Dye-sensitized solar cells based on multiwalled carbon nanotube–titania/titania bilayer structure photoelectrode

Abstract

Dye-sensitized solar cells (DSSCs) were fabricated using multiwalled carbon nanotube (MWCNT)–TiO 2 nanocomposite as a light scattering layer. Morphology of the MWCNT–TiO 2 film was investigated by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). FESEM and TEM images demonstrate that MWCNTs and TiO 2 nanoparticles can be dispersed with chitosan. Internal resistance in the DSSC was characterized by electrochemical impedance spectroscopy (EIS). EIS results reveal a decrease in the charge resistance of electrolyte/dye/MWCNT–TiO 2/TiO 2 interface with increasing MWCNT content up to 3 wt% which leads to an improvement in the photovoltaic performance. Compare with a nanocrystalline TiO 2 single-layer cell, the DSSC based on the MWCNT (3 wt%)–TiO 2/TiO 2 bilayer structure photoelectrode shows ∼100% increase in solar-to-electric energy conversion efficiency, which is attributed to the inclusion of MWCNTs in TiO 2 matrix.