Versatile third components for efficient and stable organic solar cells

Organic solar cells (OSCs) with a third component, consisting of a donor material, an acceptor material and a third component (organic or inorganic, semiconductor or insulator), received increasing attention in the last five years and the power conversion efficiencies approached 10%. Compared with the traditional binary (two-component) blend, three-component OSCs presented some advantages: broader and stronger absorption, more efficient charge transfer, more efficient charge transport pathways, better charge extraction at the electrodes and improved stability. Various types of third components, such as light-absorbing small molecules or polymers, fullerene or non-fullerene acceptors, metal-or carbon-based nanomaterials, quantum dots, and polymer or small molecule nonvolatile additives were used in OSCs. In this contribution, we review the recent developments in three-component OSCs using various third components. In particular, the absorption complementation, phase separation and the nanostructure in three-component OSCs are addressed.