Modification of carbon nanotubes with 4-mercaptobenzoic acid-doped polyaniline for quantum dot sensitized solar cells

Polyaniline (PANI) was grafted onto multi-walled carbon nanotubes (MWCNT) in order to increase the number of reactive groups on the MWCNT. The PANI was subsequently doped with 4-mercaptobenzoic acid providing coordinating sites to adsorb a quantitative amount of quantum dots (QDs). Treating such a modified MWCNT in a suspension of QDs, a MWCNT-based composite was obtained and employed as an electrode in a solar cell. The composite was denoted as MWCNT@PANI-SH@QDs, and the solar cell studied in this paper was denoted as a QDs sensitized solar cell (QDSSC). It was found that excited electrons from the QDs were effectively transferred to MWCNT with minimal energy loss via phonon formation and photon recombination. As a result, the power conversion efficiency of the QDSSC reached 3.76% under AM 1.5 illumination.