Seminar Title
Spontaneous modulation doping in semi-crystalline conjugated polymers
Seminar Type
Departmental Seminar
Department
Physics and Astronomy
Speaker Name
Aditya Dash
Speaker Type
External Academic
Venue
MC126
Date & Time
03 Jan 2024 11:00 AM
Contact
Prof P N Viswakarma
Abstract
The possibility to control the charge carrier density through doping is one of the defining properties
of semiconductors. For organic semiconductors, the doping process is known to come with several
problems associated with the dopant compromising the charge carrier mobility by deteriorating the
host morphology and/or introducing Coulomb traps. While for inorganic semiconductors these factors
can be mitigated through (top-down) modulation doping, this concept has not been employed in
organics. Here, we show that properly chosen host/dopant combinations can give rise to spontaneous,
bottom-up modulation doping, in which the dopants preferentially sit in an amorphous phase, while
the actual charge transport occurs predominantly in a crystalline phase with an unaltered
microstructure, spatially separating dopants and mobile charges. Combining experiments and
numerical simulations, we show that this leads to exceptionally high conductivities at relatively low
dopant concentrations.