Active Layer Materials for Organic Solar Cells

Organic photovoltaic cell (OPV) has emerged as a new competitor to inorganic material-based solar cells, due to its potential application in large area, printable, and flexible solar panels. In particular, OPV cells with bulk heterojunction architecture (BHJ), in which the photoactive layer consists of a bicontinuous blend of an electron donor and an electron acceptor, has allowed power conversion efficiencies (PCEs) over 8 %. Electron donor and electron acceptor materials, with ideal properties are requisite for reaching high PCE. In this chapter, the relationship between molecular structure and photovoltaic property of active layer materials will be discussed, and also the rules of molecular design of organic photovoltaic materials will be presented. Furthermore, the latest progresses of electron donors and electron acceptors, especially for conjugated polymers and the fullerene derivatives, will be introduced.