cm402465w_si_001.pdf (1.53 MB)
Layered Phosphonates in Colloidal Synthesis of Anisotropic ZnO Nanocrystals
journal contribution
posted on 2013-11-12, 00:00 authored by Bryan
M. Tienes, Russell J. Perkins, Richard K. Shoemaker, Gordana DukovicWe
describe the role of phosphonic acids in the synthesis of anisotropic
colloidal ZnO nanocrystals (nanorods) and, specifically, the discovery
of an insoluble layered Zn–phosphonate intermediate. This compound
is formed by the reaction of the molecular Zn precursor Zn(OAc)2 with phosphonic acids, and it acts as a heterogeneous Zn
source during nanocrystal formation. Layered metal phosphonates have
been studied extensively but have not been described in the context
of nanocrystal synthesis. Layered Zn–octadecylphosphonate can
be used as a sole precursor to obtain isotropic, soluble ZnO nanocrystals.
However, for anisotropic rod-like shapes both the heterogeneous and
the homogeneous (Zn(OAc)2) sources of Zn are necessary.
The existence of a heterogeneous metal source described here is in
contrast to the mechanisms of particle nucleation and growth from
homogeneous molecular precursors often used to describe nanocrystal
formation. Since many metals form layered phosphonates, our findings
have implications for synthesis of nanocrystals of other semiconductors.