title: Electron injection from colloidal PbS quantum dots into titanium dioxide nanoparticles.
abstract: Injection of photoexcited electrons from colloidal PbS quantum dots into TiO(2) nanoparticles is investigated. The electron affinity and ionization potential of PbS quantum dots, inferred from cyclic voltammetry measurements, show strong size dependence due to quantum confinement. On the basis of the measured energy levels, photoexcited electrons should transfer efficiently from the quantum dots into TiO(2) only for quantum-dot diameter below approximately 4.3 nm. Continuous-wave fluorescence spectra and fluorescence transients of PbS quantum dots coupled to titanium dioxide nanoparticles are consistent with electron transfer for small quantum dots. The measured electron transfer time is surprisingly slow ( approximately 100 ns), and implications of this for future photovoltaics will be discussed. Initial results obtained from solar cells sensitized with PbS quantum dots are presented.
authors.affiliation: Department of Applied Physics, Cornell University, Ithaca, New York 14850, USA. bh73@cornell.edu
authors.forename: Byung-Ryool
authors.initials: BR
authors.lastname: Hyun
authors.forename: Yu-Wu
authors.initials: YW
authors.lastname: Zhong
authors.forename: Adam C
authors.initials: AC
authors.lastname: Bartnik
authors.forename: Liangfeng
authors.initials: L
authors.lastname: Sun
authors.forename: Hector D
authors.initials: HD
authors.lastname: Abruña
authors.forename: Frank W
authors.initials: FW
authors.lastname: Wise
authors.forename: Jason D
authors.initials: JD
authors.lastname: Goodreau
authors.forename: James R
authors.initials: JR
authors.lastname: Matthews
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Leslie
authors.forename: Nicholas F
authors.initials: NF
authors.lastname: Borrelli
mesh_terms: D003102:Colloids / Q000737:chemistry*; D004583:Electrons; D008027:Light; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D009991:Oscillometry; D010777:Photochemistry; D045663:Quantum Dots; D012666:Semiconductors; D013050:Spectrometry, Fluorescence / Q000379:methods; D014025:Titanium / Q000737:chemistry*
chemical_list: D003102:Colloids; C009495:titanium dioxide; D014025:Titanium