Self-assembled multilayers of nanocomponents.

graphical abstract
Krishnan, R.S.; Mackay, M.E.; Duxbury, P.M.; Pastor, A.; Hawker, C.J.; Van Horn, B.; Asokan, S.; Wong, M.S.;
Nanoletters,
2007
7, 484-489.

We show it is possible to assemble nanoparticle−polymer layers in a controllable manner dictated by the difference in nano-object morphology and dielectric properties. A thin (10−100 nm) layer of the two components is spin coated onto a solid substrate and the system thermally aged to activate a cross-linking process between polymer molecules. The nanoparticles segregate to the solid substrate prior to complete cross-linking if entropic forces are dominant or to the air interface if dielectric (surface energy) forces are properly tuned. Subsequent layers are then spin coated onto the layer below, and the process is repeated to create layered structures with nanometer accuracy useful for tandem solar cells, sensors, optical coatings, etc. Unlike other self-assembly techniques the layer thicknesses are dictated by the spin coating conditions and relative concentration of the two components.