Study of photoelectrochemical (PEC) solar cell properties of n-type bismuth sulfide (n-Bi₂S₃)/p-type copper (I) iodide (p-CuI) heterojunction synthesized by SILAR

Photoelectrochemical (PEC) solar cell properties of the synthesized n-type bismuth sulfide (n-Bi₂S₃)/p-type copper (I) iodide (p-CuI) heterojunction using an easy approach of successive layer adsorption and reaction have been studied. X-ray diffraction (XRD) was used to give an insight of the structures, morphological study was carried out in a scanning electron microscopy (SEM), and the band gap was studied in an ultraviolet–visible spectroscopy. Photoluminescence (PL) analysis was also carried out, and contact angle was measured to understand the interaction of film surface and liquid. Bi₂S₃ exhibits a zinc blende face-centered cubic (FCC) structure and CuI shows an orthorhombic phase, whereas the optical band gap of n-Bi2S3/p-CuI is found to be 2.84 eV. The surface for CuI crystallites shows a tetrahedral form, sharp edges, and a good substrate coating but interlocked nanoparticles with nanoporosity being discovered for Bi₂S₃. With increasing SILAR cycles, the power conversion efficiency was improved, according to the current density to voltage (J–V) analysis. The power conversion efficiency for 50 SILAR cycles is 1.33%, which is noticeable when compared to 30 and 40 SILAR cycles.