Colloidal CdSe quantum dots were chemisorbed on a gold electrode using a variety of self-assembled monolayers (SAMs) consisting of dithiols and rigid disulfides. After absorption of a photon with an energy larger than the band gap, a long-lived excited state is formed in the quantum dot; this state can decay by electron tunneling via the gold. The rate of photoinduced tunneling was measured directly by intensitymodulated photocurrent spectroscopy (IMPS), and its distance dependence was studied using rigid SAMs separating the Q-CdSe and Au. The tunneling rate was found to depend exponentially on the distance, with a decay length of 2 Å.
|Journal||Journal of Physical Chemistry B|
|Publication status||Published - 2000|