This book surveys the key developments in the science and engineering of the state-of-the-art materials for clean energy. The book provides a broad overview of materials for photovoltaics, solar energy conversion, thermoelectrics, piezoelectrics, supercapacitors, rechargeable batteries, fuel cells, and hydrogen production and storage. Each of these topics is covered by an experienced international group of contributors, all of whom are experts in their respective fields. This is a valuable resource for readers wanting to delve into research for maximizing the efficiency of alternative energy approaches.