Synthesis and characterization of temperature-dependent nanospherical Cu_2−xSe thin films for photoelectrochemical cell application

In this investigation, copper selenide (Cu_2−xSe, x = 0.57) thin films were synthesized employing the environmentally benign self-organized arrested precipitation technique (APT) on the soda-lime glass (SLG) as well as on tin-doped indium oxide (ITO) substrates, varying deposition temperatures of 40 °C, 55 °C, 70 °C. Characterization, encompassing UV–Vis spectrophotometry, X-ray diffraction (XRD), and scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS). The results elucidated distinctive attributes of the thin films, having a notably visible light absorption profile in the range of 600–700 nm for all samples and characterized by bandgap energy of 1.59 eV for the sample at 70 °C. The manifestation of a singularly phase-pure cubic crystal structure for temperature of 70 °C and hexagonal for 45 °C and 55 °C temperatures, and the emergence of nanospherical surface morphology. Significantly, the Cu_2−xSe thin films evinced augmented photoelectrochemical (PEC) proficiency, prolonged stability in PEC environments, and exhibited consistent p-type conductivity. Underscoring their prospective utility in energy conversion, particularly in the context of photoelectrochemical cells.