Influence of ZnO/MWCNTs based hybrid electrodes for boosting the performance of photovoltaic and supercapacitor devices

In this work, multi-wall carbon nanotubes (MWCNTs with 1, 3 and 5 wt.%) are mixed with zinc oxide (ZnO) to prepare nanocomposites for energy conversion and storage applications. Further, UV–Vis spectra of synthesized pure ZnO and ZnO/MWCNTs nanocomposite material shows enhanced light absorption in the visible region. Hexagonal wurtzite crystal structure of the nanocomposites is confirmed by X-ray diffraction (XRD) spectra. Field emission scanning electron microscopy (FE-SEM) and High resolution-transmission electron microscopy (HR-TEM) images explores the formation of nanocomposite with flake like ZnO and tube structured MWCNTs at nanoscale region. Dye sensitized solar cells (DSSC) are constructed with pure and nanocomposite material as photoanode and the effect of addition of MWCNTs on the performance of solar cells are studied. Further, the cyclic voltammetry (CV), galvanic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) are employed to examine the electrochemical characteristics of the prepared electrode in a 1 M Na2SO4 electrolyte. In three electrode configuration, the CV and GDC curves exhibits good reversibility and attains a specific capacitance value of 115.7 F g−1 with the addition of MWCNTs onto the ZnO. Also, the asymmetric supercapacitor device exhibits the improved storage performance. The EIS spectra shows lowest Rs and Rct resistance, indicating the prepared electrode is favorable for DSSC and supercapacitor application.