Photosensitization of TiO2 nanorods with CdS quantum dots for photovoltaic applications: A wet-chemical approach

We combine CdS semiconductor quantum dots and single-crystalline rutile TiO 2 nanorod arrays to produce a practical quantum dot sensitized solar cell . A facile wet-chemical approach was implemented for growth of this CdS@TiO 2 architecture. Rutile TiO 2 nanorod arrays with lengths of 1–2   μm and diameters of 40–60   nm were synthesized on fluorine-doped tin oxide glass by a hydrothermal process in a titanium tetrachloride precursor solution . CdS quantum dots with a size of 5–10   nm were deposited onto a TiO 2 nanorod surface using an ultrasonic-assisted chemical bath deposition method . The resulting CdS quantum dots and TiO 2 nanorods formed a type-II heterojunction and showed increased absorption over visible light range. Incident photon-to-current conversion efficiencies (IPCE) as high as 85% and power conversion efficiencies of 2.54% were obtained using a polysulfide electrolyte.