This book "Optoelectronic Properties of Vertical Organic Field Effect Transistors," explores the fascinating world of organic semiconductor devices and their optoelectronic properties. The book is a comprehensive guide to the working principle, fabrication, and characterization of vertical organic field effect transistors, with a focus on their potential applications in optoelectronic devices. The book begins with an introduction to the field of organic semiconductors, explaining the basics of molecular electronics, organic semiconductors, and their unique properties. The author then delves into the detailed working principle and fabrication processes for creating vertical organic field effect transistors, providing an in-depth analysis of their electrical and optical properties. The latter part of the book covers the potential applications of these transistors in various optoelectronic devices, including photodetectors, organic light-emitting diodes, and organic solar cells. The author explores the underlying mechanisms behind these applications and provides a comprehensive review of recent developments in the field. Overall, "Optoelectronic Properties of Vertical Organic Field Effect Transistors" is an essential reference for researchers, students, and professionals interested in the exciting field of organic semiconductors and their potential applications in optoelectronics. It offers a comprehensive overview of the field and provides valuable insights into the working principle, fabrication, and optoelectronic properties of vertical organic field effect transistors.