Cr-doped TiO_2 nanotubes with a double-layer model: An effective way to improve the efficiency of dye-sensitized solar cells

摘要

Dye-sensitized solar cells (DSSCs) have been emerging as a potential alternative to photovoltaic devices, which convert incident light into electric energy. However, the power conversion efficiency of DSSCs is currently too low for them to be used in commercial applications. Hence, further improvements in efficiency are necessary. Here, we have designed a DSSC with a double-layer structure, in which the top layer consists of a mixture of TiO2-P25 and Cr-doped TiO2 nanotubes (Cr-TNTs). Based on analyses using photoluminescence spectroscopy, Xray photoelectron spectroscopy, and electrochemical impedance spectroscopy, we have demonstrated the effect of Cr-TNTs on the separation of photogenerated electron-hole pairs. A photoconversion efficiency (eta) of 11.05% was obtained by using the Cr-doped TiO2 material as compared to 9.05% for the un-doped TiO2 nanotubes.