Fabrication and performance analysis of a low cost, Pt free counter electrode using carbon coated ZnAl layered double hydroxide (C/ZnAl-LDH) for dye sensitized solar cells

Abstract

Carbon based material represents an effective substitute for Pt counter electrodes (CEs) in Dye Sensitized Solar Cells (DSSCs). This study introduces a novel carbon coated ZnAl layered double hydroxides (C/ZnAl-LDH) can be utilised as an effective CE in DSSCs. C/ZnAl-LDH was synthesised by the pyrolysis of ZnAl-LDH using glucose solution. The synthesised C/ZnAl-LDH was characterised using TEM, SEM, XRD and BET analysis. The surface roughness of both Pt and C/ZnAl-LDH films were analysed using AFM spectroscopy. C/ZnAl-LDH slurry was pasted uniformly using doctor blade technique onto FTO glass substrate. The electrochemical measurements such as Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and Tafel polarization recommends that C/ZnAl-LDH can be used as a CE due to its good reduction rate of I3- comparable with Pt CEs. The photovoltaic parameters were observed to be 0.66 V and 11.97 mA/cm2 for open circuit voltage (Voc) and short circuit current density (Jsc) respectively for C/ZnAl-LDH CE. The assembled cell with C/ZnAl LDH CE having power conversion efficiency (PCE) of 3.18% is comparable to Pt CE having 4.62% which is measured under the similar testing conditions.