
Proceedings Paper
Ultrafast exciton dissociation at donor/acceptor interfacesFormat | Member Price | Non-Member Price |
---|---|---|
$17.00 | $21.00 |
Paper Abstract
Charge generation at donor/acceptor interface is a highly debated topic in the organic photovoltaics (OPV)
community. The primary photoexcited state evolution happens in few femtosecond timescale, thus making very
intriguing their full understanding. In particular charge generation is believed to occur in < 200 fs, but no clear picture
emerged so far. In this work we reveal for the first time the actual charge generation mechanism following in real time
the exciton dissociation mechanism by means of sub-22 fs pump-probe spectroscopy. We study a low-band-gap polymer:
fullerene interface as an ideal system for OPV. We demonstrate that excitons dissociation leads, on a timescale of 20-50
fs, to two byproducts: bound interfacial charge transfer states (CTS) and free charges. The branching ratio of their
formation depends on the excess photon energy provided. When high energy singlet polymer states are excited, well
above the optical band gap, an ultrafast hot electron transfer happens between the polymer singlet state and the
interfacial hot CTS* due to the high electronic coupling between them. Hot exciton dissociation prevails then on internal
energy dissipation that occurs within few hundreds of fs. By measuring the internal quantum efficiency of a prototypical
device a rising trend with energy is observed, thus indicating that hot exciton dissociation effectively leads to a higher
fraction of free charges.
Paper Details
Date Published: 11 September 2013
PDF: 8 pages
Proc. SPIE 8811, Physical Chemistry of Interfaces and Nanomaterials XII, 88111D (11 September 2013); doi: 10.1117/12.2021133
Published in SPIE Proceedings Vol. 8811:
Physical Chemistry of Interfaces and Nanomaterials XII
Natalie Banerji; Carlos Silva, Editor(s)
PDF: 8 pages
Proc. SPIE 8811, Physical Chemistry of Interfaces and Nanomaterials XII, 88111D (11 September 2013); doi: 10.1117/12.2021133
Show Author Affiliations
G. Grancini, Istituto Italiano di Tecnologia (Italy)
D. Fazzi, Istituto Italiano di Tecnologia (Italy)
M. Binda, Istituto Italiano di Tecnologia (Italy)
M. Maiuri, Politecnico di Milano (Italy)
A. Petrozza, Istituto Italiano di Tecnologia (Italy)
L. Criante, Istituto Italiano di Tecnologia (Italy)
D. Fazzi, Istituto Italiano di Tecnologia (Italy)
M. Binda, Istituto Italiano di Tecnologia (Italy)
M. Maiuri, Politecnico di Milano (Italy)
A. Petrozza, Istituto Italiano di Tecnologia (Italy)
L. Criante, Istituto Italiano di Tecnologia (Italy)
S. Perissinotto, Istituto Italiano di Tecnologia (Italy)
H.-J. Egelhaaf, BELECTRIC OPV GmbH (Germany)
D. Brida, Politecnico di Milano (Italy)
G. Cerullo, Politecnico di Milano (Italy)
G. Lanzani, Istituto Italiano di Tecnologia (Italy)
H.-J. Egelhaaf, BELECTRIC OPV GmbH (Germany)
D. Brida, Politecnico di Milano (Italy)
G. Cerullo, Politecnico di Milano (Italy)
G. Lanzani, Istituto Italiano di Tecnologia (Italy)
Published in SPIE Proceedings Vol. 8811:
Physical Chemistry of Interfaces and Nanomaterials XII
Natalie Banerji; Carlos Silva, Editor(s)
© SPIE. Terms of Use
