Synthesis and Characteristics of Fullerene Derivatives with Hexyl Perylene Moieties as N-Type Materials in Organic Solar Cells

Recently, fullerene derivatives have received significant attention due to their potential impacts on the development of high performance organic photovoltaic (OPV) cells. One of the most successful fullerene derivatives thus far is [6, 6]-phenyl-C61-butyric acid methyl ester (PCBM), which is being used as an electron acceptor material. However, PCBM has some disadvantages concerning its application in OPV cells, such as a weak absorption rate in the visible region and a relatively low LUMO level. In the present work, we synthesized a novel fullerene derivative, called hexyl perylene fullerene (HPF), which contains a hexyl perylene moiety. The HPF molecules showed two absorption peaks at 340 nm and 450 nm corresponding to the fullerene and to the perylene moiety, respectively. 1,8-octanedithiol was used as an additive to improve the compatibility between the poly(3-hexylthiophene) (P3HT) and the synthesized HPF The characteristics of an OPV cell composed of ITO/PEDOT:PSS/P3HT:HPF:1,8-octanedithiol/Al were investigated.