Flexible and novel counter electrode from graphene/Zn Al layered double hydroxide nanocomposite in dye sensitized solar cells

Abstract

• G/ZnAl-LDH composite was firstly applied as a CE in DSSC. • The specific capacitance was calculated at 470.2 Fg −1 . • PCE of G/ZnAl-LDH CE was 4.4% which is comparable to GO CE having 3.7%. • PCE was decreased only to 95% of its initial value after week. Due to their simplicity of manufacture, superior corrosion resistance, and low cost compared to platinum (Pt) electrodes, carbon-based counter electrodes (CE) of dye-sensitized solar cells (DSSCs), such as graphene composite (G), have attracted unprecedented interest in recent years. However, poor surface adhesion between the carbon counter electrodes (CCE) and the FTO substrate, as well as limited surface area and poor inter-particle connectivity between the carbon materials, have continuously proven to be a significant problem. To avoid these issues, we used a hydrothermal technique to fabricate G/Zn-Al-LDH as CE in DSSCs. The conversion of triiodide to iodide utilizing electrons flowing through an external circuit relies on CE so CE plays a crucial role in DSSCs. Enhancing the power conversion efficiency (PCE) and lowering the device's cost are two efficient ways to increase the performance of a CE. The prepared G/Zn-Al-LDH was investigated by X-ray diffraction (XRD), Raman spectroscopy, High-Resolution Transmission Electron Microscopy (HRTEM), Scanning electron microscope (SEM), surface area Fourier Transform infrared spectroscopy (FTIR), Electrochemical impedance spectroscopy (EIS), Cyclic voltammetry (CV) and Tafel polarization test. G/Zn-Al-LDH was used as novel CE in DSSCs with TiO 2 nanoparticles (T NP ) as a working electrode, Eosin Y (EY) as photosensitizer, and LiI-I 2 as a liquid electrolyte. The photovoltaic parameters were observed to be 0.66 V and 11.23 mA/cm 2 for open circuit voltage (V OC ) and short circuit current density (J SC ), respectively for T NP /EY/LiI-I 2 /G/ZnAl-LDH system. The assembled cell with T NP /EY/LiI-I 2 /G/ZnAl-LDH having (PCE) of 4.4 % is comparable to T NP /EY/LiI-I 2 /GO having 3.7 % which is measured under similar testing conditions.