analysis of organic semiconductor devices and the construction of bio-inspired information processing mechanisms using magnetic resonance.

Preface

Author biographies

1 Introduction

2 Principle of experiment

3 Development of electron spin resonance apparatus for p-conjugated molecular devices

4 Construction of a variable-frequency ESR/EDMR measurement system using a waveguide window-equipped cavity

5 Progress of magnetic resonance spectroscopy for organic devices

6 Elucidation of spin-dependent processes in pentacene devices using EDMR

7 Impact of molecular orientation on spin-dependent processes in pentacene devices

8 Conclusion