Improving the performance of dye-sensitized solar cells by incoporating a novel ZnO:Al charge injection layer

Abstract

In this study, the effect of integrating a ZnO:Al (AZO) charge injection layer into dye-sensitized solar cells (DSSCs) is investigated. The AZO charge injection layer was deposited using a low-cost sol-gel deposition method directly onto fluorine-doped tin oxide (FTO) conducting glass just before TiO2 photoanode coating. The structural and optoelectronic properties of AZO charge injection layer are then investigated as a function of the precursor concentration. The integration of AZO charge injection layer leads to the improvement of power conversion efficiency (PCE) by preventing the electrolyte coming in contact with FTO and improving charge injection from the charge AZO layer. It was found that there is an optimum AZO precursor concentration for charge injection layer deposition and DSSCs fabricated using higher concentration resulted in reduced photovoltaic performance due to reduced light transparency, whilst charge injection layer deposited at lower precursor concentration were found to reduce DSSC performance due to insufficient converage.