This book thoroughly covers polymer (alongside other types of organic) solar cells, focusing on their device physics, performance and perspectives, and the use of conjugated polymers as charge transport layers. Though stressing polymers for solar cells, the chapters allow readers to understand the roles of conjugated polymers in all kinds of organic photovoltaics (OPV) and to inspire OPV design improvements. Often, published review articles or chapters that deal with hybrid solar cells ignore the significance of polymer charge transport layers. This book, though, has a chapter for polymers as transport layers in order to explicitly illustrate their significance for the different types of hybrid solar cells.