CdS Quantum Dots Sensitized TiO₂ Nanotube-Array Photoelectrodes

Novel CdS quantum dots (QDs) sensitized TiO₂ nanotube-array photoelectrodes were investigated for their photoelectrochemical (PEC) performance. The highly ordered TiO₂ nanotube arrays were synthesized by anodic oxidation and CdS QDs were deposited into the pores of the nanotube arrays by a sequential chemical bath deposition method. It is found that the CdS QDs deposited in the pores of the TiO₂ nanotube arrays may significantly increase the liquid junction PEC short circuit photocurrent (from 0.22 to 7.82 mA/cm²) and cell efficiency (up to 4.15%). These results clearly demonstrate that the unique nanotube structure can facilitate the propagation and kinetic separation of photogenerated charges, suggesting potentially important applications of the inorganic QDs sensitized TiO₂ nanotube-array films in solar cell applications.