Performance enhancement for quasi-solid-state dye-sensitized solar cells by using acid-oxidized carbon nanotube-based gel electrolytes

Quasi-solid-state ionic liquid (IL) gel electrolytes for dye-sensitized solar cells (DSSCs) are prepared via dispersion of multi-wall carbon nanotubes (MWCNTs) in room temperature ILs. Addition of MWCNTs significantly increases the viscosity as well as the conductivity of MWCNT-based IL gels. Compared with raw MWCNTs, acid-oxidized MWCNTs improve the miscibility with ILs, which results in an enhanced gel-forming ability of MWCNT/IL gels. The solar cells based on acid-oxidized MWCNT/IL gel electrolytes yield the power conversion efficiency of 5.74% under the simulated air mass 1.5 solar spectrum illumination at 100 mW cm−2. The superior long-term stability of fabricated DSSCs indicates that the cells based on acid-oxidized MWCNT/IL gel electrolyte could overcome the drawbacks of volatile liquid electrolytes.