New Methanofullerenes Containing Amide as Electron Acceptor for Construction Photovoltaic Devices

Three new hydrogen bonding [60]methanefullerenes (PCB-t-BA, PCB-n-BA, and MPCB-t-BA) are synthesized, characterized, and presented for measurement of the photovoltaic properties. In comparison with the PCBM molecule, the ester group was substituted with n-butyric or t-butyric alkyl group in the two compounds. Bulk heterojunction (BHJ) organic photovoltaic devices (OPV) employing the methanofullerenes as acceptor were fabricated and optimized. An improvement of power conversion efficiencies (eta e) was observed upon application in P3HT/PCB-n-BA (eta e = 0.78%) BHJ OPV compared to P3HT/PCBM (eta e = 0.59%) without thermal annealing with the ratio of 1:1 by weight.