Recent advances in photo-anode for dye-sensitized solar cells: a review

Dye-sensitized solar cell (DSSC) attracts immense interest in the last few decades due to its various attractive features such as low production cost, ease of fabrication and relatively high conversion efficiency, which make it a strong competitor to the conventional silicon-based solar cell. In DSSC, photo-anode performs two important functions, viz. governs the collection and transportation of photo-excited electrons from dye to external circuit as well as acts as a scaffold layer for dye adsorption. The photo-anode usually consists of wide band gap semiconducting metal oxides such as titanium dioxide (TiO2) and zinc oxide (ZnO) deposited on the transparent conducting oxide substrates. The morphology and composition of the semiconductor oxides have significant impact on the DSSC photovoltaic performance. Therefore, enormous research efforts have been undertaken to investigate the influences of photo-anode modifications on DSSC performance. The modifications can be classified into three categories, namely interfacial modification through the introduction of blocking and scattering layer, doping with non-metallic anions and metallic cations and replacing the conventional mesoporous semiconducting metal oxide films with one-dimensional or two-dimensional nanostructures. In the present review, the previously mentioned modifications on photo-anode are summarized based on the recent findings, with particular emphasis given to published works for the past 5years. Copyright (c) 2017 John Wiley & Sons, Ltd.