Front-side illuminated CdS/CdSe quantum dots co-sensitized solar cells based on TiO _2 nanotube arrays

摘要

We fabricated a front-side illuminated CdS/CdSe quantum dots co-sensitized solar cell based on TiO _2 nanotube arrays. The freestanding TiO _2 nanotube arrays were first detached from anodic oxidized Ti foils and then transferred to the fluorine-doped tin oxide to form photoanodes. An opaque Cu _2S with high electrochemical activity was used as the counter electrode. A photovoltaic conversion efficiency as high as 3.01% under one sun illumination has been achieved after optimizing the deposition time of CdSe quantum dots and the length of the TiO _2 nanotube arrays. It is observed that the power conversion efficiency of quantum dots sensitized solar cells from the front-side illumination mode (3.01%) is much higher than that of the back-side illumination mode (1.32%) owing to the poor catalytic activity of Pt to polysulfide electrolytes and light absorption by the electrolytes for the latter.