Caracterization of ZnO thin film/electrolyte interface via electrochemical impedance measurments

In this study, we determine the methodology employed for extracting compounds from Sidr-plant leaves to synthesize Zinc Oxide ($\mathbf{Z n O}$) thin films fabricated via spray pyrolysis and explore the structural, morphological, and electrical properties. Atomic Force Microscopy (AFM) examination illustrated a uniform dispersion of ZnO thin film throughout the $\mathbf{Z n O}$ electrode surface. Scanning Electron Microscopy (SEM) investigations unveiled microporous architecture within the ZnO thin film, with dimensions ranging from $1.851 \mu \mathrm{~m}$ to $6.638 \mu \mathrm{~m}$. Additionally, ZnO thin film deposited onto copper substrate underwent testing for electrochemical performance in a 0.1 M KCl electrolyte solution. The interface has been modeled as an equivalent circuit consisting of a parallel charge transfer resistance $R_{c t}$ and a constant phase element (CPE) in series with a resistance of electrolyte Rs. Through capacitance measurements and Mott-Schottky analysis, we scrutinized the semiconductor-electrolyte interfaces by varying applied de potential and frequency. Moreover, the carrier concentrations N<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</inf> and flat band potentials $V_{f b}$ of the sample were obtained by Mott-Schottky analysis.