Fracture in electrophoretically deposited CdSe nanocrystal films
Overview
Identity
Additional Document Info
Other
View All
Overview
abstract
We have studied the fracture, strain, and stress of electrophoretically deposited (EPD) films of CdSe nanocrystals as a function of the film thickness, nanocrystal size, and drying method. Fracture results from the film stress that develops with the loss of residual solvent after EPD when the film exceeds a threshold thickness that increases with nanocrystal core diameter from 300 to 1200 nm for core diameters from 2.3 to 5.0 nm, respectively. A hierarchical pattern of wider first generation and then narrower higher-generation cracks is observed after drying and this generational crack formation and a preferred direction for film drying are observed in real time. Delamination is seen to initiate from wider cracks, mostly between the bulk of the film and a very thin layer of nanocrystals strongly bound to the Au-coated silicon substrate. Estimates of the film toughness are made for channel cracking and delamination. 2009 American Institute of Physics.
