Reflection image enhancement for photonic crystal devices by using dielectrics

Abstract

We investigated the optical properties of photonic crystal devices (PCDs) using dielectrics. Different dielectrics were injected into a cell gap of the PCDs as a swelling solvent. It is evident that the PCDs reflected a deep blue color when two different materials, chiral ionic liquid (CIL) and photosensitive small molecules, were introduced. To compare the reflection images according to the different dielectrics, a well-known ionic liquid (IL) was used as a control sample. A thinner polymer layer induced a shorter wavelength, which created a strong blue shift phenomenon with a larger refraction index and a larger dielectric constant. In this paper, we obtained 12?nm of reflection enhancement with an applied voltage of 2V using an IL and a deep-blue color image by using the effects of the molecular structure of the CIL and photosensitive materials.     

X-ray structural and molecular mechanics investigation of cyclopentadienyl-carbonyl-triphenylophosphine-phenylacetyliron, (η5-C5H5)Fe(CO)(PPh3)(COCH2C6H5)

The crystal and molecular structure of cyclopentadienyl-carbonyl-triphenylphosphine-phenylacetyl-iron (1) has been determined on the basis of X-ray data. The crystals are triclinic, space groupP¯1 (Z=2) with cell dimensions:a=9.546(1),b=10.233(1),c=5.012(2) Å,=93.70(1),=101.12(1), =112.58(1)°. The structure was solved by direct methods and refined anisotropically by a full-matrix, least-squares procedure against 4964 independent reflections, givingR=0.0416. The MM calculations done for a model of1 reproduced satisfactorily the X-ray structure.On leave from the Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China.     

Growth of high quality anthracene crystals by a simple solution technique

In recent years considerable effort has gone into the preparation and characterisation of high purity anthracene crystals, since anthracene is used as a model organic molecular crystal in studies of solid‐state properties. Studies of organic molecular crystals and their applications in optics and electronics have been increasing attractive interest. Several attempts have been made to grow single crystals of anthracene. This is the first attempt to grow high quality anthracene crystals by solution technique adopting slow evaporation method in different solvents like CS₂ and CCl₄. The harvested crystals were subjected to various characterization studies. The results of characterisation studies support the purity of solution grown anthracene crystals. The solubility of anthracene in various solvents like CS₂ and CCI₄ was determined. The crystals of anthracene were grown by systematic method of slow evaporation technique in various solvents. Different morphology is noted with varying solvents. The crystal was subjected to XRD studies, FTIR studies and thermal studies. © 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim     

Synthesis and Characterization of Violet Light Emitting Polymer based on Fluorene and Dimethylsilane

New fluorene based light emitting polymer, poly[(4-(9,9-didecyl-9H-fluoren-2-yl) phenyl)dimethyl(phenyl)silane] (PFDPS), was synthesized by palladium-catalzed Suzuki coupling reaction. The obtained copolymer was characterized by ¹H-NMR, and IR-spectroscopy. The polymer showed good solubility in common organic solvents and weight average molecular weight of 16,300 with polydispersity index of 1.4. The maximum photoluminescence of the solution and film of the polymer was observed at 392 nm and 410 nm, respectively.

The double-layered device with the configuration, ITO/PEDOT/PFDPS/LiF/Al structure has a turn-on voltage at about 5.5 V and maximum brightness of 9.40 cd/m², and emitted violet light at 414 nm.     

X-ray structural investigation of N-epimeric 1,8-cis- and 1,8-trans-5,12-dimethyl-1,4,8,11-tetraazacyclotetradeca-4,11-dienenickel(II) diperchlorates,C12H24N4Ni(ClO4)2

The structures of 1,8-cis- and 1,8-trans-5, 12-dimethyl-1,4,8,11-tetra-azacyclotetradeca-4,11-dienenickel(II) diperchlorates (I andII, respectively) have been investigated by X-ray diffracto-metric methods. CompoundI crystallizes in a monoclinic system, space group P2₁/n, with cell dimensionsa=13.732(2),b=13.526(2),c=10.658(2) Å,=99.20(2)°; compoundII crystallizes in a monoclinic system, space group C2/c, with cell dimensionsa=15.776(2),b=9.919(1),c=12.451(1) Å,=102.27(1)°. The structures were solved by heavy atommethods and refined by a full-matrix least-squares method to giveR=0.0601 and 0.0575 forIandII, respectively. Both N-epimers show the square planar Ni(II) coordination arrangements. The ligand ofI has approximate twofold symmetry (C₂ perpendicular to the coordination plane), the moleculeII is crystallographically centrosymmetric (C_i).     

Dielektrische Eigenschaften und Phasenübergänge von M2SbF5 -Kristallen

This paper presents the results of investigations of complex dielectric constants ϵ* = ϵ′ — ιϵ″ at audio and mikrowave frequencies and d.c. conductivity versus temperature in M₂SbF₅-type ionic single crystals. The anomalies in these properties were observed along the b-axis which are expected to be related to structural phase transitions. An electric field causes the switching effect and negative-resistance I–E curves. In contrast to other antimony compounds the phonon contribution to ϵ(0) is small. However, it is considered that the audio-frequency anomalies of ϵ* are increased by the coupling of order parameter phonon with disorder modes.     

Crystal and molecular structure of 2,6-dihydroxybenzoic acid

The crystal and molecular structure of 2,6-dihydroxybenzoic acid has been determined by single crystal X-ray diffraction. The crystals are monoclinic witha=5.4084(5),b=5.2240(7),c=22.986(4) Å, =94.69(3)°, space group P2₁/c,Z=4,V=647.27(16) ų,d _c =1.58Mg m^–3, The acid crystallizes as hydrogen bonded carboxylic dimers which pack to generate a herringbone motif of the type typically encountered in polycyclic aromatic compounds.     

X-ray structures of two methoxybenzo[b]thiophenes

The crystal and molecular structures of two methoxybenzo[b]thiophenes have been determined by three-dimensional, single-crystal X-ray diffractometry. Both 3-(4-hydroxy-3, 5-dimethoxybenzoyl)-2-(4-methoxyphenyl)-6-methoxybenzo[b]thiophene and 3-(2,6-dimethoxybenzoyl)-2-(4-methoxyphenyl)-6-methoxybenzo[b]thiophene (hereafter referred to asI andII, respectively) crystallize in the monoclinic centrosymmetric space groupP2₁/n (No. 14, C _2h ⁵ ) with four formula units-per cell witha=6.866(1),b=28.638(2),c=11.830(2) Å, and =105.52(1)° anda=9.328(1),b=7.977(1),c=29.650(4) Å, and =97.87(1)°, respectively. The phase problems were solved by direct methods and the respective final full-matrix least-squares refinements converged toR=0.046 and 0.031. The structures differ in the positioning of the dimethoxy groups of the benzoyl ligands and the addition of a hydroxyl group inI. The molecules in the crystal lattice are held together by van der Waals forces plus the addition of hydrogen bonding in compoundI. Selected bond distances and angles and torsion angles are tabularized.     

Structure and IR,UV spectroscopic behavior of azabicyclo[2.2.2]octane pentachlorophenolate

The structure of C₆Cl₅O^–·C₇H₁₃NH⁺ has been determined by X-ray diffraction. The crystals are orthorhombic:Pcab,a=10.706(1),b=11.966(2),c=24.913(5)Å,Z=8. The structure was solved by direct methods, and refined to R=0.042 for 1523 nonzero reflections. The N⁺-HO^– hydrogen bond is shortened (2.553(5)Å) and deformed (相似文献   

The Effective Temperature of Surfaces of Liquid Metals and Some Non-Metals

An estimation of decrease of atomic bond energy by raising temperature for surfaces of liquid metals and some non-metals had been made. The calculation values of the derivative du_sdu_b where u_s and u_b, are bond energy of atoms in surface and bulk of a liquid, are significantly above 1 and in limits from 2 to 10. It was supposed that this results from anomalously intensive thermal expansion of surface layers of liquids – the effect which is well known for crystal surfaces. This expansion was explained by the effective temperature of these surfaces which, thus, was found to be by several times above those for bulk of liquids.     

Measurement of the An isotropic Refractive Indices of Polybenzylglutamate Liquid Crystals. Molecular Factors and Dispersion

The ordinary and extraordinary refractive indices have been measured for lyotropic liquid crystal solutions of poly-γ-benzyl-L-glutamate. The onset of the liquid crystal formation is noted as an abrupt jump in the sample birefringence in the biphasic region. The concentration dependence is otherwise unremarkable. The polymer is found to add a small, anisotropic increment to the refractivity of the supporting solvent. Both n _o and n _e can thus be measured in an ordinary Abbé refractometer for the low refractive solvents common to these liquid crystal solutions. The optical birefringence does not depend significantly on polymer molecular weight. Data is also included for the wavelength dependence (dispersion) of n _o, n _e, and Δn.     

Crystallographic investigation of single crystals of the mesogen compound 4′-nitrophenyl-4-n-octyloxybenzoate

X-ray investigations of single crystals of 4′-nitrophenyl-4-n-octyloxybenzoate (NPOB) have been performed for the determination of the space group P2₁/c and the lattice constants (a₀ = 16.77 ± 0.02 Å, b₀ = 9.207 ± 0.005 Å, c₀ = 16.72 ± 0.01 Å, β = 128.0 ± 0.5°). Furthermore powder patterns after Debye-Scherrer method have been taken to estimate the d-values together with the indexing. On the basis of small Miller indices the crystal angles yielded a discrepancy between axis ratios determined from optical measurements and X-ray methods. It can be shown that these differences appear with many molecular crystals.     

Crystal and molecular structure ofdl-lysine hydrochloride

The crystal structure ofdl-lysine hydrochloride has been determined by the heavy-atom technique, using three-dimensional X-ray photographic data. The crystals are monoclinic with space groupP2₁/c, a = 9.26(2),b = 11.36(2),c = 8.66(2) Å and = 105.4(4) °. The structure was refined by the full-matrix least-squares methods to a finalR value of 0.10. The torsion angles defining the side-chain conformation ofdl-lysine hydrochloride are significantly different from those ofl-lysine hydrochloride.     

Processing optimization and optical properties of 3-D photonic crystals

The synthesis optimization of three-dimensional photonic crystals (direct and inverse opals) is discussed in terms of the influence of processing parameters on the final optical quality. A colloidal/sol–gel route, starting with the self-organization of polystyrene microspheres into opal structures by convective self-assembly, followed by infiltration with a dielectric matrix precursor sol and heat treatment, has been followed. Several substrate hydrophilization methods have been tested and different substrates. Sol–gel infiltration of the opal template interstices with silica was achieved by dip-coating or micro-syringe application and it was followed by removal of the polymeric template. The concentration of the colloidal sol, containing polystyrene spheres of 235 or 460 nm in diameter, was optimized. The structural and optical properties of the opals and inverse opals have been studied by field emission scanning electron microscopy and optical reflectivity spectroscopy, in order to assess the relationship between their structure and the photonic properties obtained. By using borosilicate glass substrates hydrophilized with hydrochloric acid, colloidal photonic crystals of good quality have been obtained, with well ordered regions up to ～100 μm². By monitoring the effective refractive index change with relative humidity of the surrounding atmosphere, using spectroscopic ellipsometry with an environmental chamber, it was concluded that the present photonic crystals are suitable for humidity sensing applications.     

Crystal and molecular structure of bis(tetramethyl-ammonium)bis(maleonitriledithiolato)cuprate(II). Structure of C16H24CuN6S4

The crystal and molecular structure of the title compound, C₁₆H₂₄CuN₆S₄, is reported. The crystals are monoclinic: space groupP2₁/c,Z=4,a=13.230(3),b=11.518(9),c=16.269(6) Å,=95.07(2)°. The structure was solved by the heavy-atom method, and refined by full-matrix least squares toR=0.059 for 1907 unique diffractometer data. The anions have approximately 222 (D ₂) symmetry, with an angle of 41.14(1)° between the normals to planes of the ligands. The amino atoms of the cations have an approximate tetrahedral configuration. The anions are well separated from each other, the closest Cu-Cu distance being 7.811 (2) Å. The anionic units can be considered as being stacked alongb in columns. The metal atoms are not collinear along the stack axis, but form a kind of kinked chain.     

Stable and transient color centers in Gd3Ga5O12 crystals

The work is devoted to investigation of stable color centers (CC) that are created in Gd₃Ga₅O₁₂ (GGG) crystals under irradiation with γ-quanta (E = 1.25 MeV, D = 10⁵ Gy ) as well as transient CC created in the crystals under irradiation with pulsed electron beam (E = 0.25 MeV, pulse duration 10 ns, fluence 10¹² cm^-2, time interval of registration 0-500 ns). On the basis of the performed study of optical absorption spectra of the as-grown and irradiated crystals it was established the correlation between a defect subsystem of as-grown crystals and a type of CC induced by radiation in the crystals. The role of Ca²⁺ dopant ions in the processes of CC formation is examined. Models of the stable and transient CC are proposed. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal and molecular structure of diglycollic acid

The crystal structure of diglycollic acid has been determined by X-ray diffraction techniques and refined by full-matrix least squares, with three-dimensional counter data. The crystals are monoclinic:C2/c,a = 9·708(4),b = 3·938(3),c = 15·685(6) Å, = 112·01(3) °, andZ = 4. The finalR-factor for 673 observed reflections is 0·050. The carboxyl groups are related by a two-fold axis, parallel tob, passing through the central oxygen atom of the molecule. Polymeric chains of molecules are formed by hydrogen bonding. The intermolecular O—O separation is 2·668 Å, and is consistent with the observed infrared spectrum of solid diglycollic acid.     

Crystal and molecular structure of 1-amino-1-methylethylphosphonic acid monohydrate

The crystal and molecular structure of 1-amino-1-methylethylphosphonic acid monohydrate (C₃H₁₀NO₃P·H₂O) has been determined by single-crystal X-ray diffraction methods. The crystals are orthorhombic:Pna2₁,a=11.665(2),b=9.415(1),c=6.386(1) Å,Z=4. The structure was solved by the heavy-atom method and refined to a finalR=0.028. The molecule exists as a zwitterion, H ₃ ⁺ N-C-(CH₃)₂-PO₃₄H^–. There are six independent hydrogen bonds in the structure, three of the type N-HO with lengths 2.904(5), 2.745(6), and 2.765(5) Å and three of the type O-HO with lengths 2.754(4), 2.833 (7), and 2.548(5) Å.     

Crystal and molecular structure of 2-(1,3-benzothiazol-2-yl)-2-(4-tert-butylcyclohexylidene)ethanonitrile

The crystal and molecular structure of the title compound (C₁₉H₂₂N₂S) has been investigated by single crystal X-ray methods. The crystals are orthorhombic, space groupPbca, with cell dimensions:a=12.082(2)Å,b=11.460(2)Å,c=25.128(4)Å. The structure was solved by direct methods, and refined with 1225 independent reflections by a full-matrix, least-squares procedure, which converged toR=0.042. The benzene and thiazole planes are coplanar and the cyclohexane ring adopts a chair conformation.     

Crystal and molecular structure of 7α, 8α, 13-trihydroxy-marasman-5-oic acid γ-lactone,C15H22O4

The structure of the title compound has been investigated by X-ray diffraction methods. The crystals are monoclinic, space groupP2₁, with cell dimensions:a=9.802(3),b=6.192(1),c=12.392(2) Å, and=112.40(2)°. The structure was solved by direct methods, and refined with 1492 unique reflections by a full-matrix, least-squares procedure givingR=0.0450. Thetrans arrangement of H-8 and H-9 hydrogens as deduced from earlier¹H NMR experiments was fully confirmed by the X-ray investigations.