Nanogenerators, self-powered systems, blue energy, piezotronics and piezo-phototronics - A recall on the original thoughts for coining these fields

In my research in the last 20 years, a few fields have been coined in the area of energy and electronics during the course of studying piezoelectric-semiconductor nanostructures. These fields are now attracting a worldwide interest and become the focuses of a few communities. This paper reviews the background and initial ideas based on which we introduced the following original concepts and effects: piezoelectric nanogenerators; self-powered systems; hybrid cell; nano energy; triboelectric nanogenerators; pyroelectric nanogenerators; piezotronics; piezo-phototronics; piezophotonics; tribotronics; blue energy; energy for the new era, and entropy for energy utilization. This paper serves as a record of how these fields were started. Finally, a perspective is given regarding to the energy for the new era, application of nanogenerators, piezotronics and self-powered systems.