Electrochemical Impedance Spectroscopy Characterization of a Bismuth Oxyiodide (BiOI) Electrochemical Cell in Terms of Various Morphologies

This investigation reports the electrochemical impedance spectroscopy (EIS) characterization of dip-successive ionic layer adsorption and reaction (SILAR)-prepared BiOI electrochemical cells in terms of various morphologies. Here, the photocathode BiOI has been prepared at various cycle numbers, which causes a change in the surface morphology that is observed by field emission scanning electron microscopy (FESEM). The increasing cycle number until 30 brings the change in the BiOI film's flaky structures, crystal size, and effective surface area. At 30-dip-SILAR cycle, the film's uniformity of flaky structure and effective surface area reach their maximum values, resulting in the lowest film resistance and lowest charge transfer resistance (at the BiOI-electrolyte interface) recorded via EIS analysis. Hence, at 30 cycles (thickness 500 nm), the maximum photovoltaic performance has been observed: short-circuit current density J(SC) = 0.6 mA/cm(2), and open-circuit voltage V-OC = 0.43 V. [GRAPHICS] .

Automated summary

The investigation characterized BiOI electrochemical cells prepared by successive ionic layer adsorption and reaction (SILAR) through electrochemical impedance spectroscopy (EIS). The study found that at 30 SILAR cycles, the BiOI film exhibited the best structural uniformity and effective surface area, resulting in the lowest film resistance and charge transfer resistance, leading to maximum photovoltaic performance with a short-circuit current density of 0.6 mA/cm(2) and open-circuit voltage of 0.43 V.