Isatylidene malononitrile derived acceptors for fullerene free organic solar cells

New electron withdrawing moieties derived from isatin and its thiophene analogue were successfully incorporated into A-D-A structured molecular acceptors for polymer solar cell applications. The optical absorption and electrochemical properties of the new materials were investigated. The new acceptors showed low LUMO energy level, broad absorption in visible and near IR region and good miscibility with polymer donor, PTB7-Th. The solar cell devices based on the new electron acceptors and polymer electron donor, PTB7-Th achieved moderate performances. This work indicates that isatin related structures can be useful building blocks for small molecular acceptors.