AVS 46th International Symposium
    Organic Electronic Materials Topical Conference Monday Sessions
       Session OE+EM+FP-MoM

Paper OE+EM+FP-MoM5
Femtosecond Charge Transfer Processes in Organic Molecular Heterostructures

Monday, October 25, 1999, 9:40 am, Room 616/617

Session: Organic Devices
Presenter: A.J. Mäkinen, University of Rochester
Authors: A.J. Mäkinen, University of Rochester
S. Schoemann, University of Rochester
Y. Gao, University of Rochester
M.G. Mason, Eastman Kodak Company
A.A. Muenter, Eastman Kodak Company
A.R. Melnyk, Xerox Wilson Center for Research & Technology
Correspondent: Click to Email
The charge transfer (CT) process in organic semiconductor heterostructures is an important problem for applications such as photoreceptors and light-emitting devices. The operation of a photoreceptor structure is based on a CT process at the interface of a charge generator layer and a charge transport layer. We have investigated such a structure formed by vacuum grown thin films of two organic molecules, N,N'-diphenethyl-3,4,9,10- perylenetetracarboxylic-diimide (DPEP) and N,N'-diphenyl-N,N'-(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine (TPD), with femtosecond time-resolved photoemission spectroscopy (TR-PES). By measuring the lifetimes of the excited electron states in the mixtures and in the bilayer structures of these molecules, and by recording the UPS spectra of the films we are able to determine the time-scale and the energy regime for the CT process. Our results show that the CT takes place in less than 10 fs between the DPEP and the TPD molecules. We also demonstrate the significance of the film interface in separating the charges upon CT.