Investigation on the surface modification of TiO₂ nanohexagon arrays based photoanode with SnO₂ nanoparticles for highly-efficient dye-sensitized solar cells

An efficient-photoanode for the dye-sensitized solar cells (DSSCs) should have several features, such as high dye-uploading, favorable energy band-gaps and excellent capability in electronic-transport. Herein, TiO₂ nanohexagon arrays (TNHAs) were fabricated by using an electrochemical anodization process. Then, TNHAs were attached onto the FTO glass for front-illuminated approach of the DSSCs. SnO₂ is a promising wide band-gap material for DSSCs due to its high electron-mobility. To enhance the performance of DSSCs, SnO₂ nanoparticles were offered into the TNHAs by using a one-step facile immersion approach in 0.25 M K₂SnO₃ solution for 30 min. The as-fabricated SnO₂/TNHAs were utilized as the efficient-photoanodes for DSSCs. The SnO₂ nanoparticles have a superior light harvesting capability owe to the higher upper-surface area for maximum dye-uploading and the high electron-mobility. The SnO₂/TNHAs based DSSC had a PCE of 6.43%, which was 1.34 fold higher than those of pure TNHAs. Furthermore, IPCE and the amount of dye adsorption were also improved.