Solid-State Chemistry on the Nanoscale: Ion Transport through Interstitial Sites or Vacancies?
How can ion-exchange process occur in nanocrystals without the size and shape changing and why is the ion transport much faster than in classical interdiffusion processes in macrocrystalline solids? We have investigated these processes at the molecular level by means of high-resolution and analytical electron microscopy in temperature-dependent kinetic experiments for several model reactions. The results clearly show a diffusion process that proceeds exclusively through the interstitial lattice positions with a subsequent "kick out" to remove individual ions from lattice sites without the formation of vacancies. This mechanism has not been observed in nanocrystalline systems before.
Institut für Physikalische Chemie, Fachbereich Chemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg (Germany).
Cornelia
C
Bothe
Institut für Physikalische Chemie, Fachbereich Chemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg (Germany).
Andreas
A
Kornowski
Institut für Festkörperphysik, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin (Germany).
Hans
H
Tornatzky
Institut für Physikalische Chemie, Fachbereich Chemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg (Germany).
Christian
C
Schmidtke
Institut für Physikalische Chemie, Fachbereich Chemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg (Germany).|The Hamburg Centre for Ultrafast Imaging (CUI), Luruper Chaussee 149, 22761 Hamburg (Germany).
Holger
H
Lange
Institut für Festkörperphysik, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin (Germany).
Janina
J
Maultzsch
Institut für Physikalische Chemie, Fachbereich Chemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg (Germany). weller@chemie.uni-hamburg.de.|Centrum für Angewandte Nanotechnologie, Grindelallee 117, 20146 Hamburg (Germany). weller@chemie.uni-hamburg.de.|The Hamburg Centre for Ultrafast Imaging (CUI), Luruper Chaussee 149, 22761 Hamburg (Germany). weller@chemie.uni-hamburg.de.|Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah (Saudi Arabia). weller@chemie.uni-hamburg.de.
Horst
H
Weller
PbSe; ZnSe; cation exchange; nanoparticles; reaction kinetics