Thick‐Film High‐Performance Solar Cells with a C60‐Containing Polystyrene Additive

Abstract

In this study, a C60‐containing polystyrene (PS‐C60) is used as an effective polymer additive for thick‐film high‐performance polymer solar cells, which are necessary for performing roll‐to‐roll mass production in the future. The PS‐C60‐processed device exhibits a power conversion efficiency (PCE) of 10.34 ± 0.10%; the PCE is still high (7.30 ± 0.10%) for an active layer thickness of 450 nm, which is more than twice that observed in non‐additive devices (3.11 ± 0.15%). The usage of PS‐C60 results in an efficient exciton dissociation and charge extraction, less bimolecular recombination, and superior charge transport. These effects lead to an improved device performance, even with a thick active layer. Surprisingly, PS‐C60 also helps the film to retain its morphology at high temperatures, thereby improving its thermal stability. The PS‐C60 device retains ≈90% of the initial PCE after conducting a high‐temperature treatment, whereas a remarkable decrease (≈55%) is observed in case of the non‐additive one. The versatility and applicability of the strategy that is presented in this study can considerably help the development of stable thick‐layer devices in terms of satisfying the requirements of the roll‐to‐roll production of solar cells.