Photoinduced Electron Transfer at Interfaces between Molecules and Semiconductor Nanoparticles

Piotr Piotrowiak,
Rutgers University - Newark

Host-guest complexes (hemicarceplexes) consisting of chromophores imprisoned within hemicarcerand “molecular containers” were used to study the propagation of the donor-acceptor electronic coupling across the intervening wall of the molecular cage.  Using these systems it was possible to demonstrate the existence of the Marcus “inverted region” in triplet energy transfer and to analyze the strong dependence of electronic energy transfer processes on the internal reorganization energy of the donor and the acceptor.   In a separate study the dependence of the energy transfer rate, and hence the magnitude of the donor-acceptor electronic interaction, on the size of the molecular cage was investigated.

The second part of the seminar will be devoted to charge injection processes at molecule-semiconductor interfaces.  Size-selective sensors composed of host-guest assemblies (hemicarceplexes) covalently bound to nanoparticles of a wide-band semiconductor will be described.  Water soluble hemicarcerands are used to efficiently trap appropriately sized hydrophobic chromophores whose presence within the molecular container is subsequently detected by photoinduced electron injection from the chromophore into the conduction band of the semiconductor.  Lastly, we will report the progress of a collaborative project on ultrafast interfacial charge injection from “molecular tripods“ (designed and synthesized by the group of E. Galoppini) into mesoporous TiO2 films.

 Abstract in MS Word format.

Date:  
Thursday, September 18, 2003
12:00 noon, room 260, Wright-Rieman Chemistry Laboratory
Lunch:  11:45 a.m.