Photovoltaic performance of PCBM analogs with different ester groups as acceptor in the polymer solar cells

Abstract A series of [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) analogs with different ester structures, such as isopropyl ester (F 1 ), sec-butyl ester (F 2 ), ethyl ester (F 3 ), 2-thiopheneethyl ester (F 4 ), phenethyl ester (F 5 ), and 4-methoxyphenethyl ester (F 6 ), were designed, synthesized, and evaluated for their photovoltaic performance. The optical, electrochemical, morphological, and photovoltaic properties of the molecules were characterized through UV–vis spectroscopy, cyclic voltammetry, and atomic force microscopy; then, the effects of different ester structures on these properties were investigated. Results showed that polymer solar cells (PSCs) with P3HT as a donor and F 1 –F 6 as acceptors displayed different photovoltaic properties. The PSCs with F 1 , F 2 , and F 3 as acceptors showed higher photovoltaic performance than those with F 4 , F 5 and F 6 as acceptors. Moreover, the power conversion efficiency of the former three PSCs exceeded or approached 3.0%, whereas that of the latter three PSCs was below 2.0%. Compared with PCBM, F 2 and F 3 with an aliphatic ester exhibited a slightly better photovoltaic performance, F 1 with isopropyl ester displayed similar photovoltaic properties, and other aromatic ring ester PCBM-like derivatives showed poorer photovoltaic performance.