Reducing strain and fracture of electrophoretically deposited CdSe nanocrystal films. I. Postdeposition infusion of capping ligands.

Thick electrophoretically deposited (EPD) films of ligand-capped colloidal nanocrystals that adhere to the substrate typically crack after they are removed from the deposition solvent due to the loss of residual solvent. We report the suppression of fracture in several micrometers thick EPD films of CdSe nanocrystals by treating the wet, as-deposited films with solutions containing the NC core-capping ligand, trioctylphosphine oxide (TOPO). The increase in TOPO ligand density increases photoluminescence of the dried film and leads to a decrease in elastic modulus.

Reducing strain and fracture of electrophoretically deposited CdSe nanocrystal films. II. Postdeposition infusion of monomers.

Thick electrophoretically deposited (EPD) films of ligand-capped colloidal nanocrystals (NCs) typically crack when removed from the deposition solvent due to the loss of residual solvent. We report the suppression of fracture in several micrometers thick EPD films of CdSe NCs by treating the wet, as-deposited films with solutions of polymer precursor monomers, followed by UV-initiated polymerization. The monomers diffuse into voids and, for several monomers, dissolve the NCs to form a uniform dispersion in the film.