Direct observation of liquid crystal phases under nanoconfinement: A grazing incidence X-ray diffraction study

Ryu, Seong Ho; Ahn, Hyungju; Shin, Tae Joo; Yoon, Dong Ki

doi:10.1080/02678292.2016.1234074

Cited by 11 publications

(11 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If it is not well controlled, the molecular disorder may occur with the formation of unexpected grain boundaries, phase segregation, and other side effects, which in turn deteriorates device performance and reliability. On the other hand, a careful control of solvent evaporation can also induce specific molecular orientation due to the competition between the fluid dynamic effect and elasticity effect. − Hence, controlled solvent evaporation during the solution process of OSCs has been studied intensively. − Intra- or intermolecular charge transport of OSCs exhibits anisotropic behavior, which results from specific directional arrangement of linear π-conjugated OSCs. , …”

mentioning

confidence: 99%

Orientation Control of Semiconducting Polymers Using Microchannel Molds

Han

Kim

et al. 2020

ACS Nano

Self Cite

View full text Add to dashboard Cite

The molecular orientation of organic semiconductors (OSCs) is of fundamental importance to anisotropic electrical behavior as well as superior properties in practical applications. Here, a simple and effective method is demonstrated to fabricate highly oriented semiconducting polymers, poly(3-hexylthiophene) (P3HT) and poly{[N,N′-bis(2-octyldodecyl)-1,4,5,8-naphthalenediimide-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (P(NDI2OD-T2)), by mass transfer effect under microchannel molds by diffusion and convection. Furthermore, parallel or perpendicular molecular arrangements relative to the channel direction were achieved by varying the widths of the microchannels, which are directly observed using polarized optical microscopy and two-dimensional grazing-incidence X-ray diffraction experiments. The method could enable the fabrication of organic field-effect transistors that exhibit anisotropic electrical properties indicating inter- or intrachain charge transport. The resulting platform will provide a simple approach for multidirectional orientations of anisotropic OSCs.

show abstract

mentioning

confidence: 99%

Orientation Control of Semiconducting Polymers Using Microchannel Molds

Han

Kim

et al. 2020

ACS Nano

Self Cite

View full text Add to dashboard Cite

show abstract

“…36,37 Either a planar or perpendicular orientation can be obtained by self-assembled monolayer treatment, enabling control of the refractive index of the LC-filled nanopores (n eff,LC ). 37 Here, Au was coated on the porous AAO film, and during this process the inner surface of the AAO film was also coated to induce homeotropic anchoring of LC molecules. To confirm this orientation behavior, a sandwich cell was made using two glass slides; one slide was coated completely with Au and the other was partially coated (Figure S4).…”

Section: Resultsmentioning

confidence: 99%

“…It is well-known that rod-like LC molecules in the N phase are aligned parallel to the long axis of the AAO nanochannels because of the strong surface anchoring given by the large surface to volume ratio, known as the nanoconfinement effect. , Either a planar or perpendicular orientation can be obtained by self-assembled monolayer treatment, enabling control of the refractive index of the LC-filled nanopores ( n eff,LC ) . Here, Au was coated on the porous AAO film, and during this process the inner surface of the AAO film was also coated to induce homeotropic anchoring of LC molecules.…”

Section: Resultsmentioning

confidence: 99%

Switchable Plasmonic Film Using Nanoconfined Liquid Crystals

Ryu

Yoon

2017

ACS Appl. Mater. Interfaces

Self Cite

View full text Add to dashboard Cite

Structural coloration using plasmonic particles has received substantial attention due to its robust, permanent, and scalable characteristics across the full color range. In this study, a plasmonic structure based on a porous anodic aluminum oxide (AAO) film coated with a metallic film was fabricated. Colors were varied by changing the refractive index, which was achieved with a convolution with nanopores of AAO film and an infiltrated liquid crystal (LC) material. LC molecules confined in the porous AAO film were uniformly aligned, and they exhibited pore-size-dependent colors because of the specific refractive index. The thermal phase transition of the LC material in the nanopores changed the effective refractive index, switching the reflected colors, and the LC-infiltrated AAO remained stable over a month. We believe LC materials can extend the use of rigid conventional plasmonic structures from simple sensor applications to multifunctional uses such as color printing, writing pens, and displays.

show abstract

“…Nuclei oriented such that ψ > ψ crit , on the other hand, will re-dissolve into the solution phase. Preferential orientation of molecular crystals in the uniaxially aligned cylindrical pores of AAO has been previously reported for poly(ethylene oxide) (PEO), porous polystyrene-poly(dimethyl acrylamide) monoliths (p-PS-PDMA), poly(vinylidene fluoride) (PVDF), , and tridecafluoro-1,1,2,2-tetrahydrooctyltrichlorosilane (FOTS), among others, via 2D X-ray diffraction.…”

Section: Nanoconfined Crystallizationmentioning

confidence: 89%

Nanoconfining Optoelectronic Materials for Enhanced Performance and Stability

2019

View full text Add to dashboard Cite

The solution processing of optoelectronic active layers promises to usher in a new era of technologies, from rollable displays to smart textiles, but critical challenges remain in the processing of these materials. While solutionbased deposition of these compounds, including organic small-molecules and polymers and metal−halide perovskites, is key to driving down manufacturing costs, the rapid, uncontrolled nature of solution processing invariably results in the formation of kinetically trapped films, with heterogeneities and defects spanning multiple length scales that degrade device performance. Given such finite time, usually on the order of seconds, for molecules to organize as solvent evaporates from the active layers, the use of nanoporous scaffolds to select for desired crystallization outcomes is a promising approach to addressing this critical issue. As the size of crystals decreases, their surface free energy plays an increasingly important role in dictating their morphology and structure. By confining crystallization within the sub-micrometer pores of scaffolds, such surface free energy effects can be exploited to select for specific polymorphs and crystal orientations. In this Perspective, we highlight the use of nanoporous scaffolds to stabilize high-performing polymorphs of metal-halide perovskites, as well as guide the orientation of organic semiconductor crystals both laterally and vertically for optimized in-plane and out-of-plane charge transport, respectively. Critically, examples of scalable solution-phase deposition methods using nanoporous scaffolds are highlighted as potential targets for commercialization.

show abstract

Direct observation of liquid crystal phases under nanoconfinement: A grazing incidence X-ray diffraction study

Cited by 11 publications

References 40 publications

Orientation Control of Semiconducting Polymers Using Microchannel Molds

Orientation Control of Semiconducting Polymers Using Microchannel Molds

Switchable Plasmonic Film Using Nanoconfined Liquid Crystals

Nanoconfining Optoelectronic Materials for Enhanced Performance and Stability

Contact Info

Product

Resources

About