Efficient exciton separation in mixed films of CdSe and CdTe nanoparticles

INOR 29

Venda J Porter, vporter@mit.edu1, Jonathan E Halpert, jhalpert@mit.edu1, Gautham P Nair, gautham@mit.edu1, Tamar Mentzel2, Marc A. Kastner2, and Moungi G. Bawendi, mgb@mit.edu1. (1) Department of Chemistry, Massachusetts Institute of Technology, 18-080, 77 Massachusetss Ave, Cambridge, MA 02139, (2) Department of Physics, MIT, 77 Massachusetss Ave, Cambridge, MA 02139
There is currently much interest in using semiconducting nanoparticles in photovolatics because they can be tuned to absorb a range of wavelengths. Converting light absorbed by a nanoparticle into current requires application of an external voltage to separate the exciton into charge carriers and transport them to electrodes. CdTe/CdSe core/shell heterostructures display type-II behavior as the band offsets of the two semiconductors cause the electron to reside in the CdSe shell and the hole in the CdTe core. CdSe and CdTe QDs are mixed in a close-packed film to use the type-II effect to reduce the external voltage needed to separate excitons into mobile charge carriers. The voltage required for exciton separation is lowered further through chemical treatments which decrease interparticle spacing. Other nanoparticle heterostructures, such as CdSe rods with CdTe QDs at each end, are also explored in order to better extract charges after exciton separation.
 

Application of Inorganic Chemistry in Nanoscience
9:00 AM-12:00 PM, Sunday, 26 March 2006 Georgia World Congress Center -- B403, Oral

Division of Inorganic Chemistry

The 231st ACS National Meeting, Atlanta, GA, March 26-30, 2006