Chiral-nematic liquid crystals as one dimensional photonic materials in optical sensors

Mulder, Dirk J.; Schenning, Aphj Albert; Bastiaansen, Cwm Cees

doi:10.1039/c4tc00785a

Cited by 210 publications

(156 citation statements)

References 35 publications

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“…Likewise, the CLC reflector can be easily designed to match the perovskite emission peak across this range of possible emission colors by changing the concentration of chiral additive 56 . The CLC could also be processed on top of the dielectric 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 stack, removing the need for the Au back reflector and allowing lasing from both ends of the cavity.…”

Section: Toc Graphicsmentioning

confidence: 99%

Enhanced Amplified Spontaneous Emission in Perovskites Using a Flexible Cholesteric Liquid Crystal Reflector

et al. 2015

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Organic-inorganic perovskites are highly promising solar cell materials with laboratory-based power conversion efficiencies already matching those of established thin film technologies. Their exceptional photovoltaic performance is in part attributed to the presence of efficient radiative recombination pathways, thereby opening up the possibility of efficient light-emitting devices. Here, we demonstrate optically pumped amplified spontaneous emission (ASE) at 780 nm from a 50 nm-thick film of CH3NH3PbI3 perovskite that is sandwiched within a cavity composed of a thin-film (∼7 μm) cholesteric liquid crystal (CLC) reflector and a metal back-reflector. The threshold fluence for ASE in the perovskite film is reduced by at least two orders of magnitude in the presence of the CLC reflector, which results in a factor of two reduction in threshold fluence compared to previous reports. We consider this to be due to improved coupling of the oblique and out-of-plane modes that are reflected into the bulk in addition to any contributions from cavity modes. Furthermore, we also demonstrate enhanced ASE on flexible reflectors and discuss how improvements in the quality factor and reflectivity of the CLC layers could lead to single-mode lasing using CLC reflectors. Our work opens up the possibility of fabricating widely wavelength-tunable "mirror-less" single-mode lasers on flexible substrates, which could find use in applications such as flexible displays and friend or foe identification.

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Section: Toc Graphicsmentioning

confidence: 99%

Enhanced Amplified Spontaneous Emission in Perovskites Using a Flexible Cholesteric Liquid Crystal Reflector

et al. 2015

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“…Optical rotation of aqueous solution of AAs can be measured using polarimetry, the oldest technique, and circular dichroism (CD) spectroscopy, a recently developed technique. [33] Recently, Mulder et al [34] summarised the developments in the field of chiral LC-based optical sensors and mentioned that nematic LC doped with a chiral compound and cholesteric LC as photonic materials can respond to organic and water vapour, oxygen, carbon dioxide, metal ions, pH and temperature. In addition, the alliance of Takezoe's group and Abbott's group [35] have investigated the influence of chirality of biomolecules on the alignment of LC at the aqueous/LC interface in 2013.…”

Section: Effect Of Chiral L-and D-aasmentioning

confidence: 99%

Selective and direct detection of free amino acid using the optical birefringent patterns of confined nematic liquid crystals

Wei

Jang

2016

Liquid Crystals

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Detection of amino acid (AA) is an essential step to understand various biological processes. In this study, we used innovative optical birefringent patterns of nematic liquid crystals (LCs) for the detection of several AAs. We attempted to use capillary-confined nematic LCs as sensor for AA analysis because their three-dimensional micro-scale architecture of LCs allowed better performance than that of mainly reported LC thin film sensors owing to the effect on the formation and dynamics of point defect. The sensing system was built by disrupting the alignment of a nematic LC, 4-cyano-4′-pentylbiphenyl (5CB), using the dopant of dodecyl aldehyde. Detection principle is based on the chemical analytical method of aldehyde titration for AAs, wherein the reaction between AAs and aldehyde group generates Schiff bases that could alter the configuration of nematic LCs at the aqueous/LC interface. The patterns generated in the reaction are captured by polarising optical microscopy (POM) and are visible to the naked eye. The functionalised LCs detected glycine at concentrations as low as 1 pM. There was a surprising result that it can selectively detect D-AAs against their L-isomers, however, further efforts are required to explain the mechanism.ARTICLE HISTORY

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“…2 With the change in wavelength of maximum reectance, the color changes depending on the thickness and associated RI caused by an ex-stimulus. Many efforts have been devoted for implementing functionality within 1DPC by the bottom-up assembly of tailor-made inorganic or hybrid materials, such as dielectric and conductive metal oxides, 4-7 sol-gel-based materials, [8][9][10] zeolites, 11 clays, [12][13][14] super-paramagnetic colloidal particles, 15,16 liquid crystals, 17,18 organic polymers, [19][20][21] and hydrogels. These features make 1DPCs excellent platforms for a variety of physical, chemical, and biological sensors.…”

Section: Introductionmentioning

confidence: 99%

Flexible metal–organic framework-based one-dimensional photonic crystals

Tao

Wang

et al. 2015

J. Mater. Chem. C

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A flexible metal-organic framework (MOF)-based one-dimensional photonic crystal (1DPC) was fabricated by a spin-coating method. The flexible MOF, NH 2 -MIL-88B (MIL ¼ Materials from Institute Lavoisier), was selected and implanted as the intrinsic functional layer of 1DPCs because of its selective breathing behavior upon exposure to various guests. TiO 2 nanoparticles were used as another component to ensure a high refractive index contrast. The optical properties of the 1DPCs were tailored by varying the number of bilayers, incident angles, and physical thickness of the individual slabs. The fabricated 1DPCs showed a selective response toward various organic vapors as a result of the selective breathing behavior of the NH 2 -MIL-88B layer. Selective quantitative measurements of the ethanol concentrationwere achieved when the 1DPC was exposed to the vapors of an ethanol and water mixture. The fabricated 1DPCs exhibited high long-term, thermal, and mechanical stability, which are beneficial for practical applications. 84574241 † Electronic supplementary information (ESI) available: Characterization of NH 2 -MIL-88B and TiO 2 nanoparticles, optical responses of 1DPC upon various organic vapors, photographs of 1DPC aer high thermal, long term and ultrasonic treatments. See

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Chiral-nematic liquid crystals as one dimensional photonic materials in optical sensors

Cited by 210 publications

References 35 publications

Enhanced Amplified Spontaneous Emission in Perovskites Using a Flexible Cholesteric Liquid Crystal Reflector

Enhanced Amplified Spontaneous Emission in Perovskites Using a Flexible Cholesteric Liquid Crystal Reflector

Selective and direct detection of free amino acid using the optical birefringent patterns of confined nematic liquid crystals

Flexible metal–organic framework-based one-dimensional photonic crystals

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