OICC Press Anthropogenic Pollution 2588-4646 10 1 2026 06 30 Electrodeposited CdS Nanostructured Thin Films as a Photoelectrochemical Sensor for Monitoring Pb(II) in Aquatic Environments 10.57647/AP.2026.1001.12 EN Zahra Ghalandari Ghojlu Department of Physics, Mah.C., Islamic Azad University, Mahabad, Iran Nasim Nobari Department of Physics, Mah.C., Islamic Azad University, Mahabad, Iran Mahdi Behboudnia Department of Physics, Urmia University of Technology, P.O. Box 57155-419, Urmia, Iran Journal Article 2026 06 30 Nanostructured CdS thin films were fabricated on FTO substrates by electrodeposition for the photoelectrochemical detection of Pb (II) ions in water. The CdS films were deposited at an applied potential of 830 mV for 6 min, producing uniform nanostructured coatings on the conductive substrate. The structural, morphological, and compositional characteristics of the films were systematically investigated using X ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X ray spectroscopy (EDS). XRD analysis confirmed the formation of polycrystalline CdS with well-defined diffraction peaks corresponding to the CdS phase. SEM observations revealed a homogeneous nanostructured surface composed of closely packed grains with an average size of approximately 40 nm, providing a high surface area beneficial for sensing applications. EDS spectra verified the presence of Cd and S as the dominant elements, indicating the successful formation of CdS without detectable impurity phases. Optical characterization indicated a band gap energy of approximately 3.3 eV, demonstrating suitable photoactive behavior under visible light illumination. The photoelectrochemical sensing performance of the CdS thin films toward Pb (II) ions was evaluated in the concentration range of 1–20 ppm under periodic illumination (10 s light/dark cycles). The photocurrent response increased linearly with increasing Pb (II) concentration, following the calibration relationship: I(μA) = 0.42C + 0.19 The stronger sensing response is mainly due to the nanostructured CdS surface, which helps separate charges more efficiently and offers more sites for Pb (II) to bind. Overall, electrodeposited CdS films provide a simple, affordable, and effective way to detect Pb (II) in water.