Format

Send to

Choose Destination
See comment in PubMed Commons below
Science. 2012 Mar 16;335(6074):1340-4. doi: 10.1126/science.1217745. Epub 2012 Feb 23.

The role of driving energy and delocalized States for charge separation in organic semiconductors.

Author information

1
Cavendish laboratory, University of Cambridge, Cambridge, UK.

Abstract

The electron-hole pair created via photon absorption in organic photoconversion systems must overcome the Coulomb attraction to achieve long-range charge separation. We show that this process is facilitated through the formation of excited, delocalized band states. In our experiments on organic photovoltaic cells, these states were accessed for a short time (<1 picosecond) via infrared (IR) optical excitation of electron-hole pairs bound at the heterojunction. Atomistic modeling showed that the IR photons promote bound charge pairs to delocalized band states, similar to those formed just after singlet exciton dissociation, which indicates that such states act as the gateway for charge separation. Our results suggest that charge separation in efficient organic photoconversion systems occurs through hot-state charge delocalization rather than energy-gradient-driven intermolecular hopping.

PMID:
22362882
DOI:
10.1126/science.1217745
Free full text
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire
    Loading ...
    Support Center