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

•Electrochemical exfoliation graphene modified by repeated ultrasonication.•Repeated ultrasonication improves the dispersion ability and structural defects.•Six repetitions of ultrasonication leads to a higher performance counter electrode. 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 ultrasonication 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. [Display omitted]