Pioneering an Innovative Eco-Friendly N719 Dye-Sensitized Solar Cell through Modelling and Impedance Spectroscopy Analysis for Energy Sustainability

Dye-sensitized solar cells (DSSC) have received significant interest in the photovoltaic technology because of their eco-friendly nature, affordability and flexibility. Here, this work presents a DSSC of the configuration; FTO/WO₃/N719 Dye/GO/C with performance metrics – open-circuit voltage (V_oc) of 1.1055 V, short-circuit current density (J_sc) of 22.23 mA cm⁻², a fill factor (FF) of 84.65%, and a remarkable power conversion efficiency (PCE) of 20.80%. The study utilizes a wide frequency range of 10⁻³ to 10¹⁰ Hz to examine charge transport dynamics and evaluate the electrochemical performance of the model cell. Impedance spectroscopy investigates both complex electrical impedance (Z*) and electric modulus (M*) to provide critical insights into ionic transport, charge recombination, ion migration and diffusion mechanisms within the cell. A model equivalent circuit is developed and theoretically validated by fitting experimental alternating current (AC) data to theoretical predictions, allowing the extraction of characteristic time constants for various processes. The results highlight that efficient ion conduction and rapid electron diffusion are essential for optimizing charge collection and minimizing recombination losses. Further, the study emphasizes the critical role of both series and shunt resistances across low- and high-frequency domains, establishing a strong correlation between time constant behavior and overall device efficiency.