Influence of rubbing-alignment on microwave modulation induced by liquid crystal

Ye, Wenjiang; Xing, Hongyan; Zhou, Xuan; Sun, Yubao; Zhang, Zhidong

doi:10.1063/1.4922960

Cited by 8 publications

(2 citation statements)

References 23 publications

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“…The rubbing technique is commonly used to anchor nematic liquid crystals in a desired orientation. 41,42 This manufacturing approach has excellent advantages, such as the capability of large-scale applications, processability at room temperature and normal pressure conditions, and is a simple and low-cost method. The nRRS-inserted OLEDs exhibited enhanced performance owing to the light scattering effect.…”

Section: Introductionmentioning

confidence: 99%

Enhancing the optical performance of organic light-emitting diodes using nanoscale random rubbed structure

Shin

Lee

Choi

et al. 2022

Nanomaterials and Nanotechnology

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In this study, we evaluated a nanoscale random rubbed structure (nRRS) used as a scattering layer in organic light-emitting diodes (OLEDs) through an innovative manufacturing method. The rubbing technique, which is conventionally utilized only for liquid crystal alignment, is a manufacturing process with excellent merit in that it can form nanoscale random corrugation in a large area without vacuum equipment even at room temperature, and it is simple and inexpensive. The optimized nRRS, fabricated via rubbing, exhibited a high transmittance of 97.8% and haze of 17.8%, making it suitable as a scattering layer for OLEDs. Owing to its random nature, the scattering effect occurred effectively by rearranging the waveguided light inside the glass substrate. The OLED combined with the optimized nRRS showed a 25.4% improvement in the external quantum efficiency. Additionally, the spectral distortion according to the viewing angle was alleviated, which was confirmed by the negligible difference in the International Commission on Illumination 1931 color space coordinates (∆(x, y) = (0.01, 0.013)). The optical performance of the nRRS–OLED was predicted through a finite-difference time-domain simulation and verified by showing results consistent with those of the fabricated device. This research is expected to be widely applied in many optical devices because it is possible to form a random corrugation on the outside of the device without the difficulty of simply fabricating a beneficial optical structure.

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Section: Introductionmentioning

confidence: 99%

Enhancing the optical performance of organic light-emitting diodes using nanoscale random rubbed structure

Shin

Lee

Choi

et al. 2022

Nanomaterials and Nanotechnology

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“…At present, several LC display and nondisplay devices are based on weak anchoring. [3][4][5][6][7][8][9] Therefore, the precise determination of anchoring energy on the substrate surface can ensure the accurate design of LC devices.…”

Section: Introductionmentioning

confidence: 99%

Experimental design to measure the anchoring energy on substrate surface by using the alternating-current bridge

Hao¹,

Liu²,

Zhang³

et al. 2017

Chinese Phys. B

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The anchoring property of the substrate surface of liquid crystal cells plays an important role in display and nondisplay fields. This property directly affects the deformation of liquid crystal molecules to change the phase difference through liquid crystal cells. In this paper, a test method based on the alternating-current bridge is proposed to determine the capacitance of liquid crystal cells and thus measure the anchoring energy of the substrate surface. The anchoring energy can be obtained by comparing the capacitance-voltage curves of twisted nematic liquid crystal cells with different anchoring properties in experimental and theoretical results simulated on the basis of Frank elastic theory. Compared with the other methods to determine the anchoring energy, our proposed method requires a simple treatment of liquid crystal cells and allows easy and high-accuracy measurements, thereby expanding the test ideas on the performance parameters of liquid crystal devices.

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Liquid‐Crystal High‐Frequency Microwave Technology: Materials and Characterization

Zografopoulos

Ferraro

Beccherelli

2018

Adv Materials Technologies

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Ever since the advent of microwave technology, tunable devices, such as phase shifters, resonators, and antennas, have been indispensable in applications requiring radiofrequency signal filtering, beam shaping, or steering. This necessity becomes even more relevant in view of a new era in high‐bandwidth wireless communications in 5G networks, satellite links, and advanced radars for sensing and safety. As the operating frequency is pushed toward the millimeter‐wave range or beyond, the performance of traditional microwave tunable elements, such as PIN diodes, micro‐electromechanical system switches, ferrites, or ferroelectric films, degrades, while their fabrication complexity and cost increases. In this respect, liquid crystals present a promising solution, as they provide continuous tuning, low dielectric constants, moderate losses, low dispersion, and potentially low cost. Here, a comprehensive overview of the available microwave liquid crystal materials is provided, including their key application‐relevant properties, and the techniques employed for their characterization, focusing on the spectrum above 1 GHz. Their performance metrics in terms of dielectric constant tunability, response speed, insertion losses are discussed and guidelines for their selection in different microwave applications are provided. Moreover, the differences observed in the experimental data regarding their characterization are highlighted and possible sources of the observed discrepancies are discussed.

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Influence of rubbing-alignment on microwave modulation induced by liquid crystal

Cited by 8 publications

References 23 publications

Enhancing the optical performance of organic light-emitting diodes using nanoscale random rubbed structure

Enhancing the optical performance of organic light-emitting diodes using nanoscale random rubbed structure

Experimental design to measure the anchoring energy on substrate surface by using the alternating-current bridge

Liquid‐Crystal High‐Frequency Microwave Technology: Materials and Characterization

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