Photoconductivity of Discotic Liquid Crystals Derived from A Long-Chain Tetraphenylporphyrin

1999 ◽  
Vol 559 ◽  
Author(s):  
Y. Shimizu ◽  
H. Monobe ◽  
S. Mima ◽  
T. Higashiyama ◽  
T. Fuchita ◽  
...  
Keyword(s):  
Hole Mobility ◽  
Discotic Liquid Crystals ◽  
Molecular Motions ◽  
Phase Transition Behavior ◽  
Electronic Process ◽  
Arrhenius Dependence ◽  
Glass Slides ◽  
Ito Glass ◽  
Sandwich Type ◽  
Long Chain

ABSTRACTPhotoconductivity of a mesogenic tetraphenylporphyrin (TPP) is shown in relation to the mesomorphic phase transition behavior. The TPP mesogen shows two types of mesophases having smectic-like order (lamellar mesophases : DL and DLC phases named in this work) and the photocurrent changes stepwise at the phase transitions with non-Arrhenius dependence whilst the darkcurrent tends to be Arrhenius. The hole mobility was measured for the random domain cell and was found to be faster than 10−4 cm2v−1sec−1 in the mesophases. The cell used for the photocurrent measurements was a sandwich-type one using two ITO glass slides as electrtodes and show rectification behavior for the crystal and the low-temperature mesophase (DLC) in contrast to non-rectification of photocurrent in the high-temperature mesophase (DL). These properties of charge carrier migration as an electronic process are profoundly related to molecular order as well as molecular motions in mesophase.

Discotic Liquid Crystals of Transition metal Complexes 23: Synthesis and Mesomorphism of Tetrakis(3,4-di-n-alkylphenyl)porphyrin Derivatives and Their Metal Complexes

1999 ◽  
Vol 03 (04) ◽  
pp. 249-258 ◽  
Author(s):  
KAZUCHIKA OHTA ◽  
MASAHIRO ANDO ◽  
IWAO YAMAMOTO
Keyword(s):  
Liquid Crystal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Room Temperature ◽  
Discotic Liquid Crystals ◽  
X Ray ◽  
Alkyl Chains ◽  
Porphyrin Derivatives ◽  
Crystal Phases ◽  
Long Chain

Five novel long-chain-substituted porphyrin derivatives, tetrakis(3,4-dialkylphenyl)porphyrins (abbreviated as (Cn)8 TPPH 2 (n = 8, 12, 18), ( C 18)8 TPPCu and ( C 18)8 TPPNi ), were synthesized and their mesomorphism was investigated. It was found that the (Cn)8 TPPH 2 (n = 8, 12), derivatives are isotropic liquids at room temperature and that each of the ( C 18)8 TPPM ( M ≡ H 2, Cu , Ni ) derivatives has two liquid crystal phases M1 and M2 and two unidentified phases X1 and X2. It was revealed by X-ray studies that the M2 phase is a discotic lamellar (DL) phase. Interestingly, these porphyrin derivatives exhibit not a columnar but a lamellar mesophase, even though they have a disk-like central core with eight alkyl chains in the surroundings.

Discotic liquid crystals of transition metal complexes 42: the detailed phase structures and phase transition mechanisms of two Cub mesophases shown by discotic liquid crystals based on phthalocyanine metal complexes

2010 ◽  
Vol 14 (02) ◽  
pp. 188-197 ◽  
Author(s):  
Hidetomo Mukai ◽  
Miho Yokokawa ◽  
Masahiro Ichihara ◽  
Kazuaki Hatsusaka ◽  
Kazuchika Ohta
Keyword(s):  
Phase Transition ◽  
Liquid Crystals ◽  
Metal Complexes ◽  
Discotic Liquid Crystals ◽  
Temperature Dependent ◽  
Transition Mechanism ◽  
Short Columns ◽  
Phase Structures ◽  
Sandwich Type ◽  
Columnar Mesophases

We found in our previous works that the sandwich-type phthalocyanine-based rare earth metal complexes, bis[2,3,9,10,16,17,23,24-octakis(3,4-dialkoxyphenoxy)phthalocyaninato]lanthanoid(III) ({[( C n O )2 PhO ]8 Pc }2 M, M = Eu and Lu , n = 8–16) (1 and 3), exhibited two thermotropic cubic mesophases, Cub1 and Cub2, together with columnar mesophases. It is rare that the discotic liquid crystalline compounds show the cubic mesophase. We revealed that their symmetries of the lower temperature Cub1 mesophase and the higher temperature Cub2 mesophase were [Formula: see text] and [Formula: see text], respectively. However, their detailed phase structures were not revealed in the previous works. In this work, we have synthesized a series of novel sandwich-type phthalocyanine-based terbium complexes, bis[2,3,9,10,16,17,23,24-octakis(3,4-dialkoxyphenoxy)phthalocyaninato]terbium(III) ({[( C n O )2 PhO ]8 Pc }2 Tb , n = 8–16) (2). Their mesomorphic properties have been investigated using polarization microscope, DSC and temperature-dependent X-ray diffraction techniques. As the result, the present Tb complexes (2) also showed two cubic mesophases, [Formula: see text] and [Formula: see text], together with columnar mesophases, as well as the previous Eu homologs (1) and Lu homologs (3). We have furthermore investigated by using temperature-dependent electronic absorption spectroscopy to reveal their detailed phase structures and phase transition mechanism of these two Cub mesophases. We have revealed that the [Formula: see text] mesophase forms a bicontinuous structure consisting of branched columns like jungle gym, but that the [Formula: see text] mesophase forms a discontinuous structure consisting of short columns like drums that resulted from the cutting off of the branched columns.

A FED PROTOTYPE USING PATTERNED DLC THIN FILMS AS THE CATHODE

2002 ◽  
Vol 16 (06n07) ◽  
pp. 993-997 ◽  
Author(s):  
W. LI ◽  
T. FENG ◽  
D. S. MAO ◽  
X. WANG ◽  
X. H. LIU ◽  
...  
Keyword(s):  
Thin Films ◽  
Electrophoretic Deposition ◽  
Ion Beam ◽  
Broad Band ◽  
Ion Beam Etching ◽  
Glass Slides ◽  
Bluish Green ◽  
Ito Glass ◽  
Titanium Thin Films ◽  
Arc Deposition

In our study, diamond-like-carbon (DLC) thin films were prepared by filtered arc deposition (FAD), which provided a way to deposit DLC thin films on large areas at room temperature. Glass slides coated 100nm chromium or titanium thin films were used as cathode substrates. Millions of rectangular holes with sizes of 5 × 5μm were made on the DLC films using a routine patterning process. Here a special reactive ion beam etching method was applied to etch the DLC films. The anodes of the devices were made by electrophoretic deposition. ZnO:Zn phosphor (P15) was employed, which has a broad band bluish green (centered at 490nm). Before electrophoretic deposition, the anode substrates (ITO glass slides) had been patterned into 50 anode electrodes. In order to improve the adherence of phosphor layers, the as-deposited screens were treated in Na2SiO3 solution for 24h to add additional binder. A kind of matrix-addressed diode FED prototype was designed and packaged. 50-100μm-thick glass slides were used as spacers and getters were applied to maintain the vacuum after the exhaustion. The applied DC voltage was ranged in 0-3000V and much higher current density was measured in the cathode-patterned prototypes than the unpatterned ones during the test. As a result, characters could be well displayed.

Temperature-independent hole mobility in discotic liquid crystals

2001 ◽  
Vol 114 (4) ◽  
pp. 1797-1802 ◽  
Author(s):  
T. Kreouzis ◽  
K. J. Donovan ◽  
N. Boden ◽  
R. J. Bushby ◽  
O. R. Lozman ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Hole Mobility ◽  
Discotic Liquid Crystals

Metal-Modulated Growth of Au Nanoparticles by Electropolymerized 8-Hydroxyquinoline Films

2012 ◽  
Vol 503-504 ◽  
pp. 334-337
Author(s):  
Hong Cheng Pan ◽  
Wei Hong Liu ◽  
Xue Peng Li ◽  
Yan Bin Ren ◽  
Shan Hu Liu
Keyword(s):  
Indium Tin Oxide ◽  
Au Nanoparticles ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Au Nanoparticle ◽  
Buffer Solution ◽  
Ito Electrode ◽  
Glass Slides ◽  
Ito Glass ◽  
Pulse Voltammetry

8-hydroxyquinoline (8-Hq) films were electropolymerized on indium-tin-oxide-coated (ITO) glass slides by using cyclic voltammetry. The 8-Hq electropolymerized on ITO electrode (8-Hq/ITO) was immersed in a 5-mL solution containing 0.01 M phosphate buffer solution (PBS, pH 7.0), 0.8 mM cetyltrimethylammonium chloride, 20 µL of HAuCl4 (1%, w/w), and 50 µL of Au nanoparticle seeds. The mixture was incubated at 57oC for 3 h. Then Au nanoparticles were grown and deposited onto the 8-Hq/ITO electrode. It was found that some metal ions (Zn2+, Cd2+, Mg2+, and Pb2+) could inhibit the growth of Au nanoparticles. The metal-modulated growth of Au nanoparticles was studied by UV-vis spectra and differential pulse voltammetry.

scholarly journals Low-Cost Electrodeposition of Size-Tunable Single-Crystal ZnO Nanorods

Fibers ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 38
Author(s):  
Elias Sakellis ◽  
Antonis Markopoulos ◽  
Christos Tzouvelekis ◽  
Manolis Chatzigeorgiou ◽  
Anastasios Travlos ◽  
...  
Keyword(s):  
Single Crystal ◽  
Seed Layer ◽  
Physical Vapor Deposition ◽  
Growth Parameters ◽  
Low Cost ◽  
Zno Nanorods ◽  
Large Area ◽  
Glass Slides ◽  
Ito Glass ◽  
Effect Of Oxygen

In this paper we report a low cost, simple, electrochemical method for large-area growth of single crystal ZnO nanorods. The method utilizes a metallic zinc foil as the source of the necessary zinc ions for ZnO growth on indium-doped tin oxide (ITO) glass slides. The method is thoroughly discussed and investigated varying all the parameters involved. The resulting ZnO nanorods are highly oriented along c-axis and densely packed, while their length and diameter can be tuned by varying the growth parameters. Two different types of seed layers on the ITO glass slides are tested. A seed layer made by spin coating of ZnO nanoparticles results in a twofold increase of the ZnO nanorod surface density as compared with a ZnO thin film seed layer by physical vapor deposition. Additionally, the effect of oxygen supply during electrodeposition was investigated as a crucial regulatory parameter not only for the geometrical and topological characteristics of the ZnO nano-arrays but for their physical properties as well.

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