Application of non-covalent functionalized carbon nanotubes for the counter electrode of dye-sensitized solar cells

Abstract Multi-walled carbon nanotubes (MWCNTs) were functionalized noncovalently by lysozyme (LZ), cetyl pyridinium chloride (CPC), deoxycholate sodium (NaDC) and polyethylene glycol octylphenol ether (Triton X-100), respectively in this study. Four different kinds of functionalized MWCNTs were employed into dye-sensitized solar cell (DSSC) as the Pt-free counter electrode (CE). The correlation between the dispersion of MWCNTs and electrochemical active area of CE and the photovoltaic characteristic of DSSC were investigated. Among these four DSSCs, the one with Triton X-100 functionalized MWCNTs showed the best energy conversion efficiency of 2.69% which is 11.16% higher than the DSSC using pristine MWCNTs CE (2.42%), yet the efficiency is lower than the DSSC using Pt CE. While the DSSC with CPC, NaDC and LZ functionalized MWCNTs as the CE showed inferior the photovoltaic conversion efficiency than the DSSC using pristine MWCNTs CE. On analysis of the photovoltaic performance of DSSC and the dispersion of MWCNTs and electrochemical active area of CE, it is found that the high efficiency of the DSSC is associated with the good dispersion of MWCNTs and large electrochemical active area of the counter electrode material.