BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Studying polaron generation and recombination in pristine films of
  conjugated polymer P3HT - Steffan Cook\, National Institute of Advanced I
 ndustrial Science and Technology
DTSTART:20110208T143000Z
DTEND:20110208T153000Z
UID:TALK29589@talks.cam.ac.uk
CONTACT:Jenny Clark
DESCRIPTION:It is becoming increasingly apparent that films of regioregula
 r poly(3-hexylthiophene) [RR- P3HT] are one of those rare cases in organic
  semiconductors where absorption of photons leads to high yields of 'insta
 ntaneously' photo-generated charges. Of course neutral singlet excited sta
 tes are also formed\, but with the neutral singlet state absorption peak a
 t 1200 nm\, greatly red-shifted against the polaron peak at 800 nm\, this 
 offers an ideal opportunity for femtosecond optical pump-probe measurement
 s to study the behaviour of polarons in P3HT without worrying about interf
 erence from the singlet state. Here we will look at the kinetics of charge
  (polaron) generation and recombination in films of RR-P3HT as a function 
 of\; laser power\, excitation wavelength and pulse repetition rate\, and w
 e will calculate the efficiency of polaron formation per absorbed photon i
 n P3HT. We describe a model to explain the laser power dependence of the P
 3HT polaron recombination kinetics (which gives us some insight into charg
 e recombination in organic solar cells and light emitting diodes)\, and ha
 ve a crack at explaining the mechanism of charge generation itself and why
  it's so high in P3HT. This work is as yet unpublished and this will be th
 e first talk given on the new photophysics outside Japan.
LOCATION:Kapitza Building Seminar Room\, Cavendish Laboratory\, Department
  of Physics
END:VEVENT
END:VCALENDAR