Bi2S3-sensitized TiO2 nanorods by bottom-up approach for photoelectrochemical solar cell

Bismuth sulfide (Bi2S3)-sensitized titanium dioxide (TiO2) nanorods have been successfully synthesized by a simple and cost-effective chemical deposition method onto the conducting glass substrates. Bi2S3 nanoparticles are sensitized over the hydrothermally grown TiO2 nanorods by using successive ionic layer adsorption and reaction (SILAR) method. The structural, morphological, optical, and electrochemical studies were carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible–near infrared (UV–Vis–NIR) spectroscopy, electrochemical impedance spectroscopy (EIS), etc. XRD pattern reveals the formation of pure rutile tetragonal TiO2 with orthorhombic Bi2S3 crystal structure. SEM images show the formation of Bi2S3-sensitized TiO2 nanorods. The diameter of the nanorods is ~ 250 nm, and the size of Bi2S3 nanoparticles is ~ 100 nm. The films show hydrophilic nature which is beneficial for the photoelectrochemical performance of the photoanodes. The optimized photoanode shows an improved short-circuit photocurrent density of 421 µA/cm2 with a power conversion efficiency of 0.06% in polysulfide electrolyte.