Weak and Strong Localization Magneto-Conductance Effects in self-doped Organic Conductor PEDOT:PSS

TYPESolid State Institute Seminar
Speaker:Mr. Daniel Nikiforov
Affiliation:Department of Physics and the Solid State Institute Technion
Time:12:30 - 13:30
Location:Solid State Auditorium(Entrance)
Remark:Ph.D. student of Professor Emeritus Eitan Ehrenfreund

Organic semiconductors are π-conjugated polymers and small molecules. One of the most studied organic conductors is poly(3
4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)
. It is a heavily doped p-type organic semiconductor.
An interesting feature of PEDOT:PSS is that its conductivity can be increased by up to three orders of magnitude by simple
addition of a polar co-solvent. This conductivity enhancement occurs as a result of structural changes in PEDOT:PSS films,
particularly by the formation of PEDOT nanocrystalline regions.
We investigated magneto-conductance (MC) in
PEDOT:PSS thin films in wide temperature (1.8-300 K) and magnetic
field (up to 14 T) ranges. We propose that
the MC response of the system combines both the weak localization effect that
takes place within the nanocrystalline PEDOT regions and the strong localization MC effect that manifests the effect of
magnetic field on the electron hopping between the high-conductivity regions. Especially, at the lowest temperatures applied
in the experiment, MC is dominated by the spin polarization effect that reduces the hopping probability between singly
occupied sites with intra-site Coulomb correlation