Photo-responsive dye-doped liquid crystals for smart windows

Talukder, Javed Rouf; Lee, Yun‐Han; Wu, Shin‐Tson

doi:10.1364/oe.27.004480

Cited by 48 publications

(27 citation statements)

References 25 publications

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“…Dye-doped LC have found numerous applications in smart window for light-tuning and privacy protection. A lot of related research have been carried out [1][2] [3]. In addition to the light absorption dye-doped LC, polymer-stabilized LC(PDLC) [4] and polymerdispersed LC(PSLC) [5] based on light-scattering effect have been developed.…”

Section: Introductionmentioning

confidence: 99%

P‐82: Dichroic Dye‐Doped Dual‐Cell Smart Window Switchable Among Transparent, Dark and Scattering States

Zhou

Che

et al. 2021

Symp Digest of Tech Papers

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The paper introduces a dual‐cell smart window based on dichroic dyed‐doped liquid crystal. To promote light absorption, the rubbing directions of coated PI in each cell are made perpendicular to each other. Due to the crossed‐polarizer structure, very low transmittance of light is achieved. By varying the amplitude and frequency of the driving voltage, the window can be smoothly switched among transparent, dark and scattering states. Regular structures formed by the distortions of LC is observed through a thin film polarizer. At last, one cell working in light absorption mode while the other in dynamic scattering mode is demonstrated.

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Section: Introductionmentioning

confidence: 99%

P‐82: Dichroic Dye‐Doped Dual‐Cell Smart Window Switchable Among Transparent, Dark and Scattering States

Zhou

Che

et al. 2021

Symp Digest of Tech Papers

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“…As is well known, cholesteric LCs (CLCs) with self‐organized helical superstructures have received a great deal of attention owing to their unique optical property like selective light reflection and helical pitch sensitive to the impact of the external environment such as electric field, temperature, light, and so on. [ 12,13 ] Recently, our group has developed various of light‐responsive emissive CLCs by doping with chiral fluorescent photoswitches into the nematic LCs. [ 14 ] However, achieving a large‐scale fluorescence color switching in the photoresponsive emissive CLCs remains a challenge.…”

Section: Introductionmentioning

confidence: 99%

Phototuning Energy Transfer in Self‐Organized Luminescent Helical Superstructures for Photonic Applications

Lin

Sun

Qiao

et al. 2020

Advanced Optical Materials

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Stimuli‐triggered changes in the emission color of functional materials are in demand for a variety of potential applications. Herein, a strategy to reversibly phototune fluorescence color in cholesteric liquid crystal (CLC) with self‐organized luminescent helical superstructure via fluorescence resonance energy transfer (FRET) is developed. This dynamic FRET system is constructed by doping with 1,2‐dithienyldicyanoethene‐based chiral fluorescent photoswitch (switch 7) as an acceptor and a conventional coumarin dye C6 as a donor into a nematic liquid crystal (LC) host. The efficient energy transfer from C6 to switch 7 in the LC media, which is evidenced by both of emission color shift and enhanced circularly polarized luminescence, can be modulated on the basis of reversible trans–cis photoisomerization of switch 7 upon visible/UV light irradiations, leading to the emission color change from orange to green. Noteworthily, the FRET efficiency can be significantly improved when CLCs are confined in the polymer microtubes. Preliminary demonstrations of the LC film and LC microtubes array for information display and encryption with ease of electrical operation between planar, homeotropic, and focal conic states or light manipulation are described.

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“…The advantage of a photo-controllable liquid crystal smart window is that it can automatically adjust transmittance from high to low upon exposure to UV, as in sunlight, and so self-adjust without extra energy input. The photo-controllable liquid crystal smart window requires additional photo-sensitive material (such as photosensitive chiral azobenzene [14,15], photochromic dye [16], or azo dye [17]). Most of the photo-controlled liquid crystal smart windows perform the sole function of either absorption or scattering.…”

Section: Introductionmentioning

confidence: 99%

Smart Window with Active-Passive Hybrid Control

et al. 2020

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Dimming and scattering control are two of the major features of smart windows, which provide adjustable sunlight intensity and protect the privacy of people in a building. A hybrid photo- and electrical-controllable smart window that exploits salt and photochromic dichroic dye-doped cholesteric liquid crystal was developed. The photochromic dichroic dye causes a change in transmittance from high to low upon exposure to sunlight. When the light source is removed, the smart window returns from colored to colorless. The salt-doped cholesteric liquid crystal can be bi-stably switched from transparent into the scattering state by a low-frequency voltage pulse and switched back to its transparent state by a high-frequency voltage pulse. In its operating mode, an LC smart window can be passively dimmed by sunlight and the haze can be actively controlled by applying an electrical field to it; it therefore exhibits four optical states—transparent, scattering, dark clear, and dark opaque. Each state is stable in the absence of an applied voltage. This smart window can automatically dim when the sunlight gets stronger, and according to user needs, actively adjust the haze to achieve privacy protection.

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Photo-responsive dye-doped liquid crystals for smart windows

Cited by 48 publications

References 25 publications

P‐82: Dichroic Dye‐Doped Dual‐Cell Smart Window Switchable Among Transparent, Dark and Scattering States

P‐82: Dichroic Dye‐Doped Dual‐Cell Smart Window Switchable Among Transparent, Dark and Scattering States

Phototuning Energy Transfer in Self‐Organized Luminescent Helical Superstructures for Photonic Applications

Smart Window with Active-Passive Hybrid Control

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