Fundamental properties of light-emitting liquid crystal cells operated under alternating voltage

Honma, Mareki; Horiuchi, Takao; Nose, Toshiaki

doi:10.1063/1.4817173

Cited by 3 publications

(2 citation statements)

References 31 publications

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“…7 Improving methods for the ECL performance of the rubrene-based cells have been investigated by many researchers. [8][9][10][11][12][13] In 2001, Nishimura et al demonstrated a bright yellow emission of rubrene with a maximum luminance (L max ) of 183 cd m ¹2 at a direct current (DC) voltage of 8 V. 12 In their study, the ECL solution was prepared by dissolving rubrene with 1,2-diphenoxyethane (DPE) as an ion conductive assist dopant in a mixed solvent of acetonitrile (ACN) and 1,2dichlorobenzene (1,2-DCB). In 2021, Kim et al evaluated the ECL performance of rubrene dissolved in a tetrahydrofuran (THF) solvent under an alternating current (AC) voltage, and an L max of over 30 cd m ¹2 was observed at a frequency of 60 Hz.…”

Section: Introductionmentioning

confidence: 99%

Bright Yellow Electrogenerated Chemiluminescence Cell Using a Rubrene Solution Doped with an Emitting Assist Dopant

et al. 2023

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We demonstrated that the electrogenerated chemiluminescence (ECL) performances of 5,6,11,12-tetraphenyltetracene (rubrene)-based devices can be significantly enhanced by using an emitting assist dopant. We prepared an ECL solution by dissolving rubrene and 4-(di-p-tolylamino)-4′-[(di-p-tolylamino)styryl]stilbene (DPAVB) in an organic solvent. A microfluidic ECL cell having the prepared solution exhibited a bright yellow ECL emission from rubrene with a maximum luminance of 292 cd m −2 at 6.0 V and a maximum current efficiency of 4.50 cd A −1 at 5.5 V. Moreover, a current efficiency of over 3.0 cd A −1 was maintained from 3.0 to 6.5 V. Furthermore, the device lifetime was improved in comparison with the rubrene solution without DPAVB. The emission mechanism was discussed using cyclic voltammogram data. The DPAVB molecule was found to be more readily oxidized and more difficult to be reduced than rubrene. The excited rubrene molecules were expected to be produced efficiently in the device by the electron transfer reactions between rubrene •− and DPAVB •+ as well as rubrene •− and rubrene •+ . Based on the findings, we concluded that the enhanced device characteristics were primarily attributed to the well-balanced generation of radical cations and anions.

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Section: Introductionmentioning

confidence: 99%

Bright Yellow Electrogenerated Chemiluminescence Cell Using a Rubrene Solution Doped with an Emitting Assist Dopant

et al. 2023

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“…14) Luminance greater than 100 cd/cm 2 was achieved by introducing an appropriate heated stirring process during rubrene dissolution. 14) Fur-thermore, we have recently reported that carrier transport is mainly governed by ionic conduction 20,21) and device operation; however, it exhibits properties of both electrochemiluminescent (ECL) devices and organic light-emitting diodes (OLEDs). 22) That is, the luminance depends on the emission layer thickness, as is true for OLEDs, although conventional ECL devices exhibit a weak dependence on the thickness.…”

Section: Introductionmentioning

confidence: 99%

Influence of hole injection layer and work function of cathode on the performance of light-emitting liquid crystal cells with fluorescent dye-doped nematic liquid crystal

Honma

Horiuchi

Watanabe

et al. 2014

Jpn. J. Appl. Phys.

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We investigated the properties of rubrene-doped nematic-liquid-crystal cells to help determine the appropriate structure and material of electrodes for inducing light emission. In particular, we addressed the influence of the insertion of a hole injection layer (HIL) and the work function of the cathode on device performance. As a result, the employment of a HIL and a lower-work-function material was revealed to be effective in obtaining higher luminance and external quantum efficiency. We concluded that this improvement is caused by the facilitated carrier injection on the HIL and cathode surface, as is true for common organic light-emitting diodes.

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Diastereomeric Effect on Bulk Photovoltaic Property and Polarized Electroluminescence in Ferroelectric Liquid Crystals Containing an Extended π-Conjugated Unit

Matoba

Uemura

Funahashi

2023

Bulletin of the Chemical Society of Japan

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We synthesized two diastereomers comprising the same π-conjugated unit. One diastereomer exhibited a smectic crystal phase in which the chromophores tilted 45 degrees from the layer normal and macroscopic polarization was induced by a DC bias application in a cooling process from the high temperature phase to the smectic crystal phase. The other diastereomer exhibited a smectic crystal phase in which the chromophores were parallel to the layer normal and macroscopic polarization was not induced. The bulk photovoltaic effect and polarization-induced electroluminescence were observed only in the polarized smectic crystal phase in which the chromophores tilted from the layer normal. In the bulk photovoltaic effect in the tilted smectic crystal phase doped with fullerene derivative, the open circuit voltage and short circuit current were 1.03 V and 100 µAcm−2 for white light illumination (20 mWcm−2), respectively. In the polarization-induced electroluminescence in the tilted smectic crystal phase, linearly polarized emission with the dichroic ratio exceeding 10 was obtained and the axis of the linearly polarized emission could be rotated 90 degrees by an inversion of a DC bias of poling treatment.

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Fundamental properties of light-emitting liquid crystal cells operated under alternating voltage

Cited by 3 publications

References 31 publications

Bright Yellow Electrogenerated Chemiluminescence Cell Using a Rubrene Solution Doped with an Emitting Assist Dopant

Bright Yellow Electrogenerated Chemiluminescence Cell Using a Rubrene Solution Doped with an Emitting Assist Dopant

Influence of hole injection layer and work function of cathode on the performance of light-emitting liquid crystal cells with fluorescent dye-doped nematic liquid crystal

Diastereomeric Effect on Bulk Photovoltaic Property and Polarized Electroluminescence in Ferroelectric Liquid Crystals Containing an Extended π-Conjugated Unit

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