Photovoltaic performance and long-term stability of quasi-solid-state fluoranthene dyes-sensitized solar cells

Two new fluoranthene-based organic dye sensitizers (I and II), in which 7, 12-diphenylbenzo[k]fluoranthene moiety is acted as electron donor, thiophene and phenylethynyl units as electron spacers and carboxylic acid as electron acceptor were successfully applied in quasi-solid-state dye-sensitized solar cells. The quasi-solid-state DSSCs based on the dye I showed the better photovoltaic performance: a maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 66%, a short-circuit photocurrent density (Jsc) of 3.53 mA cm−2, an open-circuit photovoltage (Voc) of 542 mV, and a fill factor (ff) of 0.70, corresponding to an overall conversion efficiency of 1.33% under standard global AM 1.5 solar condition. Moreover, the two sensitizers exhibited good stability during a long-term accelerated aging, in which the photovoltaic parameters retained more than 90% of its initial value even after 1000 h under light soaking at 60 °C.