| 초록 |
Colloidal assemblies of semiconductor nanocrystals (NCs) are promising active materials for electronics/optoelectronic devices. These materials are typically processed into thin films based on solution processes. Chance of swelling of these assemblies during the processing can dramatically affect the morphology of the film. Here, we report experimental study on mechanical instability of crosslinked nanocrystal assemblies swollen by various solvents. When a crosslinked NC film is attached to a rigid substrate, swelling induced compressive strain causes wrinkling of the film and eventually delaminated buckling from the substrate. We present many cases of instability patterns by controlling three experimental parameters: mismatch strain, modulus, and adhesion energy between a film and a substrate. The mismatch strain, modulus, and adhesion energy are experimentally controlled by the solvent-colloids interaction parameter, the degree of crosslinking, and the type of the substrate, respectively. We demonstrate how these material properties determine surface instabilities of a crosslinked NC film. |
