This book presents the applications of nanomaterials and nanostructures in photovoltaic solar cells, elaborates how they can help achieve high photoelectric conversion efficiency, and introduces readers to the important work done in this field. It covers the basic physical properties of semiconductors and nanomaterials and the formation and characteristics of the p–n junction and the heterojunction; the basic working principle and structures of nano photovoltaic cells; the important parts of nano photovoltaic cells, namely nano surface trapping and electrodes, respectively; nano solar cells based on quantum dots, quantum wires, and organic-inorganic hybrid nano photovoltaic cells; and some reported high-efficiency photovoltaic cells. It also discusses various device structures and important growth techniques for obtaining nanomaterials for solar cells. The book will serve as a useful reference or textbook for researchers, teachers, engineers, and graduate students.