Branched Bi₂S₃/TiO₂ nano-heterostructure with enhanced photoelectric performance

The fabrication of a branched nano-heterostructure composed of Bi₂S₃ nanosheet branches and TiO₂ nanorod stem was performed using a facile and cost-effective hydrothermal method. The nanoscale morphology of Bi₂S₃ deposited on TiO₂ nanorod arrays was regulated by controlling the hydrothermal growth time of Bi₂S₃ sensitizer. The optical properties and photoelectrochemical performance were evaluated systematically for Bi₂S₃/TiO₂ heterostructures with different morphology. The Bi₂S₃/TiO₂ heterostructures presented the higher visible-light absorption ability and photoelectric performance compared to the bare TiO₂. The highest photocurrent density of approximately 6.01 mA cm⁻² was obtained for the Bi₂S₃/TiO₂ heterostructure with 1 h hydrothermal sensitization time. The improved photoelectric performance was attributed to the unique branched structure resulting in an obviously enhanced light absorption in visible-light region and better electron-hole separation and transporation. (paper)