Textbook in PDF format Nano energy is a field of studying small-scale, highly efficient energy harvesting, storage, and applications by using nanomaterials and nanodevices. Converting nano-energies in our surroundings is essential to meet the challenges that we are facing in the Internet-of-things era. As a result, various types of nanogenerators have been developed to scavenge energies that are produced in the surrounding environment. This book introduces innovative and high-efficiency technology for mechanical energy harvesting. The book provides an introduction to nanogenerators, which are the newest technological advancement in the field of energy conversion