Bulk heterojunction organic photovoltaic devices based on small molecules featuring pyrrole and carbazole and 2-(4-nitrophenyl)acrylonitrile acceptor segments as donor and fullerene derivatives as acceptor

The bulk heterojunction photovoltaic devices based on based on low band gap donor–acceptor (D–A) small molecules, with pyrrole (P) and carbazole (C) as donor and 2- (4-nitroohenyl) acceptor units as electron donor and (6,6)-phenyl- C60 – butyric acid methyl ester (PCBM) and modified PCBM i.e. F as electron acceptor were fabricated and characterized. The power conversion efficiency (PCE) of the BHJ organic solar cells based on P: PCBM, C: PCBM, P:F and C:F cast from the THF solvent was 1.20%, 1.46%, 1.90%, 2.06%, respectively. The enhanced PCE for the devices based on F as compared to the PCBM may be due to the both increased short circuit current (Jsc) and open circuit voltage (Voc). The BHJ organic solar cells based on P:F and C:F blends cast from mixed DIO/THF solvent exhibit over all PCE of 2.41% and 3.13%, respectively.

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► Small molecule donors containing carbazole, pyrrole and 2-(4-nitrophenyl)acrylonitrile segments have developed.
► The organic solar cells using them showed PCE up to 3.13%.
► Carbazole containing dye exhibited higher efficiency due to better hole mobility.
► Blends cast from mixed solvents improved charge transport due to enhanced crystallinity.