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Search for "liquid crystal" in Full Text gives 49 result(s) in Beilstein Journal of Nanotechnology.
Influence of magnetic domain walls on all-optical magnetic toggle switching in a ferrimagnetic GdFe film
Beilstein J. Nanotechnol. 2022, 13, 74–81, doi:10.3762/bjnano.13.5
- central wavelength of 800 nm were focused on the sample at a grazing incidence of 16° to a spot size of about 12 × 60 μm2 (at 1/e of the maximum intensity) by a lens inside the vacuum chamber. The combination of a polarizer and a half-wave liquid crystal plate constitutes a variable attenuator for tuning
Sputtering onto liquids: a critical review
Beilstein J. Nanotechnol. 2022, 13, 10–53, doi:10.3762/bjnano.13.2
Assessment of the optical and electrical properties of light-emitting diodes containing carbon-based nanostructures and plasmonic nanoparticles: a review
Beilstein J. Nanotechnol. 2021, 12, 1078–1092, doi:10.3762/bjnano.12.80
- market. Light sources in OLED mainly consist of Alq3 and derived version of PPV polymer, whereas QD based on Cd, Zn, Se, and S are mainly used for QLED. Both technologies have many advantages over traditional inorganic LED and liquid crystal displays in terms of low power consumption, wider view angle
Paper-based triboelectric nanogenerators and their applications: a review
Beilstein J. Nanotechnol. 2021, 12, 151–171, doi:10.3762/bjnano.12.12
- generally stored in energy storage devices first. This can be performed by using a bridge rectifier and different types of capacitors. The charged capacitor is then used to power the target electronic devices, such as segmented LED display, liquid crystal display (LCD), and electroluminescence (EL) display
A review on the green and sustainable synthesis of silver nanoparticles and one-dimensional silver nanostructures
Beilstein J. Nanotechnol. 2021, 12, 102–136, doi:10.3762/bjnano.12.9
- devices [94], organic light emitting diodes (OLED) [95], transparent conductive electrodes [96][97], artificial skin [98], liquid crystal display (LCD) [99][100], and smart windows [101][102]. AgNWs can be embedded in flexible touch-screen substrates and electronic displays to provide an enhanced decrease
An advanced structural characterization of templated meso-macroporous carbon monoliths by small- and wide-angle scattering techniques
Beilstein J. Nanotechnol. 2020, 11, 310–322, doi:10.3762/bjnano.11.23
- temperatures between 350 and 500 °C and forms a liquid-crystal-like state, the lower viscosity of which prevents the formation of closed voids [15]. By contrast, SANS analysis of the empty resin probe (800 °C) provides an average pore size of ca. 1 nm, which is substantially smaller than the average pore size
Liquid crystal tunable claddings for polymer integrated optical waveguides
Beilstein J. Nanotechnol. 2019, 10, 2163–2170, doi:10.3762/bjnano.10.209
- explored. Tunable waveguides have been modeled and fabricated using polymers. Optical functions such as variable coupling and optical switching have been demonstrated. Keywords: liquid crystal; organic waveguide; photonic integrated circuit; polymer waveguide; tunable cladding; Introduction Photonic
- thickness is significantly reduced. In this case, a working range for optical switches can be found. Two waveguides at short distance interacting through evanescent fields. The interaction is tuned by the liquid crystal acting as cladding. Acknowledgements Authors are indebted for financial support to
Precise local control of liquid crystal pretilt on polymer layers by focused ion beam nanopatterning
Beilstein J. Nanotechnol. 2019, 10, 1691–1697, doi:10.3762/bjnano.10.164
- alignment of rubbed polymer layers can be locally flipped to vertical by irradiation with a focused ion beam on a scale of tens of nanometers. Results: We propose a digital method to precisely steer the liquid crystal director tilt at polymer surfaces by combining micrometer-size areas treated with focused
- ion beam and pristine areas. The liquid crystal tends to average the competing vertical and planar alignment actions and is stabilized with an intermediate pretilt angle determined by the local pattern duty factor. In particular, we create micrometer-sized periodic stripe patterns with this factor
- gradually varying from 0 to 1. Our optical studies confirm a predictable alignment of a nematic liquid crystal with the pretilt angle continuously changing from 0° to 90°. A one-constant model neglecting the difference between the elastic moduli reproduces the results quantitatively correctly. Conclusion
Magnetic segregation effect in liquid crystals doped with carbon nanotubes
Beilstein J. Nanotechnol. 2019, 10, 1464–1474, doi:10.3762/bjnano.10.145
- study the orientational transitions in a suspension of carbon nanotubes in a nematic liquid crystal induced by an external magnetic field. The case of a finite orientational anchoring of liquid crystal molecules at the surface of doped carbon nanotubes is considered. It is shown that in a magnetic field
- the initial homogeneous planar texture of the liquid crystal–carbon nanotubes mixture is disturbed in a threshold manner (Fréedericksz transition). The orientational and concentration distributions of the suspension are studied for different values of the magnetic field strength and segregation
- intensity of the impurity subsystem. The optical phase lag between ordinary and extraordinary rays of light transmitted through a layer of a liquid crystal composite is calculated. The possibility of changing the nature of the Fréedericksz transition from second order to first order is shown. This
Highly ordered mesoporous silica film nanocomposites containing gold nanoparticles for the catalytic reduction of 4-nitrophenol
Beilstein J. Nanotechnol. 2019, 10, 1368–1379, doi:10.3762/bjnano.10.135
- structure, templated by the discotic liquid crystal of [Au3Pz3]C10TEG [25], with orientation parallel to the substrate [38]. By using Bragg’s law, the interpore distance of the hexagonal structure at 2θ = 2.2° was found to be 4.1 nm, which is close to the calculated molecular size of the complex with the
Nanoscale optical and structural characterisation of silk
Beilstein J. Nanotechnol. 2019, 10, 922–929, doi:10.3762/bjnano.10.93
- crystalline segments in the silk fiber. SNOM measurements are well suited to measure n and κ from areas of comparable dimensions. Silk is a strongly birefringent material, as revealed by cross-polarised optical imaging (Figure 3). The images were taken following adjustments of the voltage of a liquid crystal
- = 0.25. (a) A series of optical images taken at different voltages of a liquid crystal (LC) retarder (schematically shown in the inset of (b)) and a Nikon Optiphot-pol microscope with LMPlanFL 20× objective lens, NA = 0.4. (b) Calibration curve of retardance as a function of voltage collected at 635 nm
Threshold voltage decrease in a thermotropic nematic liquid crystal doped with graphene oxide flakes
Beilstein J. Nanotechnol. 2019, 10, 71–78, doi:10.3762/bjnano.10.7
- /bjnano.10.7 Abstract We report a threshold voltage decrease in a nematic liquid crystal compound, 4-cyano-4′-pentylbiphenyl (5CB), doped with graphene oxide (GO) flakes at a concentration of 0.05–0.3 wt %. The threshold voltage decrease was observed at the same concentration in electro-optic and
- presence of the electric field was discussed. Keywords: graphene oxide; liquid crystal; nematic phase; switching; threshold voltage; Introduction Liquid crystals (LCs) are classified as a type of soft matter which are characterized by anisotropic molecules and a liquid-like fluidity behavior. Of all LC
- phases, special attention is paid to the nematic liquid crystal (NLC) phase because is widely used in many electro-optical applications [1][2]. In the uniaxial nematic phase, the direction of the optical axis is described by the director n, which is the unit vector along the molecular axis. An applied
Zn/F-doped tin oxide nanoparticles synthesized by laser pyrolysis: structural and optical properties
Beilstein J. Nanotechnol. 2019, 10, 9–21, doi:10.3762/bjnano.10.2
- commercial applications that require both transparency and electrical conductivity (employed in liquid crystal displays, organic light emitting diodes (OLEDs), touchscreens or in solar panels) is indium tin oxide (ITO), which unfortunately suffers from high cost and a limited supply of indium [5]. One
Nanostructured liquid crystal systems and applications
Beilstein J. Nanotechnol. 2018, 9, 2644–2645, doi:10.3762/bjnano.9.245
- having numerous applications in liquid crystal displays, modulators, sensors, solar cells, etc. Liquid crystals are used in both large and small devices. They surround us everywhere: in our house, on the street, and at our job. Liquid crystals are applied in biology and medicine, and for oil recovery as
- well as in food production. The molecules of the human body (e.g., DNA, proteins) can also form liquid crystal phases. Many applications of liquid crystals require the manipulation of structures on the nanometer scale. For example, these highly sensitive materials are capable of changing their
- structure on the nanoscale level for detection of small fractions of dopant materials. In this respect, much attention has been paid to the investigation of liquid crystal droplets dissolved in liquid, in particular, to the photoinduced orientation of liquid crystal molecules at the surface of a droplet
Nanocellulose: Recent advances and its prospects in environmental remediation
Beilstein J. Nanotechnol. 2018, 9, 2479–2498, doi:10.3762/bjnano.9.232
- et al. [59] has synthesized a highly efficient filter membrane for oil/water separation by combining super hydrophilic tunicate cellulose nanocrystal and cholesteric liquid crystal structure. The tunicate cellulose was derived from Halocynthia roretzi drasche, also known as the sea pineapple. In
Dumbbell gold nanoparticle dimer antennas with advanced optical properties
Beilstein J. Nanotechnol. 2018, 9, 2188–2197, doi:10.3762/bjnano.9.205
- radially polarized beam by means of a liquid crystal mode converter (ArcOptics, Switzerland) which is coupled to an inverse microscope (Ti-U, Nikon, Japan) and is tightly focussed with a high NA objective (100× Plan APO, NA 1.49, Nikon, Japan) to the tip–sample region. The emitted fluorescence signal is
Photoluminescence of CdSe/ZnS quantum dots in nematic liquid crystals in electric fields
Beilstein J. Nanotechnol. 2018, 9, 1544–1549, doi:10.3762/bjnano.9.145
- , Russia 10.3762/bjnano.9.145 Abstract We have experimentally investigated the effect of the reorientation of a nematic liquid crystal (LC) in an electric field on the photoluminescence (PL) of CdSe/ZnS semiconductor quantum dots (QDs). To the LC with positive dielectric anisotropy, 1 wt % QDs with a core
- obtained results are interesting for controlling the PL intensity of semiconductor QDs in liquid crystals by the application of electric fields. Keywords: aggregation; decay time; liquid crystal; luminescence intensity; orientation; Introduction Colloidal quantum dots (QDs) are a special kind of
- significantly changes their optical properties [6][7][8][9][10]. To control the properties of NPs, they are introduced into a passive or active matrix interacting with them. Liquid crystals can be an active matrix for NPs. The dielectric and optical properties of a liquid crystal (LC) vary under electromagnetic
Induced smectic phase in binary mixtures of twist-bend nematogens
Beilstein J. Nanotechnol. 2018, 9, 1297–1307, doi:10.3762/bjnano.9.122
- , Croatia Institute of Chemistry, Physical Chemistry, Martin Luther University Halle-Wittenberg, von-Danckelmann-Platz 4, 06120 Halle, Germany 10.3762/bjnano.9.122 Abstract The investigation of liquid crystal (LC) mixtures is of great interest in tailoring material properties for specific applications. The
- in controlling the self-organizing processes. Keywords: binary mixture; liquid crystals; smectic phase induction; temperature-dependent FTIR; twist-bend nematogen; Introduction Nowadays liquid crystal (LC) substances possess a wide range of uses. However, it is rather rare that a single organic
- ]. Apart from shifting the phase transition temperatures in the mixtures of two LC compounds, the formation of a new mesophase is also an interesting phenomenon. The first induced mesophase was discovered in binary rod-like nematic liquid crystal mixtures of N-(p-methoxybenzylidene)-p-n-butylaniline (MBBA
Formation and development of nanometer-sized cybotactic clusters in bent-core nematic liquid crystalline compounds
Beilstein J. Nanotechnol. 2018, 9, 1288–1296, doi:10.3762/bjnano.9.121
- , enabling this finding to be used in practical devices. The molecular structure and phase transitions of two bent-core liquid crystal samples: BCN66 (m = n = 6): Cr 55 °C [37.1] NcybC 101 °C [0.5] Iso [52] and BCN84 (m = 8, n = 4): Cr 62 °C NcybC 96 °C Iso [51]. The transition temperatures were obtained on
Optical orientation of nematic liquid crystal droplets via photoisomerization of an azodendrimer dopant
Beilstein J. Nanotechnol. 2018, 9, 870–879, doi:10.3762/bjnano.9.81
- , Taiwan 10.3762/bjnano.9.81 Abstract Two sequential transformations of the orientational structure in nematic liquid crystal droplets containing a dendrimer additive (nanosized macromolecules with light-absorbing azobenzene terminal moieties) under light irradiation in the UV–blue spectral range were
- investigated. The origin of these transitions is in the change of the boundary conditions due to photoisomerization of the dendrimer adsorbed onto the liquid crystal–glycerol interface. It was shown that the photoisomerization processes of dendrimer molecules in a liquid crystal are accompanied by a spatial
- rearrangement of their azobenzene moieties, which is the key point in the explanation of the observed effects. Keywords: dendrimer; droplets; nematic liquid crystal; orientational transition; photo-orientation; Introduction Azobenzene compounds represent a very convenient tool for the development of
Effect of ferroelectric BaTiO3 particles on the threshold voltage of a smectic A liquid crystal
Beilstein J. Nanotechnol. 2018, 9, 824–828, doi:10.3762/bjnano.9.76
- electric field [10]. The Fréedericksz transition occurs at least in two stages when the BaTiO3 nanoparticles are added to the liquid crystal [11][12]. In colloids of ferroelectric particles in nematic LCs, as a rule, oleic acid is present as a stabilizer, the role of which is to prevent the aggregation of
- ferroelectric particles. The oleic acid in many cases worsens the materials properties, for example, reduces the clearing point of the liquid crystal [13]. Thanks to the layered structure, smectic LCs have special physical (mechanical, electrical and optical) properties, which opens up wide possibilities for
- dielectric constant of the colloid consisting of liquid crystal and ferroelectric particles can be represented in the form Here, f is the volume fraction of ferroelectric particles, εLC(E) and εFP(E) are the permittivity values of LC and ferroelectric particles both depending on the electric field strength E
Engineering of oriented carbon nanotubes in composite materials
Beilstein J. Nanotechnol. 2018, 9, 415–435, doi:10.3762/bjnano.9.41
- cover a wide area of the substrate [95]. Liquid crystal molecules When a solid is heated to its melting point it loses its molecular order and is converted to a liquid with molecules in random orientation. When heated, some materials such as cholesteryl benzoate first convert to a liquid crystal (LC
- molecular structure of the liquid crystal (LC) (i.e., that it can be simply oriented in the direction of an applied electric or magnetic field) the alignment and dispersion of the CNTs in a solution of liquid crystals is also achievable (Figure 15). The biggest advantage of this method is that small fields
- solution and a nozzle to control the N2 flow direction on the Si substrate. SEM image of aligned CNTs is reproduced with permission from [95], copyright 2005 American Institute of Physics. Schematic structure of a liquid crystal (blue ellipsoids) and CNT (black cylinders) rearrangement under an external
Dynamic behavior of nematic liquid crystal mixtures with quantum dots in electric fields
Beilstein J. Nanotechnol. 2018, 9, 399–406, doi:10.3762/bjnano.9.39
- on a sample containing 0.89% (mass fraction) of CdSe/ZnS quantum dots revealed a decrease of the relaxation time compared to pure 5CB. Keywords: Fréedericksz transition; nematic liquid crystals; quantum dots; Introduction The expansion of liquid crystal (LC)-based devices in common life domains as
- quantum dot surface. Dynamic experiments performed in alternating electric fields proved that by adding a small amount of CdSe/ZnS quantum dots in thermotropic nematic liquid crystal with positive dielectric anisotropy, we obtain a decrease of the relaxation time. When an external electric field higher
- than the Fréedericksz transition threshold [18][19] is applied transversely to a planar liquid crystal cell, the molecules change their orientation tending to align their director in parallel to the field. This reorientation is illustrated by an intensity variation of a laser beam crossing through the
Temperature-tunable lasing from dye-doped chiral microdroplets encapsulated in a thin polymeric film
Beilstein J. Nanotechnol. 2018, 9, 379–383, doi:10.3762/bjnano.9.37
- 87036, Italy 10.3762/bjnano.9.37 Abstract In the last decade, much interest has grown around the possibility to use liquid-crystal droplets as optical microcavities and lasers. In particular, 3D laser emission from dye-doped cholesteric liquid crystals confined inside microdroplets paves the way for
- many applications in the field of sensors or tunable photonics. Several techniques can be used to obtain small microresonators as, for example, dispersing a liquid crystal inside an immiscible isotropic fluid to create an emulsion. Recently, the possibility to obtain a thin free-standing film starting
- − no is the birefringence of the liquid crystal. The PBG spectral position is sensitive to external or internal factors as electric and electromagnetic fields, temperature and local order variations [1][2][3][4]. Due to the presence of a PBG, CLCs behave as Bragg resonators that can be used to build up
Periodic structures on liquid-phase smectic A, nematic and isotropic free surfaces
Beilstein J. Nanotechnol. 2018, 9, 342–352, doi:10.3762/bjnano.9.34
- isotropic liquid shows the independence of the stripe nature on the liquid crystal phase properties. The stripes disappear with increasing temperature due to the disappearance of the elastic constants on the surface. The striped formation is not a surface ordering effect like in [2][16]. On the surface
- ordering [2][21][22][23][24], the surface remains smooth and we observe only director orientation variation. Conclusion A complex study of the liquid crystal 8CB free surface in the smectic A phase was carried out. The structures of the free surface are studied using four techniques: Polarized microscopy
- amplitudes by the program MetroPro. A piece of LC display was used as a substrate (Figure 12), which provides two main advantages. First, it has a large anchoring energy for theliquid crystal director field, and second, helps to better focus at the bottom edge of the liquid crystal layer. During the
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