Enhanced photovoltaic performance of a cadmium sulfide/cadmium selenide-sensitized solar cell using an aluminum-doped zinc oxide electrode

Al-doped ZnO nanorods were used as the photoanode of quantum-dot-sensitized solar cells (QDSSCs). Solar cell with CdS/CdSe quantum dots co-sensitized 0.5% Al-doped ZnO nanorods yielded a photovoltaic conversion efficiency of 3.16%, which is higher than that of the cell based on undoped ZnO nanorods (2.30%). This energy conversion efficiency improvement might be attributed to the increased light harvesting efficiency induced by the large amount of quantum dots adsorbed on the large surface area of ZnO NRs, and reduction of transport resistance in the photoanode of QDSSCs with introduction of Al into ZnO structure, which leads to the increasing short-circuit current density. The results also show that recombination rate increases with introduction of Al into ZnO, resulting in the reduction of open-circuit voltage.