title: Photosensitization of ZnO nanowires with CdSe quantum dots for photovoltaic devices.
abstract: We combine CdSe semiconductor nanocrystals (or quantum dots) and single-crystal ZnO nanowires to demonstrate a new type of quantum-dot-sensitized solar cell. An array of ZnO nanowires was grown vertically from a fluorine-doped tin oxide conducting substrate. CdSe quantum dots, capped with mercaptopropionic acid, were attached to the surface of the nanowires. When illuminated with visible light, the excited CdSe quantum dots injected electrons across the quantum dot-nanowire interface. The morphology of the nanowires then provided the photoinjected electrons with a direct electrical pathway to the photoanode. With a liquid electrolyte as the hole transport medium, quantum-dot-sensitized nanowire solar cells exhibited short-circuit currents ranging from 1 to 2 mA/cm2 and open-circuit voltages of 0.5-0.6 V when illuminated with 100 mW/cm2 simulated AM1.5 spectrum. Internal quantum efficiencies as high as 50-60% were also obtained.
authors.affiliation: Department of Chemical Engineering & Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, USA.
authors.forename: Kurtis S
authors.initials: KS
authors.lastname: Leschkies
authors.forename: Ramachandran
authors.initials: R
authors.lastname: Divakar
authors.forename: Joysurya
authors.initials: J
authors.lastname: Basu
authors.forename: Emil
authors.initials: E
authors.lastname: Enache-Pommer
authors.forename: Janice E
authors.initials: JE
authors.lastname: Boercker
authors.forename: C Barry
authors.initials: CB
authors.lastname: Carter
authors.forename: Uwe R
authors.initials: UR
authors.lastname: Kortshagen
authors.forename: David J
authors.initials: DJ
authors.lastname: Norris
authors.forename: Eray S
authors.initials: ES
authors.lastname: Aydil
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry* / Q000528:radiation effects; D011211:Electric Power Supplies; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods; D043942:Nanotubes / Q000737:chemistry* / Q000528:radiation effects / Q000648:ultrastructure; D010777:Photochemistry / Q000295:instrumentation / Q000379:methods*; D045663:Quantum Dots; D013440:Sulfides / Q000737:chemistry* / Q000528:radiation effects; D015034:Zinc Oxide / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D019187:Cadmium Compounds; D013440:Sulfides; C034939:cadmium sulfide; D015034:Zinc Oxide