Microscopic theory of cation exchange in CdSe nanocrystals.
Although poorly understood, cation-exchange reactions are increasingly used to dope or transform colloidal semiconductor nanocrystals (quantum dots). We use density-functional theory and kinetic Monte Carlo simulations to develop a microscopic theory that explains structural, optical, and electronic changes observed experimentally in Ag-cation-exchanged CdSe nanocrystals. We find that Coulomb interactions, both between ionized impurities and with the polarized nanocrystal surface, play a key role in cation exchange. Our theory also resolves several experimental puzzles related to photoluminescence and electrical behavior in CdSe nanocrystals doped with Ag.
Optical Materials Engineering Laboratory, ETH Zurich, 8092 Zurich, Switzerland.
Florian D
FD
Ott
Optical Materials Engineering Laboratory, ETH Zurich, 8092 Zurich, Switzerland.
Leo L
LL
Spiegel
Optical Materials Engineering Laboratory, ETH Zurich, 8092 Zurich, Switzerland.
David J
DJ
Norris
Center for Computational Materials Science, Naval Research Laboratory, Washington, D.C. 20375, USA.
Steven C
SC
Erwin