TY - JOUR
AB - The alignment of liquid crystals on surfaces plays a central role in optimizing their performances. In this work, a cutting-edge nano-lithography-based method to control the local orientation of a thermotropic liquid crystal is applied to easily available commercial standard materials and evaluated. Parallel nanogrooves on a substrate, created through 3D nanoprinting in a negative-tone photoresin optimized for two-photon polymerization are used for this purpose. Azimuthal anchoring energies of the order from 10−6 J/m2 to 10−5 J/m2 are found, depending on the spacing, width and depth of the grooves. In part, these values are larger than those reported previously for another photopolymer. Both uniform alignment and spatial patterns of different alignment directions can be realized. Electro-optic studies confirm the suitability of the method for electrically addressable photonic applications and indicate strong polar anchoring.
AU - Zhang, Bingru
AU - Plidschun, Malte
AU - Schmidt, Markus A.
AU - Kitzerow, Heinz-Siegfried
ID - 49609
IS - 12
JF - Optical Materials Express
KW - Electronic
KW - Optical and Magnetic Materials
SN - 2159-3930
TI - Anchoring and electro-optic switching of liquid crystals on nano-structured surfaces fabricated by two-photon based nano-printing
VL - 13
ER -
TY - JOUR
AB - Geometric-phase dielectric meta-lenses made of silicon with high numerical aperture and short focal lengths are fabricated and characterised. For circularly polarised light, the same meta-lens can act as a converging or diverging lens, depending on the handedness of the circular polarisation. This effect enables application for optical tweezers that trap or release µm-size polymer beads floating in a microfluidic channel on demand. An electrically addressable polarisation converter based on liquid crystals may be used to switch between the two states of polarisation, at which the light transmitted through the meta-lens is focused (trapping) or defocussed (releasing), respectively.
AU - Geromel, René
AU - Rennerich, Roman
AU - Zentgraf, Thomas
AU - Kitzerow, Heinz-Siegfried
ID - 40513
IS - 7-10
JF - Liquid Crystals
TI - Geometric-phase metalens to be used for tunable optical tweezers in microfluidics
VL - 50
ER -
TY - JOUR
AU - Zhang, Bingru
AU - Nguyen, Linh
AU - Martens, Kevin
AU - Heuer-Jungemann, Amelie
AU - Philipp, Julian
AU - Kempter, Susanne
AU - Rädler, Joachim O.
AU - Liedl, Tim
AU - Kitzerow, Heinz-Siegfried
ID - 43440
IS - 7-10
JF - Liquid Crystals
KW - Condensed Matter Physics
KW - General Materials Science
KW - General Chemistry
SN - 0267-8292
TI - Luminescent DNA-origami nano-rods dispersed in a lyotropic chromonic liquid crystal
VL - 50
ER -
TY - JOUR
AB - AbstractA detailed investigation of the energy levels of perylene-3,4,9,10-tetracarboxylic tetraethylester as a representative compound for the whole family of perylene esters was performed. It was revealed via electrochemical measurements that one oxidation and two reductions take place. The bandgaps determined via the electrochemical approach are in good agreement with the optical bandgap obtained from the absorption spectra via a Tauc plot. In addition, absorption spectra in dependence of the electrochemical potential were the basis for extensive quantum-chemical calculations of the neutral, monoanionic, and dianionic molecules. For this purpose, calculations based on density functional theory were compared with post-Hartree–Fock methods and the CAM-B3LYP functional proved to be the most reliable choice for the calculation of absorption spectra. Furthermore, spectral features found experimentally could be reproduced with vibronic calculations and allowed to understand their origins. In particular, the two lowest energy absorption bands of the anion are not caused by absorption of two distinct electronic states, which might have been expected from vertical excitation calculations, but both states exhibit a strong vibronic progression resulting in contributions to both bands.
AU - Wiebeler, Christian
AU - Vollbrecht, Joachim
AU - Neuba, Adam
AU - Kitzerow, Heinz-Siegfried
AU - Schumacher, Stefan
ID - 39653
IS - 1
JF - Scientific Reports
KW - Multidisciplinary
SN - 2045-2322
TI - Unraveling the electrochemical and spectroscopic properties of neutral and negatively charged perylene tetraethylesters
VL - 11
ER -
TY - JOUR
AU - Atorf, Bernhard
AU - Mühlenbernd, Holger
AU - Zentgraf, Thomas
AU - Kitzerow, Heinz-Siegfried
ID - 16301
IS - 6
JF - Optics Express
SN - 1094-4087
TI - All-optical switching of a dye-doped liquid crystal plasmonic metasurface
VL - 28
ER -
TY - JOUR
AU - Keum, Changmin
AU - Becker, David
AU - Archer, Emily
AU - Bock, Harald
AU - Kitzerow, Heinz-Siegfried
AU - Gather, Malte C.
AU - Murawski, Caroline
ID - 35869
IS - 17
JF - Advanced Optical Materials
KW - Atomic and Molecular Physics
KW - and Optics
KW - Electronic
KW - Optical and Magnetic Materials
SN - 2195-1071
TI - Organic Light‐Emitting Diodes Based on a Columnar Liquid‐Crystalline Perylene Emitter
VL - 8
ER -
TY - JOUR
AU - Risse, Anna Margareta
AU - Schmidtke, Jürgen
AU - Kitzerow, Heinz-Siegfried
ID - 35859
IS - 7
JF - Liquid Crystals
KW - Condensed Matter Physics
KW - General Materials Science
KW - General Chemistry
SN - 0267-8292
TI - Dynamics of a liquid crystal-based modulator with germanium substrates for mid-infrared radiation
VL - 48
ER -
TY - JOUR
AB - Rod-like and sheet-like nano-particles made of desoxyribonucleic acid (DNA) fabricated by the DNA origami method (base sequence-controlled self-organized folding of DNA) are dispersed in a lyotropic chromonic liquid crystal made of an aqueous solution of disodium cromoglycate. The respective liquid crystalline nanodispersions are doped with a dichroic fluorescent dye and their orientational order parameter is studied by means of polarized fluorescence spectroscopy. The presence of the nano-particles is found to slightly reduce the orientational order parameter of the nematic mesophase. Nano-rods with a large length/width ratio tend to preserve the orientational order, while more compact stiff nano-rods and especially nano-sheets reduce the order parameter to a larger extent. In spite of the difference between the sizes of the DNA nano-particles and the rod-like columnar aggregates forming the liquid crystal, a similarity between the shapes of the former and the latter seems to be better compatible with the orientational order of the liquid crystal.
AU - Zhang, Bingru
AU - Martens, Kevin
AU - Kneer, Luisa
AU - Funck, Timon
AU - Nguyen, Linh
AU - Berger, Ricarda
AU - Dass, Mihir
AU - Kempter, Susanne
AU - Schmidtke, Jürgen
AU - Liedl, Tim
AU - Kitzerow, Heinz-Siegfried
ID - 35868
IS - 9
JF - Nanomaterials
KW - General Materials Science
KW - General Chemical Engineering
SN - 2079-4991
TI - DNA Origami Nano-Sheets and Nano-Rods Alter the Orientational Order in a Lyotropic Chromonic Liquid Crystal
VL - 10
ER -
TY - JOUR
AU - Atorf, Bernhard
AU - Auf der Landwehr, Chris Holm
AU - Rennerich, Roman
AU - Kitzerow, Heinz-Siegfried
ID - 13870
JF - The Journal of Physical Chemistry B
SN - 1520-6106
TI - Midinfrared Birefringence of Liquid Crystals, Polarimetry, and Intensity Modulators
ER -
TY - JOUR
AU - Zhang, Bingru
AU - Schmidtke, Jürgen
AU - Kitzerow, Heinz-Siegfried
ID - 35872
IS - 8
JF - Advanced Optical Materials
KW - Atomic and Molecular Physics
KW - and Optics
KW - Electronic
KW - Optical and Magnetic Materials
SN - 2195-1071
TI - Fabrication of Lyotropic Alignment Layers for Thermotropic Liquid Crystals Facilitated by a Polymer Template
VL - 7
ER -
TY - CONF
AU - Temme, Julian
AU - Meyers, Thorsten
AU - Reker, Julia
AU - Vidor, Fábio F.
AU - Vollbrecht, Joachim
AU - Kitzerow, Heinz-Siegfried
AU - Paradies, Jan
AU - Hilleringmann, Ulrich
ED - du Plessis, Monuko
ID - 35870
T2 - Fifth Conference on Sensors, MEMS, and Electro-Optic Systems
TI - Improved organic thin-film transistor performance by dielectric layer patterning
ER -
TY - JOUR
AU - Kitzerow, Heinz-Siegfried
ID - 39971
IS - 1
JF - Liquid Crystals Today
KW - Materials Chemistry
KW - Inorganic Chemistry
KW - Condensed Matter Physics
SN - 1358-314X
TI - Pawel Pieranski – crystallographer of liquids and Alfred-Saupe-prize laureate 2019
VL - 28
ER -
TY - JOUR
AU - Vollbrecht, Joachim
AU - Wiebeler, Christian
AU - Bock, Harald
AU - Schumacher, Stefan
AU - Kitzerow, Heinz-Siegfried
ID - 13343
IS - 7
JF - The Journal of Physical Chemistry C
SN - 1932-7447
TI - Curved Polar Dibenzocoronene Esters and Imides versus Their Planar Centrosymmetric Homologs: Photophysical and Optoelectronic Analysis
VL - 123
ER -
TY - JOUR
AU - Atorf, Bernhard
AU - Friesen, Simon
AU - Rennerich, Roman
AU - Mühlenbernd, Holger
AU - Zentgraf, Thomas
AU - Kitzerow, Heinz-Siegfried
ID - 8798
JF - Polymer Science, Series C
SN - 1811-2382
TI - Switchable Plasmonic Metasurface Utilizing the Electro-Optic Kerr Effect of a Blue Phase Liquid Crystal
VL - 60
ER -
TY - JOUR
AU - Atorf, Bernhard
AU - Rasouli, Hoda
AU - Mühlenbernd, Holger
AU - Reineke, Bernhard J.
AU - Zentgraf, Thomas
AU - Kitzerow, Heinz-Siegfried
ID - 1764
IS - 8
JF - The Journal of Physical Chemistry C
SN - 1932-7447
TI - Switchable Plasmonic Holograms Utilizing the Electro-Optic Effect of a Liquid-Crystal Circular Polarizer
VL - 122
ER -
TY - JOUR
AU - Atorf, Bernhard
AU - Friesen, Simon
AU - Rennerich, Roman
AU - Mühlenbernd, Holger
AU - Zentgraf, Thomas
AU - Kitzerow, Heinz-Siegfried
ID - 13871
JF - Polymer Science, Series C
SN - 1811-2382
TI - Switchable Plasmonic Metasurface Utilizing the Electro-Optic Kerr Effect of a Blue Phase Liquid Crystal
ER -
TY - JOUR
AU - Vollbrecht, Joachim
AU - Oechsle, Peter
AU - Stepen, Arne
AU - Hoffmann, Florian
AU - Paradies, Jan
AU - Meyers, Thorsten
AU - Hilleringmann, Ulrich
AU - Schmidtke, Jürgen
AU - Kitzerow, Heinz-Siegfried
ID - 22244
JF - Organic Electronics
SN - 1566-1199
TI - Liquid crystalline dithienothiophene derivatives for organic electronics
ER -
TY - JOUR
AU - Vollbrecht, Joachim
AU - Stepen, Arne
AU - Nolkemper, Karlo
AU - Keuker-Baumann, Susanne
AU - Kitzerow, Heinz-Siegfried
ID - 39659
IS - 1
JF - Polymer Science, Series C
KW - Materials Chemistry
KW - Polymers and Plastics
KW - General Chemistry
SN - 1811-2382
TI - Blends of Two Perylene Derivatives: Mesogenic Properties and Application As Emitter Materials in OLEDs
VL - 60
ER -
TY - JOUR
AB - Switchable two dimensional liquid crystal diffraction gratings are promising can-
didates in beam steering devices, multiplexers and holographic displays. For these areas of applications a high degree of integration in optical systems is much sought-after. In the context of diffraction gratings this means that the angle of diffraction should be rather high, which typically poses a problem as the fabrication of small grating periods is challenging. In this paper, we propose the use of nanosphere lithography (NSL) for the fabrication of two-dimensionally
structured electrodes with a periodicity of a few micrometers. NSL is based on the self-assembly of micro- or nanometer sized spheres into monolayers. It allows for easy substrate structuring on wafer scale. The manufactured electrode is combined with a liquid crystalline polymer-stabilized blue phase, which facilitates sub-millisecond electrical switching of the diffraction efficiency at adiffractionangle of 21.4°.
AU - Wahle, M.
AU - Brassat, Katharina
AU - Ebel, J.
AU - Bürger, Julius
AU - Lindner, Jörg
AU - Kitzerow, Heinz-Siegfried
ID - 3997
IS - 19
JF - Optics Express 25
TI - Two-dimensional switchable blue phase gratings manufactured by nanosphere lithography
VL - 25
ER -
TY - JOUR
AU - Vollbrecht, Joachim
AU - Wiebeler, Christian
AU - Schumacher, Stefan
AU - Bock, Harald
AU - Kitzerow, Heinz-Siegfried
ID - 13358
JF - Molecular Crystals and Liquid Crystals
SN - 1542-1406
TI - Enhanced columnar mesophase range through distortions in arene cores
ER -