Ferrocene-diketopyrrolopyrrole based nonfullerene acceptors for bulk heterojunction polymer solar cells

Herein we have investigated the photovoltaic properties of ferrocenyl tetracyanobutadiene derivatives of diketopyrrolopyrroles SM1 and SM2 as efficient non-fullerene acceptors along with a donor-acceptor (D-A) conjugated polymer P as a donor for polymer solar cells. The solar cell devices showed a maximum power conversion efficiency of 6.44% and 6.89% for the vacuum dried P: SM1 and P: SM2 active layers respectively. The solar cells based on SM2 showed higher PCE compared to SM1 which may be due to the larger values of both J(sc) and FF. The results presented here demonstrate that employing ferrocene as a donor unit can provide great scope for the molecular design of highly efficient nonfullerene acceptors and provides important progress in the development of non-fullerene organic solar cells.