BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Hyperspectral imaging of exciton dynamics in individual carbon nan
 otubes controlled by high magnetic fields - Dr Jack J. Alexander-Webber\, 
 University of Oxford
DTSTART:20140228T110000Z
DTEND:20140228T120000Z
UID:TALK51211@talks.cam.ac.uk
CONTACT:Teri Bartlett
DESCRIPTION:Semiconducting carbon nanotubes (CNTs) provide an exceptional 
 platform for studying one dimensional excitons (bound electron-hole pairs)
 \, but the role of defects and quenching centres in controlling emission r
 emains controversial. Here we show that by wrapping the CNT in a polymer s
 heath and cooling to 4.2 K\, ultra-narrow photoluminescence (PL) emission 
 linewidths below 80 micro-eV can be seen from individual solution processe
 d CNTs. Hyperspectral imaging of the tubes identifies local emission sites
  and shows that previously dark quenching segments can be brightened by th
 e application of high magnetic fields and their effect on exciton transpor
 t and dynamics can be controlled. Using focused high intensity laser irrad
 iation we introduce a single defect into an individual nanotube which redu
 ces its quantum efficiency by the creation of a shallow bound exciton stat
 e with enhanced electron-hole exchange interaction. The emission intensity
  of the nanotube is then reactivated by the application of the high magnet
 ic field.
LOCATION:Mott Seminar Room\, Cavendish Laboratory\, Department of Physics
END:VEVENT
END:VCALENDAR