Assembly of CdSe nanocrystals into well-ordered monolayers with a strong crystallographic texture

Nanocrystals of CdSe stabilized with tri-w-octyl phosphine oxide molecules have been synthesized by a colloidal route and fractionated to give a sharp monomodal size distribution. Self-assembled monolayers of nanocrystals with 6.2 nm CdSe cores have been produced by controlled evaporation from solution on to an amorphous carbon substrate. The monolayers have been studied using transmission electron microscopy and it has been found that they exhibit both a well-defined long-range order and a strong crystallographic texture. It is shown that these effects are related to the faceted tabular morphology adopted by the nanocrystal cores.