Ultrasonication-modified electrochemically exfoliated graphene for counter electrode in dye-sensitized solar cells

Graphene has various excellent properties, contributing to its wide potential applications. Electrochemically exfoliated graphene (EEG) is a graphene-like material synthesized via electrochemical methods, requiring a shorter synthesis time and much less chemical waste than the Hummers method. Ultrasonication modification of EEG will increase the structure of defects, dispersion capability, and performance of EEG as a counter electrode (CE) material in dye-sensitized solar cells (DSSC). FTIR-ATR, XRD, and Raman spectroscopy confirmed the EEG material. SEM-EDS analysis observed that all EEGs have thick layer morphology. The dispersion study showed that repeated ultrasonication improves the dispersion ability of the EEG material. In addition, repeated ultra-sonication improves the structural defects in EEG material. The EEG with 6 repetitions of sonication (EEG_6) gave the highest performance as a CE in DSSC with 0.890% efficiency, while the reduced graphene oxide (rGO) with the Hummers method is 0.714%. When the mixture of Polyaniline/Graphite/EEG_6 (PG_EEG_6) material was used as a CE, a 2.493% efficiency was gained, better than Pt CE (1.626%). Therefore, using EEG_6 composite as a CE leads to a higher-performing and more eco-friendly DSSC.