Energy transfer and selective hole injection in blended conjugated polymer nanoparticles

PHYS 471

Ya-Lan Chang, ylchang@mail.utexas.edu, Wei-Shun Chang, wschang@mail.utexas.edu, Fu-Ren F. Fan, Rodrigo E. Palacios, rodpalacios@mail.utexas.edu, Allen J. Bard, ajbard@mail.utexas.edu, and Paul F. Barbara, p.barbara@mail.utexas.edu. Department of Chemistry and Biochemistry, University of Texas at Austin, Center for Nano- and Molecular Science and Technology, Mail Code A5500, Austin, TX 78712
Energy transfer and selective hole injection in polymer nanoparticles composed of F8BT (donor) doped with single polymer chain BEH-PPV (acceptor) was studied with the new electrochemical single molecule spectroscopy (EC-SMS) technique. In particles containing 1% BEH-PPV, the acceptor component showed fluorescence intermittency suggesting that single chain doping levels were achieved at this concentration. Assuming an average nanoparticle diameter of 25nm, we estimated a Förster radius of 5.4nm via the fraction of acceptor fluorescence of 13% for 1% blend nanoparticle. Selective hole injection to the acceptor was observed where holes are localized on BEH-PPV chains. A symmetric and reversible fluorescence-intensity modulation of the 1% blend nanoparticles with an applied pulse bias of 0.9V suggests that the injected holes do not become deeply trapped. This result suggests multi-chain of the same polymer is required to cause the relaxation of chemical structure, which is a possible source of deep traps.
 

PHYS Poster Session - Nanostructured Materials and Nanophotonics
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster

Division of Physical Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008