A free radical assisted strategy for preparing ultra-small Pt decorated CNTs as a highly efficient counter electrode for dye-sensitized solar cells

In this paper, a free radical assisted strategy was introduced into the functionalization of counter electrodematerials for the first time. With the assistance of a radical initiator, short-chained thiol groups can be attached on a multi-walled carbon nanotube (MWCNT) surface covalently, which was confirmed to be beneficial for both controlling the particle growth of platinum (Pt) on MWCNTs and improving the electron transfer between counter electrode materials and the substrate. The obtained Pt-MWCNT composite has been applied as a counter electrode material for dye-sensitized solar cells, and the power conversion efficiency (eta) was detected to be 8.62%, surpassing that of the cell with a conventional Pt counter electrode (eta = 7.56%). Especially, the fill factor improved considerably from 0.57 to 0.65.