Quantum dot photodetectors Chapter 1. Progress in quantum dot infrared photodetectors Chapter 2. Photodetectors based on Perovskite Quantum Dots Chapter 3. Photoconductive Detectors Based on Perovskite Quantum Dots or Nanocrystals: From Lead Based System to Lead Free System Chapter 4. Solution processable Carbon and Graphene Quantum Dots Photodetectors Chapter 5. Quantum Dot Graphene Heterostructure Nanohybrid Photodetectors Chapter 6. Two Dimensional Materials based Quantum Dots for Wavelength Selective Tunable and Broadband Photodetector Devices Chapter 7. Self Assembled Quantum Dot Photodetector A Pathbreaker in the Field of Optoelectronics. This book presents a comprehensive overview of state of the art quantum dot photodetectors including device fabrication technologies optical engineering manipulation strategies and emerging photodetectors with building blocks of novel quantum dots (e.g. perovskite) as well as their hybrid structured (e.g. 0D 2D) materials. Semiconductor quantum dots have attracted much attention due to their unique quantum confinement effect which allows for the facile tuning of optical properties that are promising for next generation optoelectronic applications. Among these remarkable properties are large absorption coefficient high photosensitivity and tunable optical spectrum from ultraviolet visible to infrared region all of which are very attractive and favorable for photodetection applications. The book covers both fundamental and frontier research in order to stimulate readers interests in developing novel ideas for semiconductor photodetectors at the center of future developments in materials science nanofabrication technology and device commercialization. The book provides a knowledge sharing platform and can be used as a reference for researchers working in the fields of photonics materials science and nanodevices.