Hysteresis-free, energy efficient twisted nematic liquid crystal systems based on IB-irradiated gallium-doped tin oxide films

Hae Chang Jeong, Gi Seok Heo, Eun Mi Kim, Hong Gyu Park, Ju Hwan Lee, Jeong Min Han, Dae-Shik Seo

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Abstract: We successfully demonstrated the high performance of liquid crystal (LC) devices without capacitance hysteresis using ion-beam (IB)-irradiated GaSnO in solution. This method is widely used for obtaining inorganic films, although it yields poor crystallinity, owing to its cost effectiveness and high flexibility in combining materials. Atomic force microscopy and X-ray photoelectron spectroscopy analyses determined that IB irradiation on the films had an effect, which enabled the elucidation of the mechanism for LC alignment. Strong IB irradiation on GaSnO induced the formation of spherical particles on the films and rearrangement of the chemical bonds (linkage of Ga–Sn–O and gradually oxidized films), which could preserve the anisotropic characteristics to unidirectionally align LC molecules on the surface. Because rough surfaces effectively increase the electric field, the strongly restructured GaSnO surface led to a decrease in threshold voltages. Moreover, strong IB irradiation effectively released volume charges when the states of LC molecules were switched “on” and “off”, which is attributed to a reduction in oxygen bonding derived from hydroxyl groups responsible for capturing neutral electrons. Therefore, an IB-irradiated GaSnO film is appropriate as an alternative alignment layer for advanced, energy efficient, hysteresis-free LC display devices. Graphical Abstract: We successfully demonstrated the high performance of liquid crystal (LC) devices without capacitance hysteresis using ion-beam (IB)-irradiated GaSnO in solution. This method is widely used for obtaining inorganic films, although it yields poor crystallinity, owing to its cost effectiveness and high flexibility in combining materials. (a) Schematic of the IB irradiation of the solution-derived GaSnO film. (b) Alignment state of the LCs as a function of IB intensity. (c) Transmittance graph using the crystal rotation method to calculate the pretilt angle. (d) Transmittance as a function of voltage of the twisted nematic (TN) cells fabricated from IB-irradiated GaSnO at different intensities compared to the rubbed PI method (e) Capacitance of the TN cells fabricated from IB-irradiated GaSnO at 2200 eV, which exhibited hysteresis-free characteristic of TN cells. Because rough surfaces effectively increase the electric field, the strongly restructured GaSnO surface led to a decrease in threshold voltages. Moreover, strong IB irradiation effectively released volume charges when the states of LC molecules were switched “on” and “off”, which is attributed to a reduction in oxygen bonding derived from hydroxyl groups responsible for capturing neutral electrons. Therefore, an IB-irradiated GaSnO film is appropriate as an alternative alignment layer for advanced, energy efficient, hysteresis-free LC display devices.[Figure not available: see fulltext.]

Original languageEnglish
Pages (from-to)29-36
Number of pages8
JournalJournal of Sol-Gel Science and Technology
Volume79
Issue number1
DOIs
Publication statusPublished - 2016 Jul 1

Fingerprint

Gallium
Nematic liquid crystals
Tin oxides
Ion beams
tin oxides
Free energy
Oxide films
gallium
Hysteresis
oxide films
ion beams
free energy
hysteresis
liquid crystals
Liquid Crystals
Liquid crystals
Irradiation
irradiation
alignment
cost effectiveness

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Chemistry(all)
  • Biomaterials
  • Condensed Matter Physics
  • Materials Chemistry

Cite this

Jeong, Hae Chang ; Heo, Gi Seok ; Kim, Eun Mi ; Park, Hong Gyu ; Lee, Ju Hwan ; Han, Jeong Min ; Seo, Dae-Shik. / Hysteresis-free, energy efficient twisted nematic liquid crystal systems based on IB-irradiated gallium-doped tin oxide films. In: Journal of Sol-Gel Science and Technology. 2016 ; Vol. 79, No. 1. pp. 29-36.
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abstract = "Abstract: We successfully demonstrated the high performance of liquid crystal (LC) devices without capacitance hysteresis using ion-beam (IB)-irradiated GaSnO in solution. This method is widely used for obtaining inorganic films, although it yields poor crystallinity, owing to its cost effectiveness and high flexibility in combining materials. Atomic force microscopy and X-ray photoelectron spectroscopy analyses determined that IB irradiation on the films had an effect, which enabled the elucidation of the mechanism for LC alignment. Strong IB irradiation on GaSnO induced the formation of spherical particles on the films and rearrangement of the chemical bonds (linkage of Ga–Sn–O and gradually oxidized films), which could preserve the anisotropic characteristics to unidirectionally align LC molecules on the surface. Because rough surfaces effectively increase the electric field, the strongly restructured GaSnO surface led to a decrease in threshold voltages. Moreover, strong IB irradiation effectively released volume charges when the states of LC molecules were switched “on” and “off”, which is attributed to a reduction in oxygen bonding derived from hydroxyl groups responsible for capturing neutral electrons. Therefore, an IB-irradiated GaSnO film is appropriate as an alternative alignment layer for advanced, energy efficient, hysteresis-free LC display devices. Graphical Abstract: We successfully demonstrated the high performance of liquid crystal (LC) devices without capacitance hysteresis using ion-beam (IB)-irradiated GaSnO in solution. This method is widely used for obtaining inorganic films, although it yields poor crystallinity, owing to its cost effectiveness and high flexibility in combining materials. (a) Schematic of the IB irradiation of the solution-derived GaSnO film. (b) Alignment state of the LCs as a function of IB intensity. (c) Transmittance graph using the crystal rotation method to calculate the pretilt angle. (d) Transmittance as a function of voltage of the twisted nematic (TN) cells fabricated from IB-irradiated GaSnO at different intensities compared to the rubbed PI method (e) Capacitance of the TN cells fabricated from IB-irradiated GaSnO at 2200 eV, which exhibited hysteresis-free characteristic of TN cells. Because rough surfaces effectively increase the electric field, the strongly restructured GaSnO surface led to a decrease in threshold voltages. Moreover, strong IB irradiation effectively released volume charges when the states of LC molecules were switched “on” and “off”, which is attributed to a reduction in oxygen bonding derived from hydroxyl groups responsible for capturing neutral electrons. Therefore, an IB-irradiated GaSnO film is appropriate as an alternative alignment layer for advanced, energy efficient, hysteresis-free LC display devices.[Figure not available: see fulltext.]",
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Hysteresis-free, energy efficient twisted nematic liquid crystal systems based on IB-irradiated gallium-doped tin oxide films. / Jeong, Hae Chang; Heo, Gi Seok; Kim, Eun Mi; Park, Hong Gyu; Lee, Ju Hwan; Han, Jeong Min; Seo, Dae-Shik.

In: Journal of Sol-Gel Science and Technology, Vol. 79, No. 1, 01.07.2016, p. 29-36.

Research output: Contribution to journalArticle

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T1 - Hysteresis-free, energy efficient twisted nematic liquid crystal systems based on IB-irradiated gallium-doped tin oxide films

AU - Jeong, Hae Chang

AU - Heo, Gi Seok

AU - Kim, Eun Mi

AU - Park, Hong Gyu

AU - Lee, Ju Hwan

AU - Han, Jeong Min

AU - Seo, Dae-Shik

PY - 2016/7/1

Y1 - 2016/7/1

N2 - Abstract: We successfully demonstrated the high performance of liquid crystal (LC) devices without capacitance hysteresis using ion-beam (IB)-irradiated GaSnO in solution. This method is widely used for obtaining inorganic films, although it yields poor crystallinity, owing to its cost effectiveness and high flexibility in combining materials. Atomic force microscopy and X-ray photoelectron spectroscopy analyses determined that IB irradiation on the films had an effect, which enabled the elucidation of the mechanism for LC alignment. Strong IB irradiation on GaSnO induced the formation of spherical particles on the films and rearrangement of the chemical bonds (linkage of Ga–Sn–O and gradually oxidized films), which could preserve the anisotropic characteristics to unidirectionally align LC molecules on the surface. Because rough surfaces effectively increase the electric field, the strongly restructured GaSnO surface led to a decrease in threshold voltages. Moreover, strong IB irradiation effectively released volume charges when the states of LC molecules were switched “on” and “off”, which is attributed to a reduction in oxygen bonding derived from hydroxyl groups responsible for capturing neutral electrons. Therefore, an IB-irradiated GaSnO film is appropriate as an alternative alignment layer for advanced, energy efficient, hysteresis-free LC display devices. Graphical Abstract: We successfully demonstrated the high performance of liquid crystal (LC) devices without capacitance hysteresis using ion-beam (IB)-irradiated GaSnO in solution. This method is widely used for obtaining inorganic films, although it yields poor crystallinity, owing to its cost effectiveness and high flexibility in combining materials. (a) Schematic of the IB irradiation of the solution-derived GaSnO film. (b) Alignment state of the LCs as a function of IB intensity. (c) Transmittance graph using the crystal rotation method to calculate the pretilt angle. (d) Transmittance as a function of voltage of the twisted nematic (TN) cells fabricated from IB-irradiated GaSnO at different intensities compared to the rubbed PI method (e) Capacitance of the TN cells fabricated from IB-irradiated GaSnO at 2200 eV, which exhibited hysteresis-free characteristic of TN cells. Because rough surfaces effectively increase the electric field, the strongly restructured GaSnO surface led to a decrease in threshold voltages. Moreover, strong IB irradiation effectively released volume charges when the states of LC molecules were switched “on” and “off”, which is attributed to a reduction in oxygen bonding derived from hydroxyl groups responsible for capturing neutral electrons. Therefore, an IB-irradiated GaSnO film is appropriate as an alternative alignment layer for advanced, energy efficient, hysteresis-free LC display devices.[Figure not available: see fulltext.]

AB - Abstract: We successfully demonstrated the high performance of liquid crystal (LC) devices without capacitance hysteresis using ion-beam (IB)-irradiated GaSnO in solution. This method is widely used for obtaining inorganic films, although it yields poor crystallinity, owing to its cost effectiveness and high flexibility in combining materials. Atomic force microscopy and X-ray photoelectron spectroscopy analyses determined that IB irradiation on the films had an effect, which enabled the elucidation of the mechanism for LC alignment. Strong IB irradiation on GaSnO induced the formation of spherical particles on the films and rearrangement of the chemical bonds (linkage of Ga–Sn–O and gradually oxidized films), which could preserve the anisotropic characteristics to unidirectionally align LC molecules on the surface. Because rough surfaces effectively increase the electric field, the strongly restructured GaSnO surface led to a decrease in threshold voltages. Moreover, strong IB irradiation effectively released volume charges when the states of LC molecules were switched “on” and “off”, which is attributed to a reduction in oxygen bonding derived from hydroxyl groups responsible for capturing neutral electrons. Therefore, an IB-irradiated GaSnO film is appropriate as an alternative alignment layer for advanced, energy efficient, hysteresis-free LC display devices. Graphical Abstract: We successfully demonstrated the high performance of liquid crystal (LC) devices without capacitance hysteresis using ion-beam (IB)-irradiated GaSnO in solution. This method is widely used for obtaining inorganic films, although it yields poor crystallinity, owing to its cost effectiveness and high flexibility in combining materials. (a) Schematic of the IB irradiation of the solution-derived GaSnO film. (b) Alignment state of the LCs as a function of IB intensity. (c) Transmittance graph using the crystal rotation method to calculate the pretilt angle. (d) Transmittance as a function of voltage of the twisted nematic (TN) cells fabricated from IB-irradiated GaSnO at different intensities compared to the rubbed PI method (e) Capacitance of the TN cells fabricated from IB-irradiated GaSnO at 2200 eV, which exhibited hysteresis-free characteristic of TN cells. Because rough surfaces effectively increase the electric field, the strongly restructured GaSnO surface led to a decrease in threshold voltages. Moreover, strong IB irradiation effectively released volume charges when the states of LC molecules were switched “on” and “off”, which is attributed to a reduction in oxygen bonding derived from hydroxyl groups responsible for capturing neutral electrons. Therefore, an IB-irradiated GaSnO film is appropriate as an alternative alignment layer for advanced, energy efficient, hysteresis-free LC display devices.[Figure not available: see fulltext.]

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