Zinc stannate nanoneedles for CdS/CdSe quantum dot sensitized solar cells

We report zinc stannate (ZTO) nanoneedles obtained through hydrothermal synthesis as a promising photoanode for CdS/CdSe quantum dot sensitized solar cells. The cell based on ZTO/CdS/CdSe with copper sulfide counter electrode recorded the highest conversion efficiency of 3.13% under 1 sun illumination with improved short-circuit current density of 18.96 mA cm−2 and open-circuit photovoltage of 0.613 V which is several times higher than that of CdS sensitized ZTO cells. The high performance is attributed not only to large accumulation of photo-injected carriers but also to the slow process of recombination as one of the reasons for longer electron lifetime, which results in higher current density and open-circuit voltage, respectively.