title: Size selective photoetching of CdSe quantum dot sensitizers on single-crystal TiO₂.
abstract: Cadmium selenide quantum dots covalently attached to and photosensitizing single-crystal TiO2 surfaces are observed to corrode under illumination in aqueous electrolyte containing iodide as a regenerator. Comparison of photocurrent spectra before and after long-term monochromatic illumination indicated that the CdSe QD sensitizers photocorroded and decreased in size until their band gap energy exceeded the excitation energy. This wavelength-dependent photoelectrochemical etching mechanism can be used to tune the size distribution of surface adsorbed QDs and may account for the instability of QD sensitized solar cells that do not employ sulfide-based electrolytes.
authors.affiliation: Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States.
authors.forename: Justin B
authors.initials: JB
authors.lastname: Sambur
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Parkinson
keywords: corrosion; quantum dot sensitized solar cells (QDSSCs); quantum dots (QDs); single-crystal TiO2; size-selective etching; stability