BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Unified Description of Charge-Carrier Mobilities in Disordered Sem
 iconducting Polymers - Dr Peter Bobbert\, Eindhoven University of Technolo
 gy
DTSTART:20051122T141500Z
DTEND:20051122T151500Z
UID:TALK4534@talks.cam.ac.uk
CONTACT:Chris McNeill
DESCRIPTION:Traditionally\, much attention has been given to the dependenc
 e of the charge-carrier mobility in disordered semiconducting polymers on 
 the electric field.\nHowever\, it has recently become clear that the depen
 dence of the mobility on the charge-carrier density cannot be neglected\, 
 not even in polymer light-emitting diodes\, where this density is very low
 . From a numerical study of hopping transport on lattices with a Gaussian 
 on-site energy disorder we have come to a unified description of the depen
 dence of the mobility on density\, electric field\, and temperature. With 
 this description\, experimental current-voltage characteristics of hole-on
 ly devices with PPV derivatives as semiconductor can be fitted excellently
 . We come to the conclusion that the traditionally supposed electric field
  dependence of the mobility is actually\, for a large part\, a density dep
 endence. Only at high voltages and low temperatures the dependence on elec
 tric field becomes important and this dependence can also be excellently m
 odeled with our description.
LOCATION:IRC Superconductivity Seminar Room\, Cavendish Laboratory\, Depar
 tment of Physics
END:VEVENT
END:VCALENDAR