title: Size-dependent electron transfer from PbSe quantum dots to SnO2 monitored by picosecond Terahertz spectroscopy.
abstract: We report the direct and unambiguous determination of electron transfer rates and efficiencies from PbSe quantum dots (QDs) to mesoporous SnO2 films. We monitor the time-dependent electron density within the oxide with picosecond time resolution using Terahertz spectroscopy, following optical excitation of the QDs using a femtosecond laser pulse. QD-oxide electron transfer occurs with efficiencies of ∼2% in our samples under 800 nm pumping with a marked dependence on QD size, ranging from ∼100 ps injection times for the smallest, ∼2 nm diameter QDs, to ∼1 ns time scale for ∼7 nm QDs. The size-dependent electron transfer rates are modeled within the framework of Marcus theory and the implications of the results for device design are discussed.
authors: FOM Institute for Atomic and Molecular Physics, Science Park 104, 1098 XG Amsterdam, The Netherlands. canovas@amolf.nl
authors: Enrique
authors: E
authors: Cánovas
authors: Puck
authors: P
authors: Moll
authors: Søren A
authors: SA
authors: Jensen
authors: Yunan
authors: Y
authors: Gao
authors: Arjan J
authors: AJ
authors: Houtepen
authors: Laurens D A
authors: LD
authors: Siebbeles
authors: Sachin
authors: S
authors: Kinge
authors: M
authors: M
authors: Bonn