Dye sensitized solar cell with lawsone dye using a ZnO photoanode: experimental and TD-DFT study

Abstract

The spectral features of lawsone (2-hydroxy-1,4-naphthoquinone), an active component of the natural dye henna, are analyzed in ethanol using experimental and computational methods. The calculated UV-Vis absorption spectrum from the time-dependent density functional theory (TD-DFT) approach is compared with the experimental results, allowing a detailed assignment of the UV-Vis spectral features based on molecular orbitals. Further, we have analyzed the light intensity dependent J–V characteristics and electrochemical impedance spectrum of a dye sensitized solar cell fabricated with lawsone and a ZnO photoanode. The photovoltaic data of the sensitizer adsorbed on ZnO films exhibited a reasonable power conversion efficiency, i.e. 0.68% at 26 mW cm⁻² light intensity.