Photosynthetic organisms organize discrete light-harvesting complexes into large-scale networks to facilitate efficient light collection and utilization. Inspired by nature, herein, synthetic DNA templates were used to direct the formation of dye aggregates with a cyanine dye, K21, into discrete branched photonic complexes, and two-dimensional (2D) excitonic networks. The DNA templates ranged from four-arm DNA tiles, � 10 nm in each arm, to 2D wireframe DNA origami nanostructures with different geometries and varying dimensions up to 100 × 100 nm. These DNAtemplated dye aggregates presented strongly coupled spectral features and delocalized exciton characteristics, enabling efficient photon collection and energy transfer. Compared to the discrete branched photonic systems templated on individual DNA tiles, the interconnected excitonic networks showed approximately a 2-fold increase in energy transfer efficiency. This bottom-up assembly strategy paves the way to create 2D excitonic systems with complex geometries and engineered energy pathways.
Onion-like carbons (OLCs) are a class
of fullerene-like circular
nanoallotropes of carbon, typically synthesized from nanodiamond (ND) via thermal annealing, plasma spraying, and laser ablation.
These methods require high temperature, high vacuum, or inert gas.
Here, we report an ambient electrospray deposition (AESD) process
to transform NDs (11 ± 1 nm in size) into OLCs (50 ± 13
nm in size) in water. Transmission electron microscopy (TEM), field
emission scanning electron microscopy (FESEM), Raman spectroscopy,
and X-ray photoelectron spectroscopy (XPS) were used for the characterization
of NDs and OLCs. High-resolution TEM images showed an increased interplanar
spacing from ND (0.23 nm) to OLC (0.39 nm). Raman spectra showed a
shift in the ND peak from 1336 cm–1 to D-band at
1349 cm–1, and XPS quantitatively estimated an increase
in the graphitization ratio (sp2/sp3) from 0.95
to 3.16 after AESD. Comparison of electrospray with sonic spray confirmed
that such a transformation required an external voltage as well. AESD
was also performed for NDs dispersed in ethanol and acetonitrile,
which showed a solvent-dependent transformation.
Photosynthetic organisms organize discrete light-harvesting complexes into large-scale networks to facilitate efficient light collection and utilization. Inspired by nature, herein, synthetic DNA templates were used to direct the formation of dye aggregates with a cyanine dye, K21, into discrete branched photonic complexes, and two-dimensional (2D) excitonic networks. The DNA templates ranged from four-arm DNA tiles, � 10 nm in each arm, to 2D wireframe DNA origami nanostructures with different geometries and varying dimensions up to 100 × 100 nm. These DNAtemplated dye aggregates presented strongly coupled spectral features and delocalized exciton characteristics, enabling efficient photon collection and energy transfer. Compared to the discrete branched photonic systems templated on individual DNA tiles, the interconnected excitonic networks showed approximately a 2-fold increase in energy transfer efficiency. This bottom-up assembly strategy paves the way to create 2D excitonic systems with complex geometries and engineered energy pathways.
Nanomaterials are nanostructures that have gained massive interest in the scientific community due to their exciting functional and physicochemical properties. They offer high stability, advanced optical-electronic properties, and tuneable surface functionalization. Such properties have made them a material of everyday use in the pharmaceutical industries, cosmetics, electronics, and many more. Considering their increasing usage, there is a demand for reliable and better quantitative and qualitative characterization tools. This chapter is dedicated to such characterization methodologies for the analysis of nanomaterials. Numerous distinct and integrated correlated techniques are discussed in detail. Such tools are arranged from the basic to advanced methods, each mentioning the unique property of nanomaterial such as elemental composition, morphology, crystal structure, magnetism, and strength. Lastly, some recent advancements in the characterization methodologies of nanostructures are provided. Understanding the properties of nanomaterials will enable us to expand their applications in society.
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