Effect of dye on electro-optic behavior of vertically aligned liquid crystal display cell

Chinky,; Dogra, Ankit Rai; Sharma, Vandna; Gahrotra, Ridhima; Malik, Praveen; Kumar, Pankaj

doi:10.1063/5.0001815

Cited by 9 publications

(3 citation statements)

References 14 publications

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“…Out of the used dyes, azo dye proves most commonly used dye for fabricating this kind of LC displays due to their properties compatible to the LCs. The azo dye molecules have extended and rod-like molecular shape and are more suitable to get aligned with the LC host [20][21][22][23][24][25]. Thus, in the present work, a dye doped vertically aligned LC (VALC) cell was formed by mixing 0.125% of azo dye in host LC-ZnO NPs mixture.…”

Section: Introductionmentioning

confidence: 99%

Effect of Azo Dye on Electro-Optic and Optical Band Gap Characteristics in ZnO Nanoparticles Induced Vertically Aligned Liquid Crystal Cells

Jaggi,

Kumar,

Malik

2023

J. Phys.: Conf. Ser.

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Alignment of liquid crystal (LC) molecules in vertical direction is the most promising and interesting aspect for display devices in view of scientific and technological growth. Moreover, in accordance with the photovoltaic device applications, liquid crystals (LCs) show numerous applications. In the present work, the impact of dye as dopant with appropriate amount, over the electro-optic (E-O) and band gap properties as well as phase behaviour of vertically aligned liquid crystals (VALCs) has been studied and discussed. Initially, zinc oxide (ZnO) nanoparticles (NPs) were mixed to induce the vertical alignment (VA) in confined cell. Then, to prepare the dye doped LC sample, 0.125% of azo dye as dopant was uniformly mixed in the host sample. The results showed enhanced E-O characteristics with reduction in optical band gap as calculated using UV Visible study in 0.125% dye doped cell as compared to host sample cell.

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Section: Introductionmentioning

confidence: 99%

Effect of Azo Dye on Electro-Optic and Optical Band Gap Characteristics in ZnO Nanoparticles Induced Vertically Aligned Liquid Crystal Cells

Jaggi,

Kumar,

Malik

2023

J. Phys.: Conf. Ser.

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“…The Liquid crystals (LCs) and display devices are widely used in today's life due to various uses like high degree of resolution, low energy utilization and slimness [1][2][3][4][5][6][7][8]. Among different modes used for the alignment of LC molecules, VA mode has considerably improved morphological and E-O characteristics because LC molecules are vertically aligned w.r.t the substrate surface [9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Studies of Electro-Optic and Thermal Behaviour of Azo Dye Doped Vertically Aligned Liquid Crystal

Jaggi¹,

Kumar²,

Malik³

2022

ECS Trans.

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The performance of liquid crystal (LC) display devices significantly depends on the usage of an optimized concentration of dopant. Thus, in the present study, vertically aligned liquid crystals (VALCs) display cells were prepared using dispersion of zinc oxide (ZnO) nano particles into host nematic liquid crystal (NLC) without any surface treatment. Further, the sample mixture was doped with fixed concentration of 0.5% of azo dye. Both the sample cells were analyzed and compared for morphological, electro-optical (E-O) and thermal behaviour. Results show the improvement in voltage-transmittance characteristics with lowering of threshold and operating voltage, however the contrast ratio (CR) for dye doped sample cell was found to be degraded. This degradation may be possibly due to much lower transition temperature at this concentration of dye, which further might because of higher OFF state and lesser ON state transmittance due to disturbance in intrinsic LC order. As, the thermal study showed the doping of 0.5% of azo dye reduced the transition temperature to 410 for dye doped VALC from 680 of VALC sample. Hence, these results indicate that a control amount of dichroic dye is a crucial measure for an adequate performance of VALC display.

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“…In recent reports, authors mentioned that the Si-based semiconductor devices has been overtaken globally by the LCD device market (7)(8)(9). Generally, in case of traditional LCDs, to achieve the uniform alignment of LCs, rubbed 'parallel alignment layer' is adopted, however, due to these layers some defects such as, low contrast ratio, narrow viewing angle and slower response time etc (10)(11)(12)(13)(14) in the display devices are seen. Nevertheless, the homeotropic alignment (HA) based LCDs can improve the performance by removing these defects up to greater extent.…”

Section: Introductionmentioning

confidence: 99%

Thickness Dependent Electro-Optical Behaviour of Homeotropically Aligned Nematic Liquid Crystal

Dogra¹,

Sharma²,

Gahrotra³

et al. 2022

ECS Trans.

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The homeotropically aligned liquid crystal (LC) display devices are of great interest in recent time. Thus, in the present work, the thickness dependent electro-optical behaviour of nematic liquid crystal (NLC) in homeotropic alignment (HA) has been studied. To achieve the HA of NLC, polyimide (PI) coated ITO glass substrates were used. Consequently, cleaned ITO glass substrates (with thickness of 0.7 mm) were used for the fabrication of the LC cells. The pure NLC material (LC-BYVA) was filled into PI coated cells by the capillary injection method. Subsequently, the filled cells were examined with the help of polarized optical microscope (POM), which show the good dark and bright orthoscopic textures of NLC in field ON and OFF states, respectively under cross-polarizers. The conoscopic study of the images also confirmed the perfect HA of NLC molecules. The dark states change to good bright state with the change in orientation of NLC director from homeotropic to planar at operating voltages as seen under cross-polarizers. The electro-optical (E-O) study also shows the good contrast ratio (CR) of display cells.

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Effect of dye on electro-optic behavior of vertically aligned liquid crystal display cell

Cited by 9 publications

References 14 publications

Effect of Azo Dye on Electro-Optic and Optical Band Gap Characteristics in ZnO Nanoparticles Induced Vertically Aligned Liquid Crystal Cells

Effect of Azo Dye on Electro-Optic and Optical Band Gap Characteristics in ZnO Nanoparticles Induced Vertically Aligned Liquid Crystal Cells

Studies of Electro-Optic and Thermal Behaviour of Azo Dye Doped Vertically Aligned Liquid Crystal

Thickness Dependent Electro-Optical Behaviour of Homeotropically Aligned Nematic Liquid Crystal

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