5 research outputs found
Block Copolymer with an Extremely High Block-to-Block Interaction for a Significant Reduction of Line-Edge Fluctuations in Self-Assembled Patterns
Directed
self-assembly (DSA) of block copolymers (BCPs) with a
high Flory–Huggins interaction parameter (χ) provides
advantages of pattern size reduction below 10 nm and improved pattern
quality. Despite theoretical predictions, however, the questions of
whether BCPs with a much higher χ than conventional high-χ
BCPs can further improve the line edge roughness (LER) and how to
overcome their extremely slow self-assembly kinetics remain unanswered.
Here, we report the synthesis and assembly of poly(4vinylpyridine-<i>b</i>-dimethylsiloxane) BCP with an extremely high χ-parameter
(estimated to be approximately 7 times higher compared to that of
poly(styrene-<i>b</i>-dimethylsiloxane) – a conventional
high-χ BCP) and achieve a markedly low 3σ line edge roughness
of 0.98 nm, corresponding to 6% of its line width. Moreover, we demonstrate
the successful application of an ethanol-based 60 °C warm solvent
annealing treatment to address the extremely slow assembly kinetics
of the extremely high-χ BCP, considerably reducing the self-assembly
time from several hours to a few minutes. This study suggests that
the use of BCPs with an even larger χ could be beneficial for
further improvement of self-assembled BCP pattern quality
Noninvasive and Direct Patterning of High-Resolution Full-Color Quantum Dot Arrays by Programmed Microwetting
Although the commercialization of electroluminescent
quantum-dot
(QD) displays essentially demands multicolor patterning of QDs with
sufficient scalability and uniformity, the implementation of QD patterning
in a light-emitting diode device is highly challenging, mainly due
to the innate vulnerability of QDs and charge-transport layers. Here,
we introduce a noninvasive surface-wetting approach for patterning
full-color QD arrays on a photoprogrammed hole-transport layer (HTL).
To achieve noninvasiveness of QD patterning, surface-specific modification
of HTLs was performed without degrading their performance. Moreover,
engineering the solvent evaporation kinetics allows area-selective
wetting of QD patterns with a uniform thickness profile. Finally,
multicolor QD patterning was enabled by preventing cross-contamination
between different QD colloids via partial fluoro-encapsulation of
earlier-patterned QDs. Throughout the overall QD patterning process,
the optoelectronic properties of QDs and hole-transport layers are
well preserved, and prototype electroluminescent quantum dot light-emitting
diode arrays with high current efficiency and brightness were realized
Single Nanoparticle Localization in the Perforated Lamellar Phase of Self-Assembled Block Copolymer Driven by Entropy Minimization
Although
precisely controlled microdomains of block copolymers
(BCP) provide an excellent guiding matrix for multiple nanoparticles
(NPs) to be controllably segregated into a desired polymer block,
localization and positioning of individual NPs have not been demonstrated.
Here, we report a unique one-to-one positioning phenomenon of guest
Au NPs in the host BCP microdomains; each of polystyrene-functionalized
Au NPs is embedded within the perforation domain of hexagonally perforated
lamellar (HPL) morphology of poly(dimethylsiloxane-<i>b</i>-styrene) BCP. The local minimization of free energy achieved by
the placement of Au NPs into the center of the perforation domain
is theoretically supported by the self-consistent field theory (SCFT)
simulation. We propose a novel design principle for more precisely
controllable nanocomposites by developing a new route of NP arrangement
within a polymer matrix
Topographically-Designed Triboelectric Nanogenerator via Block Copolymer Self-Assembly
Herein,
we report a facile and robust route to nanoscale tunable
triboelectric energy harvesters realized by the formation of highly
functional and controllable nanostructures via block copolymer (BCP)
self-assembly. Our strategy is based on the incorporation of various
silica nanostructures derived from the self-assembly of BCPs to enhance
the characteristics of triboelectric nanogenerators (TENGs) by modulating
the contact-surface area and the frictional force. Our simulation
data also confirm that the nanoarchitectured morphologies are effective
for triboelectric generation
Topographically-Designed Triboelectric Nanogenerator via Block Copolymer Self-Assembly
Herein,
we report a facile and robust route to nanoscale tunable
triboelectric energy harvesters realized by the formation of highly
functional and controllable nanostructures via block copolymer (BCP)
self-assembly. Our strategy is based on the incorporation of various
silica nanostructures derived from the self-assembly of BCPs to enhance
the characteristics of triboelectric nanogenerators (TENGs) by modulating
the contact-surface area and the frictional force. Our simulation
data also confirm that the nanoarchitectured morphologies are effective
for triboelectric generation