Economical Dye-sensitized Solar Cells Based on Polypyrrole/ Multiwalled Carbon Nanotube@Reduced Graphene Oxide Nanoribbon Counter Electrode

Abstract

Pyrrole (Py) polymerized on multiwalled carbon nanotube@reduced graphene nanoribbon (MWCNT@rGNR) was reported as an efficient counter electrode (CE) for dye-sensitized solar cell (DSSC). Field-emission scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) showed the microstructure detail of PPy/MWCNT@rGNR composite with the dense and flat pristine PPy film deposited on graphene sheet covering on a MWCNT and Raman spectroscopy were used to further confirm the formation of reduced graphene nanosheets and the degree of defect on the surface of PPy/MWCNT@rGNR composite. Cyclic voltammetry (CV) was used to study the electrocatalytic activities of the films of MWCNT, GONR, rGNR, PPy, and PPy/MWCNT@rGNR. The CV measurement revealed that resultant composites exhibited a superior electrocatalytic performance for tri-iodide reduction in the order of PPy/MWCNT@rGNR > rGNR > GONR > MWCNT > PPy. The efficiency of a solar cell with PPy/MWCNT@rGNR CE was superior to those with the other CEs. Such excellent electrocatalytic ability for the reduction of I3–ions can be attributed to the fact that PPy has high conductivity and superior electrocatalytic activity as well as rGNR has high electron transfer, surface roughness, and surface area to promote the reduction and regeneration of I3–ions.