Biology Reference
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In addition, the availability of these high-quality nanocrystals
has provided an opportunity to systematically study nanocrystal
assembly.
The ability to assemble nanocrystals (or artificial
atoms) into desired and higher ordered architectures will allow
the rational control of the electronic, plasmonic, and/or magnetic
coupling between artificial atoms, enabling nanocrystal assemblies
to have unique and collective physical properties.
11
13
14,15
This ability also
allows for the creation of multifunctional materials by combining
two or more independently tailored nanocrystal building blocks.
15
Assembling nanocrystals can open a new avenue to designing and
fabricating functional materials of interest for application in areas
such as biomedical diagnosis, catalysis, plasmonics, high-density
data storage, and energy conversion.
To date, many methods have
been developed for the preparation of nanocrystal thin films and
colloidal crystals with a variety of nanocrystals having different
size, shape, and compositions.
6
6,12,13,16
These nanocrystal assemblies
exhibit either a short-range or long-range ordered structure.
15
The
long-range ordered assemblies are nanocrystal superlattices, which
can exhibit different crystal structures such as face-centered cubic,
body-centered cubic, simple hexagonal structures, or complicated
binary crystal structures.
6,11
14,16
19
The availability of nanocrystal
assemblies has led to the discovery of new collective properties of
nanocrystals. For example, magnetic binary nanocrystal superlattice
membranes exhibit collective dipolar interactions.
17
Colloidal superparticles are size- and shape-controlled
nanocrystal assemblies, and they are collections of artificial atoms in
the form of colloidal particles.
1,20
The sizes of colloidal superparticles
range from tens of nanometers to a few microns, but they exhibit
the intrinsic physical characteristics of their nanometer-sized
building blocks as well as the collective properties of these building
blocks due to coupling effects. The properties of superparticles
are tunable by varying the size, shape, and composition of their
building blocks, and/or “doping” with organic components.
20,21
Owing to their colloidal form, these superparticles are a new class
of building blocks in nanofabrication, which can be utilized to cost
effectively construct nanocrystal-based devices through solution
processing.
22
This promise has stimulated research efforts to study
superparticle formation, and a number of important methods have
been developed for making superparticles in the past decade.
1,23
25
The resulting superparticles exhibit either a short-range ordered
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