Open-circuit voltage up to 1.07 V for solution processed small molecule based organic solar cells

• Two new small molecules DCAO3TF and DCAO3TCz were designed and synthesized.
• Both molecules show deep HOMO levels and exhibit a high open-circuit voltage up to 1.07 V.
• Power conversion efficiency of the OSCs based on DCAO3TCz as donor reached 3.63%.

With the goal of increasing the open-circuit voltage, two new solution-processable A–D–A structure small molecule donor materials, named DCAO3TF and DCAO3TCz, using two weak electron-donating units, fluorene and carbazole as the central block have been designed and synthesized for photovoltaic applications. While bulk heterojunction photovoltaic devices based on DCAO3TF:PC61BM and DCAO3TCz:PC61BM as the active layers exhibit moderate power conversion efficiencies of 2.38% and 3.63%, respectively, devices based on DCAO3TF:PC61BM do exhibit an impressively high open-circuit voltage (Voc) up to 1.07 V, which is one of the highest Voc in organic solar cells based on donor:PCBM blend films.

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