Impact of light intensity on CdSe thin-film electrodes deposited by CBD over a prepared ED CdSe primary layer

This paper reports the effect of light intensity on the performance of PEC solar cells using CdSe thin films deposited via a combined electrodeposition (ED) and chemical bath deposition (CBD) technique. The ED method produced a thinner primary layer with excellent adhesion to FTO but insufficient photon absorption, whereas the subsequent CBD layer increased in thickness, enabling better photon absorption and greater photocurrent generation. The optical and structural properties of the films under consideration were calculated from the results of UV‒Vis spectroscopy, XRD, and SEM. J–V characterization at light intensities of 0.0025, 0.005, 0.010, and 0.020 W/cm² indicated that increasing the light intensity increased the photocurrent and decreased the quantum yield efficiency. The dependence of the photocurrent on light intensity reflects a logarithmic increase whereby higher intensities generate many electron‒hole pairs, hence increasing the photocurrent. However, the quantum yield efficiency decreases logarithmically as the light intensity increases due to recombination losses. This inverse logarithmic relationship shows that the light conditions are optimized so that a balanced photocurrent and efficiency can be obtained to maximize the performance of solar cells. The parameters that could influence the optimization of PEC solar cells include the size of the particles and the deposition technique. Obviously, the conjoined CBD/ED method could produce smaller particles with higher efficiency. These results are part of the development of technologies for efficient and stable solar energy conversion.