Ultrafast Electron Transfer from Photoexcited CdSe Quantum Dots to Methylviologen

作者：Scholz Frank; Dworak Lars; Matylitsky Victor V; Wachtveitl Josef^*

来源：ChemPhysChem, 2011, 12(12): 2255-2259.

DOI：10.1002/cphc.201100120

• charge separation
• dyes/pigments
• electron transfer
• Marcus theory
• quantum dots

The ultrafast charge separation at the quantum dot (QD)/molecular acceptor interface was investigated in terms of acceptor concentration and the size of the QD. Time-resolved experiments revealed that the electron transfer (ET) from the photo-excited QD to the molecular acceptor methylviologen (MV(2+)) occurs on the fs time scale for large acceptor concentrations and that the ET rate is strongly reduced for low concentrations. The increase in the acceptor concentration is accompanied with a growth in the overlap of donor and acceptor wavefunctions, resulting in a faster reaction until the MV(2+) concentration reaches a saturation limit of 0.3-0.4 MV(2+) nm(-2). Moreover, we found significant QD size dependence of the ET reaction, which is explained by a change of the free energy (Delta G).

• 出版日期2011-8-22