“…Sensitization of wide band-gap semiconductors, for example TiO 2 , ZnO and SnO 2 , by the QDs is one of the most advantageous structures for solar-energy conversion devices [11,17,21,23,24,30,31]. Figure 9.3 shows a photograph of a CdS QD-sensitized TiO 2 nanocrystalline film (size: 5 Â 5 mm 2 ).…”