Nanocrystalline TiO2 sensitized with CdS quantum dots for photoelectrochemical study

CdS quantum dots sensitized TiO2 nanocrystalline photoanode was developed on conducting FTO substrates which act as working electrode in photoelectrochemical cells. Deposition process was conducted by applying ionic layer adsorption and SILAR process. The thickness of CdS quantum dots (QDs) are maintained by cycles of SILAR. The morphology and nature of TiO2/CdS photoanodes are characterized by XRD, UV-Vis., IR, PL, TEM and EDS analysis. XRD patterns indicate the presence of anatase TiO2 and CdS in TiO2/CdS quantum dots thin film (5 and 10 cycles) samples with crystallite size 11.19 nm. The optical band gap energies are 3.10, 3.05 and 2.78 eV for TiO2, TiO2/CdS quantum dots (5 and 10 cycles), respectively. The band gap energy of TiO2 found to be decreases with the sensitization of CdS quantum dots. The images of HR-TEM confirm the formation of a heterostructure between TiO2 and CdS quantum dots. The PEC performance for TiO2/CdS photoanode was analyzed using a 500 W tungsten lamp with light intensity of 30 mW/cm(2) in the electrolyte iodide/polyiodide as a redox couple (0.5 M). CdS quantum dots sensitized TiO2 film as a photoanode for solar cells produces good power conversion efficiency of 1.32 and 3.52% for 5 and 10 cycles respectively.

Automated summary

A CdS quantum dots sensitized TiO2 nanocrystalline photoanode was developed on conducting FTO substrates, which served as the working electrode in photoelectrochemical cells. The CdS quantum dots thickness was controlled by cycles of the SILAR process. The TiO2/CdS photoanodes were analyzed and characterized using various techniques. The PEC performance of the TiO2/CdS photoanode showed good power conversion efficiency, reaching 1.32% and 3.52% for 5 and 10 cycles, respectively.