Characterization of the contact between TiO/sub 2/ and PbS quantum dots

The synthetic procedure of the growth of one semiconductor material (PbS) on a seed of another (TiO/sub 2/) have been developed. The contact between TiO/sub 2/ and PbS quantum dots was characterized by optical absorption and fluorescence. The dramatic increase of the bandgap of PbS (/spl Delta/E/sub g/=1.5 eV) was observed after precipitation of PbS in the colloidal solution of TiO/sub 2/. The positions of the lowest empty energy level of TiO/sub 2/ and PbS single quantum dots as well as TiO/sub 2/-PbS composite were determined by a pulse radiolysis technique. The contact between TiO/sub 2/ and PbS quantum dots leads to the transfer of electrons from PbS to TiO/sub 2/.