Impact of the selectivity of titanium dioxide on photovoltaic performance of anthocyanin-sensitized solar cells

Abstract

ABSTRACT The natural selectivity of titanium dioxide (TiO2) using the anthocyanins extracted from frozen blueberry fruit has been investigated for the improvement of the natural dye-sensitized solar cell. The main drawback of the dye-sensitized solar cell-based natural dyes is the low efficiency caused by the weak binding between natural dye molecules with TiO2 film. High-efficiency dye-sensitized solar cells use the synthetic organic dyes, which are most frequently anchored on metal oxide photoanode through the carboxylic group. Herein, the addition of carboxyl group by the acidification of crude blueberry extract with acetic acid was provided. The carboxyl group is proposed to improve the anchorage of the anthocyanin dye molecules onto the surface of TiO2. Optical analysis and atomic force microscopy show the increase of the visible absorbance and the uniform anchoring of the natural dye molecules over the whole TiO2 film causing a higher dye loading. Dye-sensitized solar cells were fabricated using natural dye obtained by the acidification with hydrochloric acid and acetic acid. Beneficial effect of the carboxylic groups in the anchorage of the natural dye molecules onto the surface of TiO2 was confirmed. The best photovoltaic efficiency of 0.722% under 1 sun was achieved by the dye acidification with acetic acid.