Ternary blends for polymer bulk heterojunction solar cells

The objective of this mini-review is to outline current major ternary blends used in the active layer of polymer bulk heterojunction photovoltaic solar cells and to give an insight into the direction of the field. The use of a third-component material in polymer - fullerene blends is described in two sections. On the one hand, the first family of solid state additives enables us to enlarge photon collection by expanding the action spectra of the solar cells. The second section deals with materials used to engineer bulk heterojunction morphology at the nanoscale. The different approaches explored for many of the ternary blend systems suggest the great potential of such mixtures to significantly improve the optoelectronic properties of solar cells on a long-term basis. (C) 2013 Society of Chemical Industry