The photoelectric performance of dye-sensitized solar cells fabricated by assembling pigment–protein complexes of purple bacteria on nanocrystalline photoelectrode

Abstract

Four pigment–protein complexes (PPCs, two types of LH2, LH4 and RC) with near-infrared absorbance were obtained from two typical purple bacteria, and were used to fabricate the visible-NIR responsive DSSC by assembling them on TiO2 film photoanodes. The saturation adsorption quantity of LH2 on TiO2 film was 0.146μg BChlcm−2 in 72h. The short current (Isc) and photoelectric conversion efficiency (η) of DSSC with LH2 sensitized-TiO2 reached 1.46mAcm−2 and 0.49% at the optimal concentration of 46.8μg BChlml−1 LH2, respectively, which are approximately two folds higher than those of LHC-based DSSC to date. The RC-sensitized DSSC reached 1.24mAcm−2 (Isc) and 0.57% (η), which are over three orders of magnitude higher than any other RC-based photovoltaic cells so far. Moreover, the photocurrent response remained stable after several cycles of alternating light and darkness. The results suggested that PPCs could be promising natural sensitizer candidates for fabricating visible–NIR responsive DSSC. And this study provided a new strategy for developing versatile biomimetic energy convertors or photoelectric sensors.