Dye-sensitized solar cell utilizing TiO2–sulphur composite photoanode: influence of sulphur precursor content

Abstract

TiO2–sulphur composite films have been prepared and employed as photoanode of dye-sensitized solar cell (DSSC). The influence of sulphur precursor content in terms of thiourea concentration on the structural and optical properties of the sample has been investigated. The anatase and sulphur phases exist in the composite. The secondary phases, namely SO3 and Ti3S4, also present in the composite. The 0.3 M sample possesses the highest reflection and absorption in visible region. Raman characterization reveals that the peak at 474 cm−1 corresponds to the A1g symmetric stretching mode of sulphur. The effect of the sulphur precursor concentration on the performance parameters of the device has also been investigated. The DSSC utilizing the sample with 0.3 M thiourea demonstrates the highest power conversion efficiency, η of 1.80% due to the highest dye loading, the lowest bulk and charge transfer resistance and the longest carrier lifetime. Combining TiO2 with sulphur in composite form was found as an effective way of enhancing the efficiency of the DSSC.