Improved Photovoltaic Properties of Nano-Flake-Based Mesoporous Dip- SILAR Prepared BiOI Electrochemical Cell By Tuning Post-Annealing Treatment Time at 100°C

Background: This research article reports on the post-annealing treatment time effect on the dip-successive ionic layer adsorption and reaction (SILAR) prepared nano-flake-based mesoporous BiOI electrochemical cell's photovoltaic properties. Objective: Our study clarifies that the post-annealing time has a great impact on the photovoltaic behavior and the nano-flake morphology. Methods: At 100°C for 90 mins of post-annealing treatment conditions, the surface morphology converted into a connected uniform crystallized flaky structure, which improves the effective surface area and reduces the BiOI/electrolyte charge transfer resistance confirmed via electrochemical impedance spectroscopy (EIS) analysis. Therefore, the maximum photovoltaic properties (short-circuit current density, Jsc = 1.83mA/cm², open-circuit voltage, Voc = 0.48V and efficiency = 0.28%) have been observed. However, without annealing and beyond 90 mins of post-annealing time, the film quality and crystallinity decreased as a consequence of photovoltaic properties degradation. Results and Conclusion: Our investigation finding is that 90 mins is the optimal post-annealing treatment duration for the dip-SILAR prepared nano-flake-based mesoporous BiOI electrochemical photovoltaic cell at 100°C post-annealing temperature.