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 used 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. 
Florian D. Ott, Leo L. Spiegel, David J. Norris, Steven C. Erwin
cond-mat.mes-hall cond-mat.mtrl-sci