Viscoplastic and granular behavior in films of colloidal nanocrystals

Phys Rev Lett. 2007 Jan 12;98(2):026103. doi: 10.1103/PhysRevLett.98.026103. Epub 2007 Jan 9.

Abstract

Nanoindentation measurements of electrophoretically deposited films of colloidal CdSe nanocrystals, capped by organic ligands, show the films have an elastic stiffness modulus of approximately 10 GPa and exhibit viscoplasticity. This mechanical response suggests polymeric features that are attributable to the ligands. After particle cross-linking and partial ligand removal, the films exhibit more features of granularity.