梯度结构胶体光子晶体的制备及光子禁带调节

以改进的对流自组装方法制备层数可控的胶体光子晶体, 并通过各向同性氧等离子体(O₂ Plasma)刻蚀构造出梯度结构, 进一步通过金(Au)及无定形硅(Si)的可控沉积调节梯度结构胶体光子晶体的光子禁带, 并将该梯度结构用于罗丹明B的荧光发射增强.     

光子晶体的制备及应用

光子晶体（PC）是具有光子带隙的周期性电介质结构，频率落在光子带隙中的光将被禁止传播。本文对光子晶体的能带结构、带隙的产生、制备方法及应用作了简要的介绍，重点介绍了光子晶体的制备技术及其在光电领域中的应用前景。     

In situ Detection of Cobaloxime Intermediates During Photocatalysis Using Hollow-Core Photonic Crystal Fiber Microreactors

Hollow-core photonic crystal fibers (HC-PCFs) provide a novel approach for in situ UV/Vis spectroscopy with enhanced detection sensitivity. Here, we demonstrate that longer optical path lengths than afforded by conventional cuvette-based UV/Vis spectroscopy can be used to detect and identify the Co^I and Co^II states in hydrogen-evolving cobaloxime catalysts, with spectral identification aided by comparison with DFT-simulated spectra. Our findings show that there are two types of signals observed for these molecular catalysts; a transient signal and a steady-state signal, with the former being assigned to the Co^I state and the latter being assigned to the Co^II state. These observations lend support to a unimolecular pathway, rather than a bimolecular pathway, for hydrogen evolution. This study highlights the utility of fiber-based microreactors for understanding these and a much wider range of homogeneous photocatalytic systems in the future.     

Structural and Electronic Peierls Distortions in the Elements (A): The Crystal Structure of Tellurium

The thermodynamically stable tellurium phase (standard conditions) in the trigonal α‐Se structure type may be understood to arise from a three‐dimensional Peierls distortion away from a simple cubic structure. Three‐dimensional electronic structure calculations from first principles reveal that the simple cubic structure exhibits partially filled bands which are folded back when using a hexagonal coordinate system with a tripled volume. The symmetry‐lowering transition from the cubic to the experimentally observed structure is paralled by a removal of band degeneracies and crossings, opening a band gap at the Fermi level.     

Emission and Energy Transfer Characteristics of Coumarin 6 Molecules Doped in Opal Polymer Photonic Crystal

The emission of coumarin 6(C-6) doped in opal polymethylmethacrylate(PMMA) photonic crystal(PC) was effectively manipulated. Meanwhile the energy transfer(ET) of C-6 in PCs, which are infiltrated with sulforhodamine B(S-B), was influenced by the concentration of energy acceptor in solution, the size of PMMA microsphere(SM) and the photonic stop band(PSB). The results should be beneficial to people to further understand the potential application of PCs in optoelectronic fields.     

分子印迹光子晶体传感芯片的制备及对邻苯二甲酸酯类化合物的检测

将光子晶体与分子印迹技术相结合,制备了一种反蛋白石结构的分子印迹光子晶体传感芯片,并将其应用于4种邻苯二甲酸酯类化合物的检测效果研究.分子印迹光子晶体传感芯片的制备过程包含3个步骤.首先,通过垂直沉降自组装方法制备SiO2蛋白石结构模版;随后,向蛋白石结构模板空隙中填充含有印迹分子邻苯二甲酸二异壬酯(DINP)的预聚液,引发光聚合;最后,移除SiO2结构模版及印迹分子,得到对邻苯二甲酸酯类化合物具有特异性识别功能的分子印迹光子晶体传感芯片.结果表明,传感芯片对待测物分子的识别过程可通过布拉格方程转换为可读的光学信号,当4种待测物浓度从1×10-5 mol/L增大到1 mol/L时,最大衍射峰位置发生20～40 nm的红移,且检测过程仅需6 min.检测芯片高度交联的聚合物结构令其具有较高的稳定性和重复利用性,5次检测后,芯片仍保持较好的传感性能.     

TiO2掺杂调控聚苯乙烯微球折射率及胶体光子晶体结构色

胶体光子晶体由于其可调变的结构色在绿色印刷、印染等领域备受关注,而其光子带隙的宽度和位置由光子晶体的晶格参数(晶面间距,通常受胶体微球尺寸影响)和介质的折射率决定。现有人工胶体光子晶体主要基于SiO_2和高分子(如聚苯乙烯(PS)等)微球的组装制备,由于胶体微球材质种类有限,折射率调控受限,因而目前调控胶体光子晶体结构色主要靠改变胶体微球的尺寸来实现。本文首先制备高折射率(2.6)的TiO_2纳米晶,在乳液聚合制备单分散的PS(折射率1.6)微球过程中,将所制备的TiO_2纳米晶掺杂于PS微球中,通过TiO_2的掺杂量有效调控胶体微球的折射率,进而实现胶体光子晶体的结构色调控。以多色胶体光子晶体微球的水溶液为墨水,采用彩色喷墨打印技术打印了电脑设计的光子晶体彩画。本文发展的光子晶体结构色调控新技术拓展了胶体光子晶体的应用。     

Single Crystal Growth and Crystal Structure of Anhydrous Mercury(I) Nitrate,Hg2(NO3)2

Polycrystalline anhydrous Hg₂(NO₃)₂ was prepared by drying Hg₂(NO₃)₂·2H₂O over concentrated sulphuric acid. Evaporation of a concentrated and slightly acidified mercury(I) nitrate solution to which the same volumetric amount of pyridine was added, led to the growth of colourless rod‐like single crystals of Hg₂(NO₃)₂. Besides the title compound, crystals of hydrous Hg₂(NO₃)₂·2H₂O and the basic (Hg₂)₂(OH)(NO₃)₃ were formed as by‐products after a crystallization period of about 2 to 4 days at room temperature. The crystal structure was determined from two single crystal diffractometer data sets collected at —100°C and at room temperature: space group P2₁, Z = 4, —100°C [room temperature]: a = 6.2051(10) [6.2038(7)]Å, b = 8.3444(14) [8.3875(10)]Å, c = 11.7028(1) [11.7620(14)]Å, ß = 93.564(3) [93.415(2)]°, 3018 [3202] structure factors, 182 [182] parameters, R[Fμ² > 2σ(Fμ²)] = 0.0266 [0.0313]. The structure is built up of two crystallographically inequivalent Hg₂²⁺ dumbbells and four NO₃^— groups which form molecular [O₂N‐O‐Hg‐Hg‐O‐NO₂] units with short Hg‐O bonds. Via long Hg‐O bonds to adjacent nitrate groups the crystal packing is achieved. The Hg‐Hg distances with an average of d(Hg‐Hg) = 2.5072Å are in the typical range for mercurous oxo compounds. The oxygen coordination around the mercury dumbbells is asymmetric with four and six oxygen atoms as ligands for the two mercury atoms of each dumbbell. The nitrate groups deviate slightly from the geometry of an equilateral triangle with an average distance of d(N‐O) = 1.255Å.     

Single Crystal Growth,Crystal Structure and Thermal Behaviour of Mercury(II) Pyrophosphate Dihydrate

Summary. Colourless single crystals of Hg₂P₂O₇(H₂O)₂ up to 0.4 mm in length were grown by a diffusion technique starting from aqueous solutions of Na₄P₂O₇ and Hg(NO₃)₂. The crystal structure is isotypic with that of Ca₂P₂O₇(H₂O)₂ and was determined from a four-circle diffractometer data set (space group , Z=2, a=6.9374(7), b=7.4396(8), c=7.9863(7)Å, =84.685(8), =75.158(8), =72.818(8)°, 2413 structure factors, 132 parameters, R[F ²>2(F ²)]=0.0181, wR(F ² all)= 0.0384). Hg₂P₂O₇(H₂O)₂ is composed of approximately eclipsed P₂O₇ ^4– anions and distorted [HgO₆] octahedra and [HgO₇] pentagonal bipyramids as the main building units. The structure is stabilized by inter-water hydrogen bonding and by hydrogen bonding between terminal pyrophosphate oxygen atoms and the water molecules. The P–O distances to the terminal oxygen atoms range from 1.501(4) to 1.536(3)Å, with an average of 1.522Å; the mean distance of 1.615Å to the bridging O atom is considerably longer with an (O–P–O) bridging angle of 123.44(19)°. Both Hg atoms have two short Hg–O bonds around 2.17Å and additional bonds ranging from 2.381(3) to 2.708(4)Å. Upon heating above 160°C, both crystal water molecules are released simultaneously and anhydrous Hg₂P₂O₇ is formed which is stable up to ca. 660°C. Above this temperature the material decomposes completely.     

Crystal structure and superconductive characteristics of Nb0.89Al0.11 oxynitrides

The crystal structure and superconductive characteristics of the niobium-aluminum oxynitrides were investigated. Single-phase products were successfully obtained starting from a cation ratio of Nb_0.89Al_0.11. The as-nitrided product crystallized in a cation-deficient rock-salt type structure with a chemical formula of (Nb_0.60Al_0.08□_0.32)(O_0.21N_0.79), while annealing at 1773 K under a nitrogen pressure of 0.5 MPa led to a highly crystallized product with a simple rock-salt type structure represented as (Nb_0.89Al_0.11)(O_0.17N_0.85). Upon post-annealing, both the critical temperature (T_c) and the superconductive volume fraction (V_SC) of the oxynitride were significantly enhanced from T_c≈7 K and V_SC=23% for the as-nitrided product to T_c=17.3 K and V_SC=91% for the post-annealed product.     

X–ray Single Crystal Structure and Raman Spectrum of Ammonium Hexafluoroarsenate

The structure of ammonium hexafluoroarsenate, NH₄AsF₆, has been determined by X‐ray diffraction using a single crystal grown from saturated solution in anhydrous HF. NH₄AsF₆ crystallizes rhombohedral with the KOsF₆ structure type, with a = 7.459(3) Å, c = 7.543(3) Å (at 200 K), Z = 3, space group (No. 148). No phase transition was observed in the 100 K–296 K temperature range. The structure is dominated by regular AsF₆ octahedra and disordered NH₄⁺ cations. Raman spectrum of a single crystal of NH₄AsF₆ shows the bands at 372 cm^?1, 572 cm^?1, 687 cm^?1 (AsF₆^?) and at 3240 cm^?1 and 3360 cm^?1 (NH₄⁺).     

Time-dependent Phosphorescence Color of Carbon Dots in Binary Salt Matrices through Activations by Structural Confinement and Defects for Dynamic Information Encryption

The emergence of time-dependent phosphorescence color (TDPC) materials has taken information encryption to high-security levels. However, due to the only path of exciton transfer, it is almost impossible to obtain TDPC for chromophores with a single emission center. Theoretically, in inorganic-organic composites, the exciton transfer of organic chromophores depends on the inorganic structure. Here, we assign two structural effects to inorganic NaCl by metal (Mg²⁺ or Ca²⁺ or Ba²⁺) doping, which triggers the TDPC performance of carbon dots (CDs) with a single emission center. The resulting material is used for multi-level dynamic phosphorescence color 3D coding to achieve information encryption. The structural confinement activates the green phosphorescence of CDs; while the structural defect activates tunneling-related yellow phosphorescence. Such simply doped inorganic matrices can be synthesized using the periodic table of metal cations, endowing chromophores with tremendous control over TDPC properties. This demonstration extends the design view of dynamic luminescent materials.     

Mn2O3单晶的合成、结构表征及磁性研究

通过助熔剂方法成功地培养了Mn2O3单晶体, 并对其进行了结构分析.     

Dissecting Noncovalent Interactions in Carboxyl-Functionalized Ionic Liquids Exhibiting Double and Single Hydrogens Bonds Between Ions of Like Charge

We show that the carboxyl-functionalized ionic liquid 1-(carboxymethyl)pyridinium bis(trifluoromethylsulfonyl)imide [HOOC-CH₂-py][NTf₂] exhibits three types of hydrogen bonding: the expected single hydrogen bonds between cation and anion, and, surprisingly, single and double hydrogen bonds between the cations, despite the repulsive Coulomb forces between the ions of like charge. Combining X-ray crystallography, differential scanning calorimetry, IR spectroscopy, thermodynamic methods and DFT calculations allows the analysis and characterization of all types of hydrogen bonding present in the solid, liquid and gaseous states of the ionic liquid (IL). We find doubly hydrogen bonded cationic dimers (c⁺=c⁺) in the crystalline phase. With increasing temperature, this binding motif opens in the liquid and is replaced by (c⁺−c⁺−a⁻ species, with a remaining single cationic hydrogen bond and an additional hydrogen bond between cation and anion. We provide clear evidence that the IL evaporates as hydrogen-bonded ion pairs (c⁺−a⁻) into the gas phase. The measured transition enthalpies allow the noncovalent interactions to be dissected and the hydrogen bond strength between ions of like charge to be determined.     

Single Crystal Growth and Crystal Structure of Mercurous Diarsenate(V), (Hg2)2(As2O7)

Polycrystalline mercurous diarsenate(V), (Hg₂)₂(As₂O₇), was prepared by a redox‐reaction between stoichiometric amounts of HgO and As₂O₃. Canary yellow single crystals were obtained by subsequent chemical transport reactions using HgCl₂ as transport agent [550 → 500 °C, 5 d, sealed and evacuated silica ampoules]. The crystal structure (orthorhombic, Pnma, Z = 4, a = 9.9803(8), b = 12.2039(10), c = 7.2374(6)Å) is composed of two crystallographically independent Hgequation/tex2gif-stack-1.gif dumbbells (d¯(Hg—Hg) = 2.5133Å) with a symmetric oxygen coordination sphere, and a diarsenate group with a staggered conformation and a bent bridging angle As—O—As = 121.0(7)°. The building units are arranged in a layer‐like assembly parallel to (010) and are connected via common oxygen atoms to form a three‐dimensional network.     

An Efficient Synthetic Method and Single Crystal Structure of a 2:3 Adduct of Cyclohexyl Isocyanide and Dimethyl Acetylenedicarboxylate

An efficient synthetic method and single crystal structure of a 2:3 adduct of cyclohexyl isocyanide and dimethyl acetylenedicarboxylate are described.     

The Crystal Structure of InGaO3(ZnO)4: A Single Crystal X‐ray and Electron Diffraction Study

The crystal structure of the mixed oxide InGaO₃(ZnO)₄ has been determined from electron diffraction and single‐crystal X‐ray diffraction data. The compound crystallises in a hexagonal space group (P6₃/mmc; No. 194), deduced from convergent beam electron diffraction (CBED). Single crystals of InGaO₃(ZnO)₄ were grown from a K₂MoO₄ flux in sealed platinum tubes. Single crystal structure refinement from XRD data [a = 3.2850(2) Å; c = 32.906(3) Å; Z = 2; 4232 data, R₁ = 0.0685] reveals a compound with oxygen anions forming a closest‐packed arrangement. Within this packing In³⁺ cations occupy octahedral interstices, forming layers of edge sharing octahedra. In between these layers are regions with composition [Zn₄GaO₅]⁺ forming a wurtzite type of structure. Inversions of the ZnO₄ tetrahedra occurs (i) at the InO₆ octahedral layer and (ii) halfway in the wurtzite type region, where the inversion boundary is built by Ga³⁺ in trigonal bipyramidal coordination with a long Ga–O_apical distance of 2.19(1) Å. The site occupation of Zn²⁺ and Ga³⁺, respectively, was confirmed by bond valence sum calculations. The compounds described here have the same structural charactistics as other known members with general formula ARO₃(ZnO)_m with m = integer.     

Growth and Thermal,Electrical, Structural Characterization of Mixed Hydrated Single Crystal

Mixed single crystal was made by mixing saturated aqueous solutions of NiSO₄ · 6H₂O and CuSO₄ · 5H₂O by volume (80:20) and the mixture was kept to form the crystals at room temperature by slow evaporation process. After some days, big pieces of greenish blue, dark colored crystals were grown. To determine the weight of NiSO₄ · 6H₂O and CuSO₄ · 5H₂O in the crystal, Ni-DMG complexiometrical and EDTA gravimetrical analysis was done respectively. From this analysis it was concluded that 5.8 molecules of water of crystallization is present in the mixed single crystal. The crystals were characterized by UV-Visible, FTIR and single crystal X-ray diffraction studies. From single crystal XRD lattice parameters have been calculated. All these structural analysis confirms formation of new single crystal. Further, DTA-TGA, dc electrical conductivity and dielectric constant studies were done from the room temperature to 400 °C.From DTA studies it was observed that 5.8 molecules of water of crystallization get dehydrated in four major steps at temperature 115 °C, 150 °C, 240 °C and 325 °C respectively corresponding to the detachment of 1 mole, 3 moles, 1 mole and 0.8 mole of water of crystallization. DC electrical conductivity and dielectric constant studies also show close agreement to the dehydration steps. The observed peaks in the conductivity verses temperature graph have been explained on the basis of release of water molecules and subsequent dissociation of these released water molecules into H⁺ and OH⁻ ions.     

Synthesis and Crystal Structure of Ammonium Cyanimide NH4HCN2

The compound NH₄HCN₂ ( 1 ) was prepared by the reaction of H₂CN₂ with liquid ammonia. The ammonium salt 1 was characterized by a low temperature single‐crystal X‐ray structure analysis. The anionic part of the structure consists of HCN₂^? anions, which are connected via N–H···N bonds (H···N distance: 2.47Å, DHA: 165°). The N–H···N hydrogen bonds of the ammonium ion to the anions range from 2.00 to 2.14Å (DHA = Donor···Acceptor angles: 165–176°), all N–H···N interactions together give rise to a three‐dimensional network. 1 decomposes quantitatively to dicyandiamide at room temperature.