revealed by TEM (e.g., 90–170 nm for V(1), 90–130 nm for
Y(3), and 40–60 nm for X(2) assemblies (ESI Fig. S1w), which
were in agreement with the optical data. Both aryl ethynyl
shape- and size-determined interparticle structural effects are
believed to be operative in the assembly process, the detailed
understanding of which requires a more systematic tuning of
the structures. A certain degree of intershell overlap is also
believed to operate for the growth of larger-sized assemblies at
a slower assembly rate. This type of interparticle structural
control of optical and spectroscopic properties have important
implications to enabling the design of a wide range of
nanoparticle assembly systems for potential applications in
chemical/biosensing, spectroscopic signal amplification, and
microelectronics.
Fig. 4 Raman spectra for two sets of samples: (A) V-(a), Y-(b), and
V–Y-(c) mediated assemblies; (B) V-(a), X-(d), and V–X-(e) mediated
assemblies.
This work was supported by the National Science Foundation
(CHE 0848701) USA, and by the National Natural Science
Foundation of China (No. 20672033) and Hunan Provincial
Natural Science Foundation of China (No. 07JJ3026). HY
acknowledges the support of a fellowship from China Scholarship
Council.
Scheme 2 A schematic illustration of the nanoparticle assembly by
two mediators (e.g., V(1) and Y(3)) in a sequential addition process,
involving a partial disassembly of V-NPs and an assembly of the
partially-disassembled V-NPs and NPs toward (V + Y)-NPs.
Notes and references
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ꢁc
This journal is The Royal Society of Chemistry 2010
2220 | Chem. Commun., 2010, 46, 2218–2220