We propose a technique for one-step micropatterning of as-grown carbon-nanotube films on a plastic substrate with sub-10 μm resolution on the basis of the dry transfer process. By utilizing this technique, we demonstrated the novel high-performance flexible carbon-nanotube transparent conductive film with a microgrid structure, which enabled improvement of the performance over the trade-off between the sheet resistance and transmittance of a conventional uniform carbon-nanotube film. The sheet resistance was reduced by 46% at its maximum by adding the microgrid, leading to a value of 53 Ω/sq at a transmittance of 80%. We also demonstrated easy fabrication of multitouch projected capacitive sensors with 12 × 12 electrodes. The technique is quite promising for energy-saving production of transparent conductor devices with 100% material utilization.
We report a continuous floating catalyst chemical vapor deposition synthesis of highly individual single-walled carbon nanotubes (SWCNT) for high performance transparent conducting films (TCF). Active feedback dilution of ferrocene-based catalyst vapor leads to an almost complete elimination of SWCNT bundling and a substantial increase in SWCNT lengths via the suppression of bundling-induced growth termination. The fabricated uniform TCFs exhibit sheet resistances of 89 Ω/sq. at 90% transmittance. This was further improved by micro-patterning, resulting in a sheet resistance of 69 Ω/sq. at 97% transmittance-the highest reported for any carbon nanotube TCFand highly competitive with commercial indium-tin-oxide-TCFs. Furthermore, we demonstrate that thin film transistors fabricated from these highly individual SWCNTs reach charge carrier mobilities up to 100 cm 2 V-1 s-1 and ON/OFF-ratios up to 10 6 .
We
report the thermodynamic and kinetic aqueous self-assembly of
a series of amide-functionalized dithienyldiketopyrrolopyrroles (TDPPs)
that bear various hydrophilic oligoethylene glycol (OEG) and hydrophobic
alkyl chains. Spectroscopic and microscopic studies showed that the
TDPP-based amphiphiles with an octyl group form sheet-like aggregates
with J-type exciton coupling. The effect of the alkyl chains on the
aggregated structure and the internal molecular orientation was examined
via computational studies combining MD simulations and TD-DFT calculations.
Furthermore, solvent and thermal denaturation experiments provided
a state diagram that indicates the formation of unexpected nanoparticles
during the self-assembly into nanosheets when longer OEG side chains
are introduced. A kinetic analysis revealed that the nanoparticles
were obtained selectively as an on-pathway intermediate state toward
the formation of thermodynamically controlled nanosheets. The metastable
aggregates were used for seed-initiated supramolecular assembly, which
allowed establishing control over the assembly kinetics and the aggregate
size. The sheet-like aggregates prepared using the seeding method
exhibited coherent vibration in the excited state, indicating a well-ordered
orientation of the TDPP units. These results underline the significance
of fine tuning of the hydrophobic/hydrophilic balance in the molecular
design to kinetically control the assembly of amphiphilic π-conjugated
molecules into two-dimensional nanostructures in aqueous media.
The self‐assembly of an amide‐functionalized dithienyldiketopyrrolopyrrole (DPP) dye in aqueous media was achieved through seed‐initiated supramolecular polymerization. Temperature‐ and time‐dependent studies showed that the spontaneous polymerization of the DPP derivative was temporally delayed upon cooling the monomer solution in a methanol/water mixture. Theoretical calculations revealed that an amide‐functionalized DPP derivative adopts an energetically favorable folded conformation in the presence of water molecules due to hydration. This conformational change is most likely responsible for the trapping of monomers in the initial stage of the cooperative supramolecular polymerization in aqueous media. However, the monomeric species can selectively interact with externally added fragmented aggregates as seeds through concerted π‐stacking and hydrogen‐bonding interactions. Consequently, the time course of the supramolecular polymerization and the morphology of the aggregated state can be controlled, and one‐dimensional fibers that exhibit a J‐aggregate‐like bathochromically shifted absorption band can be obtained.
Hydrophobicity-driven folding of cystine-based dimeric diamides with aromatic substituents at the C- and N-termini slows their spontaneous assembly and thus seeded supramolecular polymerization was achieved in aqueous media.
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