Bifunctional barium cobalt sulfide (BCS) spherical like structure composites with and without carbon materials (MWCNT and GQDs) are synthesized via hydrothermal method and are used as a counter electrode (CE) for DSSC and working electrode for supercapacitors. Crystalline structure, shape and chemical state of the prepared samples are examined by XRD, SEM, TEM and XPS analysis. BCS/MWCNT/GQDs CE based device delivers the short circuit current (JSC) of 10.57 mA/cm2 and open circuit voltage (VOC) of 0.73 V and Fill Factor (FF) of 0.58 and Power Conversion Efficiency (PCE) of 4.48%, which shows two-fold increment than pristine BCS CE. The same composites are tested under cyclic voltammetry and charge/discharge characteristic due to analyze the charge storage performance. Among the three composites, the GQDs embedded BCS/MWCNT composite exhibits the highest specific capacitance of 191 C/g. The findings show that GQDs supported BCS/MWCNT composites are not only a feasible option for Pt-free counter electrodes, but also provide a better outlook for energy storage devices.
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