Chapter 7: Recent Progress in Porphyrin Derivatives Used in Organic Thin-film Solar Cells

In this chapter, we explain the application of porphyrin materials as organic semiconductors for organic solar cells. The advantages of porphyrin materials are the ease of chemical modification and the tuning of energy levels. As a recent trend, porphyrin derivatives with the light absorption units such as diketopyrrolopyrroles have been often reported. They can largely change their energy levels depending on the type of absorption units. Therefore, porphyrin derivatives are able to behave as not only donor but also acceptor materials. The recent progress of porphyrin semiconductor materials for organic solar cells by the structure type will also be discussed.