cm5b00503_si_001.pdf (938.32 kB)
Reconfigurable Nanorod Films: An in Situ Study of the Relationship between the Tunable Nanorod Orientation and the Optical Properties of Their Self-Assembled Thin Films
journal contribution
posted on 2015-04-14, 00:00 authored by Christian
R. Ocier, Detlef-M. Smilgies, Richard D. Robinson, Tobias HanrathUnderstanding
and controlling the self-assembly of colloidal nanostructures
into ordered superstructures present scientifically interesting and
technologically important research challenges. Here, we investigated
the self-assembly, disordering, and reassembly of colloidal CdSe/CdS
dot/rod nanorod (NR) films. We monitored the structural evolution
of the NR films in real time
using in situ grazing incidence small-angle and wide-angle
X-ray scattering. In dry films, self-assembled from colloidal suspensions,
NRs are oriented with the long axis normal to the substrate, but the
preferred NR orientation is lost when dichlorobenzene vapor is introduced.
Multiprobe optical and structural experiments allowed us to directly
correlate the NR superlattice structure and optical absorption. We
found that the optical absorption of the NR films is significantly
enhanced in disordered NR films compared to NR arrays in which the
rods are oriented normal to the plane of the substrate and parallel
to the optical axis. Basic processing–structure–property
relationships of NR thin films demonstrate that their structure and
optical properties can be reconfigured through the adjustment of solvent
vapor concentration. The phase behavior and optical properties of
NRs present an interesting inorganic analogue to organic liquid crystals
with potential applications in emerging optoelectronic technologies.