"The Intriguing Challenge of Organic
and Related Nanostructures"
University College London
Department of Mathematics "L. Tonelli"
Via F. Buonarroti, 2
Aula Magna Faedo - at 15:30
The most interesting physical properties of organic semiconductors,
and of conjugated polymers in particular, are determined by the formation
of a partially delocalised π-electron system that can support
neutral and charged excitations. Such materials therefore display important
analogies to inorganic semiconductors. However, they are more disordered
than the latter. They also feature “softer lattices” and stronger electron-phonon
coupling, which together with significant electron-electron correlation effects
contribute to sizeable exciton binding energies (greater than 0.2 eV). In
spite of their reactivity and environmental instability, conjugated functional
materials have been developed intensely from a technological perspective,
up to the point that they can now be regarded as a class of semiconductors
in their own right. In fact, they enable a whole variety of applications spanning
from light-emitting (LEDs) and photovoltaic diodes, to field-effect transistors.
Some of these applications, such as LEDs and displays, have already reached
After a brief introduction to the properties of conjugated
polymers, illustrated with some notable examples, I will discuss a “top-down”
and a “bottom-up” approach to polymer nanostructures that are significant
for further probing the underlying physics and for optimisation of these
intriguing semiconductors and related devices.