Hydrothermal synthesis of [C6H16N2][In2Se3(Se2)]: A new one-dimensional indium selenide

A new organically templated indium selenide, [C₆H₁₆N₂][In₂Se₃(Se₂)], has been prepared hydrothermally from the reaction of indium, selenium and trans-1,4-diaminocyclohexane in water at 170 °C. This material was characterised by single-crystal and powder X-ray diffraction, thermogravimetric analysis, UV-vis diffuse reflectance spectroscopy, FT-IR and elemental analysis. The compound crystallises in the monoclinic space group C2/c (a=12.0221(16) Å, b=11.2498(15) Å, c=12.8470(17) Å, β=110.514(6)°). The crystal structure of [C₆H₁₆N₂][In₂Se₃(Se₂)] contains anionic chains of stoichiometry [In₂Se₃(Se₂)]²⁻, which are aligned parallel to the [1 0 1] direction, and separated by diprotonated trans-1,4-diaminocyclohexane cations. The [In₂Se₃(Se₂)]²⁻ chains, which consist of alternating four-membered [In₂Se₂] and five-membered [In₂Se₃] rings, contain perselenide (Se₂)²⁻ units. UV-vis diffuse reflectance spectroscopy indicates that [C₆H₁₆N₂][In₂Se₃(Se₂)] has a band gap of 2.23(1) eV.     

Compounds in the system Cu2SeAs2Se3

The phase diagram Cu₂SeAs₂Se₃ was investigated by thermal and X-ray methods. Cu₂Se has a limited solubility for As₂Se₃ (5 mole% at 769 K). The stoichiometric compound Cu₃AsSe₃ exists between 696 and 769 K. Cu₄As₂Se₅, a phase at 66.6 mole% Cu₂Se, decomposes peritectically at 746 K. The narrow homogeneity range (4 mole% at 683 K) extends far into the ternary space. CuAsSe₂ also decomposes peritectically at 683 K. A degenerated eutectic between CuAsSe₂ and As₂Se₃ was found at 641 K. Single crystals of Cu₄As₂Se₅ were grown in a salt melt. A metastable modification of the high-temperature phase Cu₃AsSe₃ can be obtained by quenching. Cu₄As₂Se₅ (space group R3, lattice constants a = 1404.0(1) pm, c = 960.2(1) pm), Cu₆As₄Se₉, obtained by Cambi and Elli, and Cu₇As₆Se₁₃ of Takeuchi and Horiuchi are different versions of a sphalerite-type compound with a broad homogeneity range in the system CuAsSe. CuAsSe₂ is possibly monoclinic with lattice parameters of a = 946.5(1) pm, b = 1229.3(1) pm, c = 511.7(1) pm, and β = 98.546(4)°. The enthalpy of mixing of Cu₂Se and As₂Se₃ in the liquid state is endothermic.     

离子液体电沉积CuIn_xGa_(1-x)Se_2薄膜(英文)

采用循环伏安法(CV)对离子液体Reline中三元CuCl2+InCl3+SeCl4体系和四元CuCl2+InCl3+GaCl3+SeCl4体系的电化学行为进行了研究。研究表明,In3+并入三元CIS(Cu-In-Se)薄膜体系和Ga3+并入四元CIGS(Cu-In-Ga-Se)薄膜体系均有两种途径:一是发生共沉积,二是直接还原。利用电感耦合等离子体发射光谱(ICP)和扫描电镜(SEM)对沉积电势、镀液温度和主盐浓度对CIGS薄膜组成、镀层表面形貌的影响进行了测试,结果表明通过工艺参数的选择可以控制Ga/(Ga+In)和CIGS薄膜组成并得到化学计量比为Cu1.00In0.78Ga0.27Se2.13的薄膜。     

Etude du diagramme ternaire CuInSe2ZnSeIn2Se3

The system CuInSe₂ZnSeIn₂Se₃ has been investigated. A large domain of thiogallate-type compounds was found with a number of cation vacancies less or equal to that of ZnIn₂Se₄ compound. A study with a least-squares method was performed on the experimental parameters a and c and relations with the compositions are given. The blende-structure model with cation vacancies was used for evaluation of the vacancy radius [r₁ = (0.97 ± 0.05) Å] in the thiogallate compounds.     

A crystallographic description of experimentally identified formation reactions of Cu(In,Ga)Se2

This work describes solid-state reactions for the formation of the chalcopyrite compounds CuInSe₂, CuGaSe₂ and Cu(In,Ga)Se₂ on atomic scale. The most important chalcopyrite formation reactions which were identified by the authors by real-time in situ X-ray diffraction in preceding experiments are (A) CuSe+InSe→CuInSe₂, (B) Cu₂Se+2 InSe+Se→2 CuInSe₂ and (C) Cu₂Se+In₂Se₃→2 CuInSe₂. During the selenistaion of a metallic precursor containing gallium a separate fourth reaction occurs: (D) Cu₂Se+Ga₂Se₃→2 CuGaSe₂. The quaternary compound is finally formed by interdiffusion of CuInSe₂ with CuGaSe₂ (E). These five reactions differ in their activation energy and reaction speed. We explain these differences qualitatively by analysing the involved crystal structures for each reaction. It turns out that all reactions involved in the formation of Cu(In,Ga)Se₂ are promoted by epitaxial relations, which facilitates the formation of polycrystalline thin films at temperatures much below those necessary for single crystal growth. Recommendations for the growth of larger grains of Cu(In,Ga)Se₂ containing fewer defects are given.     

V2Cu3Ga8, Mo2Cu3Ga8 and W2Cu3Ga8—New compounds with a novel order variant of a bcc packing and motifs of self-similarity

Single crystals of the new compounds TM₂Cu₃Ga₈ (TM=V, Mo, W) were synthesised from the elements. Structure determinations of the isotypic compounds (cI104, space group , Z=8; Mo₂Cu₃Ga₈: a=11.9171(10) Å, 613 refl., 23 param., R₁(F)=0.022, wR₂(F²)=0.047; W₂Cu₃Ga₈: 11.9248(8) Å, 346 refl., 23 param., R₁(F)=0.048, wR₂(F²)=0.086; V₂Cu₃Ga₈: 11.7861(14) Å, 374 refl., 24 param., R₁(F)=0.033, wR₂(F²)=0.081) showed a new cubic structure type which can be classified as an ordered defect variant of a bcc packing with a^′=4a: [(TM)₂(Cu)₃(□)₃][Ga₈]. The coordination polyhedra of the transition metals consist of Ga₈-cubes with 3 sides capped by Cu leading to coordination number 11. The arrangement of the TMGa₈Cu₃-polyhedra is in a way they form itself a 3-fold capped cube. All compositions were confirmed by EDX measurements.     

离子液体电沉积CuInxGa1-xSe2薄膜

采用循环伏安法(CV)对离子液体Reline中三元CuCl₂+InCl₃+SeCl₄体系和四元CuCl₂+InCl₃+GaCl₃+SeCl₄体系的电化学行为进行了研究。研究表明,In³⁺并入三元CIS(Cu-In-Se)薄膜体系和Ga³⁺并入四元CIGS(Cu-In-Ga-Se)薄膜体系均有两种途径：一是发生共沉积,二是直接还原。利用电感耦合等离子体发射光谱(ICP)和扫描电镜(SEM)对沉积电势、镀液温度和主盐浓度对CIGS薄膜组成、镀层表面形貌的影响进行了测试,结果表明通过工艺参数的选择可以控制Ga/(Ga+In)和CIGS薄膜组成并得到化学计量比为Cu_1.00In_0.78Ga_0.27Se_2.13的薄膜。     

Phase formation, crystal structures and magnetic properties of perovskite-type phases in the system La2Co1+z(MgxTi1−x)1−zO6

Perovskite-type cobaltates in the system La₂Co_1+z(Mg_xTi_1−x)_1−zO₆ were studied for z=0≤x≤0.6 and 0≤x<0.9, using X-ray and neutron powder diffraction, electron diffraction (ED), magnetic susceptibility measurements and X-ray absorption near-edge structure (XANES) spectroscopy. The samples were synthesised using the citrate route in air at 1350 °C. The space group symmetry of the structure changes from P2₁/n via Pbnm to R3¯c with both increasing Mg content and increasing Co content. The La₂Co(Mg_xTi_1−x)O₆ (z=0) compounds show anti-ferromagnetic couplings of the magnetic moments for the Co below 15 K for x=0, 0.1 and 0.2. XANES spectra show for the compositions 0≤x≤0.5 a linear decrease in the L₃/(L₃+L₂) Co-L_2,3 edge branching ratio with x, in agreement with a decrease of the average Co ion spin-state, from a high-spin to a lower-spin-state, with decreasing nominal Co²⁺ ion content.     

Synthesis and characterization of quaternary chalcogenides InSn2Bi3Se8 and In0.2Sn6Bi1.8Se9

Quaternary chalcogenides InSn₂Bi₃Se₈ and In_0.2Sn₆Bi_1.8Se₉ were synthesized on direct combination of their elements in stoichiometric ratios at T>800 °C under vacuum. Their structures were determined with X-ray diffraction of single crystals. InSn₂Bi₃Se₈ crystallizes in monoclinic space group C2/m (No. 12) with a=13.557(3) Å, b=4.1299(8) Å, c=15.252(3) Å, β=115.73(3)°, V=769.3(3) Å³, Z=2, and R₁/wR₂/GOF=0.0206/0.0497/1.092; In_0.2Sn₆Bi_1.8Se₉ crystallizes in orthorhombic space group Cmc2₁ (No. 36) with a=4.1810(8) Å, b=13.799(3) Å, c=31.953(6) Å, V=1843.4(6) Å³, Z=4, and R₁/wR₂/GOF=0.0966/0.2327/1.12. InSn₂Bi₃Se₈ and In_0.2Sn₆Bi_1.8Se₉ are isostructural with CuBi₅S₈ and Bi₂Pb₆S₉ phases, respectively. The structures of InSn₂Bi₃Se₈ and In_0.2Sn₆Bi_1.8Se₉ feature a three-dimensional framework containing slabs of NaCl-(311) type with varied thicknesses. Calculations of the electronic structure and measurements of electrical conductivity indicate that these materials are semiconductors with narrow band gaps. Both compounds show n-type semiconducting properties with Seebeck coefficients −270 and −230 μV/K at 300 K for InSn₂Bi₃Se₈ and In_0.2Sn₆Bi_1.8Se₉, respectively.     

XANES Study on the Generation and Distribution of Holes via Ca Substitution and O Doping in Cu(Ba0.8Sr0.2)2(Yb1−xCax)Cu2O6+z

Generation of holes is facilitated in the Cu(Ba_0.8Sr_0.2)₂ (Yb_1−xCa_x)Cu₂O_6+z (Cu-1212) system by two independent ways, i.e., by Ca substitution (0≤x≤0.35) and O doping (0<z<1). The distribution of holes between the CuO₂-(Yb_1−xCa_x)-CuO₂ block containing two identical superconductive CuO₂ planes and the “charge-reservoir” block consisting of a single CuO_z chain has been quantitatively investigated by means of O K-edge and Cu L_2,3-edge X-ray absorption near-edge structure (XANES) spectroscopy. The resultant values for the CuO₂-plane hole concentration are compared with those calculated employing the bond-valence-sum (BVS) method from the neutron powder diffraction (NPD) data previously reported for the same samples. The results of the two methods are in good agreement. The two independent hole-doping ways are found to result in different distributions of holes over the crystal, i.e., different ratios of hole numbers at the CuO₂ plane and the CuO_z chain. With Ca substitution holes are directed efficiently into the CuO₂ plane, while for O doping holes are more homogeneously distributed between the CuO₂ plane and the CuO_z chain. Moreover, the value of T_c at a fixed CuO₂-plane hole concentration is shown to be higher for Ca-substituted than for O-doped samples.     

Effects of Mn substitution on the structure and properties of chalcopyrite-type CuInSe2

Mn-doped CuInSe₂ compounds (CuIn_1−xMn_xSe₂, x=0.0125–0.20 and Cu_1−yIn_1−yMn_2ySe₂, 2y=0.0125–0.60) were synthesized by high-temperature solid-state reactions. Single phase materials with chalcopyrite structure persist up to 0.10 and 0.20 doping for CuIn_1−xMn_xSe₂ and Cu_1−yIn_1−yMn_2ySe₂, respectively. The chalcopyrite and sphalerite phases co-exist in the Cu_1−yIn_1−yMn_2ySe₂ system for 2y=0.25–0.50. Attempts to introduce greater manganese content, x=0.15–0.20 for CuIn_1−xMn_xSe₂ and 2y=0.60 for Cu_1−yIn_1−yMn_2ySe₂, result in partial phase segregation. For the single-phase samples, the lattice parameters of both systems increase linearly with manganese concentration and thus follow Vegard's law. The temperature of the chalcopyrite–sphalerite phase transition is decreased by manganese substitution for all single-phase samples. The bandgap of the materials remains around 0.9 eV. Additionally, the Mn-doped CuInSe₂ compounds display paramagnetic behavior, whereas pure CuInSe₂ is diamagnetic at 5–300 K. All the CuIn_1−xMn_xSe₂ and Cu_1−yIn_1−yMn_2ySe₂ compounds with chalcopyrite structure show antiferromagnetic coupling and measured effective magnetic moments up to 5.8 μ_B/Mn.     

Room temperature formation of Cu3Se2 by solid-state reaction between α-Cu2Se and α-CuSe

Upon being brought into contact with each other, α-Cu₂Se and α-CuSe pellets reacted entirely forming Cu₃Se₂ at room temperature. After 10 days, the reaction was almost completed. Weight measurements revealed that copper atoms migrated from α-Cu₂Se to α-CuSe. Solid-state reactions were also observed in the (α-Cu₂Se+Cu₃Se₂) and (α-Cu₂Se+CuS) systems, but not in the (Cu₃Se₂+α-CuSe), (Cu₂S+CuS) and (α-CuSe+Cu₂S) systems. Therefore, the high ionic conductivity of copper ions in α- and β-Cu₂Se is considered to be responsible for the solid-state reactions observed in these systems.     

A re-interpretation of the crystal structure of ‘(NH4)2(NH3)[Ni(NH3)2Cl4]’ in terms of (NH4)2−2z[Ni(NH3)2]z[Ni(NH3)2Cl4]

A re-interpretation and re-evaluation of single-crystal X-ray diffraction data of a previously reported ‘(NH₄)₂(NH₃)[Ni(NH₃)₂Cl₄]’ (J. Solid State Chem. 162 (2001) 254) give a new formula (NH₄)_2−2z[Ni(NH₃)₂]_z[Ni(NH₃)₂Cl₄] with z=0.152. This new formula results from defects in an idealized ‘(NH₄)₂[Ni(NH₃)₂Cl₄]’ basic structure, where two adjacent NH₄⁺ cations are replaced by one Ni(NH₃)₂²⁺ unit. Cl⁻ anions from the basic structure complete the coordination sphere of the new Ni²⁺ to [Ni(NH₃)₂Cl₄]²⁻.     

Synthesis and structural study of a new NASICON-type solid solution: Li1−xLax/3Zr2(PO4)3

A new complete solid solution of NASICON-type compounds between LiZr₂(PO₄)₃ and La_1/3Zr₂(PO₄)₃ was evidenced with the general formula Li_1−xLa_x/3Zr₂(PO₄)₃ (0?x?1). These phases were synthesized by a complex polymerizable method and structurally characterized from Rietveld treatment of their X-ray and neutron powder diffraction data. This solid solution results from the substitution mechanism Li⁺→1/3La³⁺+2/3□ leading to an increase of the vacancies number correlated to an increase of the La content. According to this substitution mechanism, the general formula can then be written Li_1−xLa_x/3□_2x/3Zr₂(PO₄)₃ (0?x?1) in order to underline the correlation between the La content and the vacancies rate. For all the compounds, the structure is clearly related to that of the NASICON family with three crystallographic domains evidenced. For 0?x?0.5, all the members adopt at high temperature the typical NASICON-type structure (s.g. R3¯c), while at lower temperature, their structure distorts to a triclinic form (s.g. C 1¯), as observed for LiZr₂(PO₄)₃ prepared above 1100 °C. Moreover, in this domain, the reversible transition is clearly soft and the transition temperature strongly depends of the x value. For 0.6?x?0.9, the compounds crystallize in a rhombohedral cell (s.g. R3¯), while for x=1, the phase La_1/3Zr₂(PO₄)₃ is obtained (s.g. P3¯, Z=6, a=8.7378(2) Å, c=23.2156(7) Å).This paper is devoted to the structure analysis of the series Li_1−xLa_x/3Zr₂(PO₄)₃ (0?x?1), from X-ray and neutron powder thermo diffraction and transmission electron microscopy (TEM) studies.     

Phase diagram of the In3As2Se6-In3As2S3Se3 system

The In₃As₂Se₆-In₃As₂S₃Se₃ system has been investigated by methods of physicochemical analysis (DTA, X-ray powder diffraction, MSA) and by microhardness and density measurements. The phase diagram of the system, which is the quasi-binary section of the As-In-S-Se quaternary system, has been constructed. The region of the In₃As₂Se₆-based solid solutions is extended to 7 mol %, and the In ₃As₂S₃Se₃-based region to 15 mol %. A new quaternary compound In₆As₄S₃Se₉ is found in the system. Original Russian Text ? I.I. Aliev, R.S. Magammedragimova, A.A. Farzaliev, Dzh. Veliev, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 4, pp. 691–694.     

Electronic and structural properties of A Al2Se4 (A=Ag, Cu, Cd, Zn) chalcopyrite semiconductors

We have studied the structural and electronic properties of defect chalcopyrite semiconductors A Al₂Se₄ (A=Ag, Cu, Cd, Zn) using density functional theory (DFT) based first principle technique within tight binding linear muffin-tin orbital (TB-LMTO) method. Our calculated structural parameters such as lattice constants a and c, tetragonal distortion (η=c/2a) are in good agreement with experimental work. Anion displacement parameters, bond lengths and bulk modulus are also calculated. Our band structure calculation suggests that these compounds are direct band gap semiconductors having band gaps 2.40, 2.50, 2.46 and 2.82 eV for A Al₂Se₄ (A=Ag, Cu, Cd, Zn) respectively. Calculated band gaps are in good agreement with other experimental and theoretical works within LDA limitation. We have made a quantitative estimation of the effect of p-d hybridization and structural distortion on the electronic properties. The reduction in band gap due to p-d hybridization is 19.47%, 21.29%, 0% and 0.7% for A Al₂Se₄ (A=Ag, Cu, Cd, Zn) respectively. Increment of the band gap due to structural distortion is 11.62%, 2.45%, 2.92% and 9.30% in case of AgAl₂Se₄, CuAl₂Se₄, CdAl₂Se₄ and ZnAl₂Se₄ respectively. We have also discussed the bond nature of all four compounds.     

Synthesis,Characterization, and DNA Binding Properties of Dinuclear Copper（Ⅱ） Complex [Cu2（TATP）2（L-Leu）2（CIO4）2]2·2H2O

A dinuclear copper（Ⅱ） complex[Cu2（TATP）2（L-Leu）2（CIO4）2]2·2H2Owas synthesized and characterized, where, TATP=1,4,8,9-tetraazatriphenylene, and L-Leu=L-leucinate. The complex was crystallized in the triclinic space group P1, with two independent molecules in a unit cell. Two Cu（Ⅱ） ions in each complex [Cu2（TATP）2（L-Leu）2（CIO4）2] molecule were found to be in different coordination geometries, i.e., Cu2 or Cu4 of a distorted square-pyramidal geometry coordinated with two nitrogens of TATP, the amino nitrogen and one carboxylate oxygen of L-Leu and one oxygen of perchlorate, and Cul or Cu3 with an octahedral geometry coordinated with the above stated similar coordinated atoms, and another carboxylate oxygen of L-Leu coordinating to Cu2 or Cu4. The complex can interact with CT-DNA by an intercalative mode and cleave pBR322 DNA in the presence of ascorbate.     

Synthesis, crystal structure and magnetic properties of the spin ladder compounds La2(Cu1−xZnx)2O5 and La8(Cu1−xZnx)7O19

The influence of Zn-doping on the crystal structure and magnetic properties of the spin ladder compounds La₂Cu₂O₅ (4-leg) and La₈Cu₇O₁₉ (5-leg) have been investigated. The La₂(Cu_1−xZn_x)₂O₅ and La₈(Cu_1−xZn_x)₇O₁₉ solid solutions were obtained as single phases with x=0-0.1 via the solid-state reaction method in the temperature range between 1005-1010 °C and 1015-1030 °C in oxygen and air atmospheres, respectively. The lattice parameters a and c of the monoclinic crystal structures as well as the unit cell volume V increase with increasing x, while b and β decrease for both series. The magnetic susceptibilities χ of both series show a very similar behavior on temperature as well as on Zn-doping, which is supposed to be due to the similar Cu-O coordination in both La₂Cu₂O₅ and La₈Cu₇O₁₉. For low Zn-doping (x?0.04), a spin-chain like behavior is found. This quasi-one-dimensional behavior is strongly suppressed in both series for x?0.04. Here, the maximum (characteristic for spin chains) in χ(T) disappears and χ(T) decreases monotonically with increasing temperature.     

Ab-initio study of the structural, linear and nonlinear optical properties of CdAl2Se4 defect-chalcopyrite

The complex density functional theory (DFT) calculations of structural, electronic, linear and nonlinear optical properties for the defect chalcopyrite CdAl₂Se₄ compound have been reported using the full potential linearized augmented plane wave (FP-LAPW) method as implemented in the WIEN2k code. We employed the Wu and Cohen generalized gradient approximation (GGA-WC), which is based on exchange-correlation energy optimization to calculate the total energy. Also we have used the Engel-Vosko GGA formalism, which optimizes the corresponding potential for band structure, density of states and the spectral features of the linear and nonlinear optical properties. This compound has a wide direct energy band gap of about 2.927 eV with both the valence band maximum and conduction band minimum located at the center of the Brillouin zone. The ground state quantities such as lattice parameters (a, c, x, y and z), bulk modulus B and its pressure derivative B′ are evaluated. We have calculated the frequency-dependent complex ε(ω), its zero-frequency limit ε₁(0), refractive index n(ω), birefringence Δn(ω), the reflectivity R(ω) and electron energy loss function L(ω). Calculations are reported for the frequency-dependent complex second-order nonlinear optical susceptibilities. We find opposite signs of the contributions of the 2ω and 1ω inter/intra-band to the imaginary part for the dominant component through the wide optical frequency range.     

Synthesis,structure and magnetism of a one-dimensional silicotungstate array: K3H4Cu0.5{Cu[Cu7.5Si2W16O60(H2O)4(OH)4]2} · 9H2O

A structurally distinct, multi-copper(II)-substituted silicotungstate K₃H₄Cu_0.5{Cu[Cu_7.5Si₂W₁₆O₆₀(H₂O)₄(OH)₄]₂} · 9H₂O (1) has been synthesized and characterized by FT-IR spectroscopy, elemental analysis, variable-temperature magnetic measurements, electron spin resonance, and X-ray diffraction. Green crystalline plates of 1 were obtained by the reaction of K₈[γ-SiW₁₀O₃₆] · 12H₂O with 8 equiv. of Cu(II) in a 50% ethylene glycol solution. A cationic copper center connects the terminal oxygen atoms of neighboring polyanions, resulting in a one-dimensional structure. Magnetic susceptibility measurements indicate weak ferromagnetic superexchange between the Jahn–Teller-distorted S = 1/2 Cu(II) centers.