Ba2In2Q5 (Q = S,Se): Synthesis,Crystal Structures,Electronic Structures,and Optical Properties

Two ternary metal chalcogenides, Ba₂In₂Q₅ (Q = S, Se) were successfully synthesized by solid‐state reactions. They are isostructural and crystallize in the orthorhombic space group Pbca (no. 61). Both of them have a similar three‐dimensional (3D) framework structure, which is composed of [InQ₄] (Q = S, Se) tetrahedra that are alternatingly connected on layer in the ab plane, with Ba²⁺ cations arranged between In–S or In–Se layers for electric charge balance. The measured Raman and IR spectra show that title compounds have broad transparency range up to 20 μm. From the UV/Vis/NIR diffuse reflectance spectra, it can be seen that the bandgaps of Ba₂In₂S₅ and Ba₂In₂S₅ are 2.47 eV and 2.12 eV, which are larger than these of the calculation values (Ba₂In₂S₅, 2.362 eV and Ba₂In₂Se₅, 1.908 eV), respectively. The calculated partial densities of states indicate that the bandgaps are determined by the interaction of S‐3p and In‐5s (Ba₂In₂S₅) or Se‐4p and In‐5s (Ba₂In₂Se₅), respectively. The calculated birefringences (Δn) are about 0.03 (Ba₂In₂S₅) and 0.05 (Ba₂In₂Se₅) as the wavelength above 1 μm, respectively.     

In-situ Synthesis of the Thinnest In2Se3/In2S3/In2Se3 Sandwich-Like Heterojunction for Photoelectrocatalytic Water Splitting

The efficient utilization of solar energy for photoelectrocatalytic (PEC) water splitting is a feasible solution for developing clean energy and alleviating environmental issues. However, as the core of PEC technology, the existing photoanode catalysts have disadvantages such as poor photoelectrocatalytic conversion efficiency, low conductivity of photogenerated carriers, and instability. Here, we report the ultrathin two-dimensional sandwich-like (SW) heterojunction of In₂Se₃/In₂S₃/In₂Se₃ (SW In₂S₃@In₂Se₃) for the first time for PEC water splitting. Our findings identify the efficient separation of electrons and holes by constructing SW In₂S₃@In₂Se₃ heterojunction. The in situ synthesis of ultrathin nanosheet arrays by using surface substitution of Se atom to epitaxially grow cell In₂Se₃ maximizes the contact area of heterogeneous interface and accelerates the transmission of charge carrier. Benefitting from the unique structure and composition characteristic, SW In₂S₃@In₂Se₃ displays excellent performance in PEC water splitting. The photocurrent density of SW In₂S₃@In₂Se₃ reaches 8.43 mA cm⁻² at 1.23 V_RHE. Compared with In₂S₃, the SW In₂S₃@In₂Se₃ photoanode has nearly 12 times higher PEC performance, which represents the best performance among the In₂S₃-based photoanode heterojunction reported so far. The evolution rate of O₂ reaches 78.8 μmol cm⁻² h⁻¹, and the photocurrent has no apparent variety within 24 h.     

Non‐centrosymmetric Selenides AZn4In5Se12 (A=Rb,Cs): Synthesis,Characterization and Nonlinear Optical Properties

Two new non‐centrosymmetric polar quaternary selenides, namely, RbZn₄In₅Se₁₂ and CsZn₄In₅Se₁₂, have been synthesized and structurally characterized. They exhibit a 3D diamond‐like framework (DLF) consisting of corner‐shared MSe₄ (M=Zn/In) tetrahedra, in which the A⁺ ions are located. Both compounds are thermally stable up to 1300 K and exhibit large transmittance in the infrared region (0.65–25 μm) with measured optical band gaps of 2.06 eV for RbZn₄In₅Se₁₂ and 2.11 eV for CsZn₄In₅Se₁₂. Inspiringly, they exhibit a good balance between strong second harmonic generation (SHG) efficiency (3.9 and 3.5×AgGaS₂) and high laser‐induced damage thresholds (13.0×AgGaS₂). Theoretical calculations based on density functional theory (DFT) methods confirm that such strong SHG responses originate from the 3D DLF structure.     

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.     

Electrosynthesis of a Defective Indium Selenide with 3D Structure on a Substrate for Tunable CO2 Electroreduction to Syngas

Syngas (CO/H₂) is a feedstock for the production of a variety of valuable chemicals and liquid fuels, and CO₂ electrochemical reduction to syngas is very promising. However, the production of syngas with high efficiency is difficult. Herein, we show that defective indium selenide synthesized by an electrosynthesis method on carbon paper (γ‐In₂Se₃/CP) is an extremely efficient electrocatalyst for this reaction. CO and H₂ were the only products and the CO/H₂ ratio could be tuned in a wide range by changing the applied potential or the composition of the electrolyte. In particular, using nanoflower‐like γ‐In₂Se₃/CP (F‐γ‐In₂Se₃/CP) as the electrode, the current density could be as high as 90.1 mA cm^?2 at a CO/H₂ ratio of 1:1. In addition, the Faradaic efficiency of CO could reach 96.5 % with a current density of 55.3 mA cm^?2 at a very low overpotential of 220 mV. The outstanding electrocatalytic performance of F‐γ‐In₂Se₃/CP can be attributed to its defect‐rich 3D structure and good contact with the CP substrate.     

Preparation and properties of two indium antimony selenides

Crystals of antimony-doped In₂Se₃ were grown by the Bridgeman method. This compound, whose composition is In_1.8Sb_0.2Se₃, appears to be isostructural with In_1.9As_0.1Se₃. The refined unit cell parameters are a = 3.97(1), c = 18.87(1) Å. Orthorhombic crystals of InSbSe₃ were grown from an isothermal melt. The refined unit cell parameters are a = 9.43(1), b = 14.02(5), and c = 3.96(1) Å. These parameters agree with those determined for α-InSbSe₃ by other studies. The observed densities measured by a hydrostatic technique are 5.98(3) g/cm³ for In_1.8Sb_0.2Se₃ and 6.07(2) g/cm³ for InSbSe₃. The room temperature dc resistivity for In_1.8Sb_0.2Se₃ has been found to be 4.4 × 10⁴ Ω-cm, whereas that of InSbSe₃ has been found to be 15.2(1) Ω-cm. A resistivity versus temperature study has beenn carried out for InSbSe₃ between 230 and 400°K. Optical studies indicate that In_1.8Sb_0.2Se₃ is an n-type semiconductor with a band gap of 1.1 eV and InSbSe₃ is a p-type semiconductor with a band gap of 0.92 eV.     

Graphene oxides as support for the synthesis of nickel sulfide–indium oxide nanocomposites for photocatalytic,antibacterial and antioxidant performances

NiS (nickel sulfide)–In₂O₃ (indium oxide) nanostructures and NiS–In₂O₃ decorated on graphene oxide (GO) were demonstrated by ultrasonic/hydrothermal method. The structural study demonstrates the preparation of bixbyite and hexagonal phase of In₂O₃ and NiS for all of the synthesized catalysts. The band gap of the synthesized catalyst was determined to be in the range of 2.30–3.00 eV. A morphological evaluation by field emission scanning electron microscopy of NiS–In₂O₃ decorated on graphene oxide shows support for the NiS–In₂O₃ on the graphene oxide layer. Different test parameters were performed to study the phase and morphology. The particle sizes of the In₂O₃, NiS–In₂O₃ and NiS–In₂O₃/GO nanocomposites were 56.0, 62.0 and 66.0 nm, respectively. The photocatalytic performance of NiS–In₂O₃/GO nanocomposites was examined for the degradation of methylene blue dye under a UV lamp. The prepared sample shows 98.25% photocatalytic degradation within 40 min and at pH 9. With the presence the NiS and GO, the photo-degradation capacities of In₂O₃ and NiS–In₂O₃ are improved owing to the low band gap being calculated in UV–vis DRS analysis. The high ratio of NiS causes the highest photocatalytic properties of NiS–In₂O₃ nanocomposites owing to the enhancement of charge separation efficiency and generation of hydroxyl radicals. This study presents a facile and low-cost method to prepare highly active NiS–In₂O₃/GO nanocomposites. The antibacterial data indicate the significant properties of NiS–In₂O₃/GO nanocomposites for this study.     

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。     

Der Einfluß von Sauerstoff,Wasser, Chlor und Brom auf den Transport von Kohlenstoff in fluorhaltigen Systemen

Quaternary System ZnSe - Cr₂Se₃ - In₂Se₃ The section Zn_1-xIn_0.667xCr₂Se₄ and ZnCr_2-yIn_ySe₄ as well as some samples of compositions outside these joins of the quaternary system ZnSe Cr₂Se₃ - In₂Se₃ were studied with the help of X-ray Guinier photographs of quenched samples. Whereas no detectable amounts of chromium can be incorporated into ZnIn₂Se₄ of the thiogallate structure (MnIn₂Te₄ type) in the case of the spinel ZnCr₂Se₄ (a = 1050.0 pm) up to 21 mol % of chromium and up to 20 mol % of zinc can be substituted by indium. However, spinel type solid solutions with larger indium content (up to a = 1076 pm) are formed by coincident substitution of both zinc and chromium corresponding to Zn_1-xIn_0.667xCr_2-yIn_ySe₄ (0 < x + y < 0.6) with indium in both tetrahedral and octahedral lattice sites.     

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。     

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.     

Zur Kenntnis des quaternären Systems Zn?In?S?Se Der Schnitt ZnIn2S4?Znln2Se4?In2S3?In2Se3

The Quaternary System ZnIn₂S₄? ZnIn₂Se₄? In₂Se₃? In₂S₃ The title system has been investigated on the indium rich side (ratio In/Zn ≥ 2) on samples quenched from 800°C to room temperature using x-ray methods. In this section 7 different phases could be identified the phase borders of which are given. ZnIn₂S₄-type and thiogallate type mixed crystals only show a small region of homogeneity while the monophase region of spinel type mixed crystals in the indiumsulfide rich part of the phase diagram has a larger extension. There is a new trigonal compound ZnIn₂S₂Se₂ (a_hex = 3.937, c_hex = 31.97 Å) with a large region of homogeneity. In the indiumselenide rich part there are two new phases: (i) Zn_0.4In₂Se_3.4 with unknown structure and (ii) a ternary phase of unknown structure in the system In₂S_3?xSe_x for 2.1 ≤ x ≤ 2.7.     

Phase Instability in van der Waals In2Se3 Determined by Surface Coordination

van der Waals In₂Se₃ has attracted significant attention for its room-temperature 2D ferroelectricity/antiferroelectricity down to monolayer thickness. However, instability and potential degradation pathway in 2D In₂Se₃ have not yet been adequately addressed. Using a combination of experimental and theoretical approaches, we here unravel the phase instability in both α- and β′-In₂Se₃ originating from the relatively unstable octahedral coordination. Together with the broken bonds at the edge steps, it leads to moisture-facilitated oxidation of In₂Se₃ in air to form amorphous In₂Se_3−3xO_3x layers and Se hemisphere particles. Both O₂ and H₂O are required for such surface oxidation, which can be further promoted by light illumination. In addition, the self-passivation effect from the In₂Se_3−3xO_3x layer can effectively limit such oxidation to only a few nanometer thickness. The achieved insight paves way for better understanding and optimizing 2D In₂Se₃ performance for device applications.     

Phase study of the system Li2Se-In2Se3

The binary system Li₂Se-In₂Se₃ was investigated in the range of 40 to 100 mol% In₂Se₃ by thermoanalytical and X-ray methods. The system is characterized by two eutectic points. Beside the two binary components and the known ternary compound LiInSe2 another ternary compound crystallizes in this binary system at 83.3 mol% In₂Se₃. This compound was identified as LiIn₅Se₈. In contrast to (Cu, Ag)^IB₅ ^IIIC₈ ^VI compounds such as CuIn₅S₈ [1] it does not crystallize in the spinel structure. LiIn₅Se₈ shows a stratified structure. The melting point was determined to be at 810°C. Starting from room temperature up to the melting point no phase transitions were observed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Enhanced Electrocatalytic Performance of a Porous g‐C3N4/Graphene Composite as a Counter Electrode for Dye‐Sensitized Solar Cells

A porous graphitic carbon nitride (g‐C₃N₄)/graphene composite was prepared by a simple hydrothermal method and explored as the counter electrode of dye‐sensitized solar cells (DSCs). The obtained g‐C₃N₄/graphene composite was characterized by XRD, SEM, TEM, FTIR spectroscopy, and X‐ray photoelectron spectroscopy. The results show that incorporating graphene nanosheets into g‐C₃N₄ forms a three‐dimensional architecture with a high surface area, porous structure, efficient electron‐transport network, and fast charge‐transfer kinetics at the g‐C₃N₄/graphene interfaces. These properties result in more electrocatalytic active sites and facilitate electrolyte diffusion and electron transport in the porous framework. As a result, the as‐prepared porous g‐C₃N₄/graphene composite exhibits an excellent electrocatalytic activity. In I^?/I₃^? redox electrolyte, the charge‐transfer resistance of the porous g‐C₃N₄/graphene composite electrode is 1.8 Ω cm², which is much lower than those of individual g‐C₃N₄ (70.1 Ω cm²) and graphene (32.4 Ω cm²) electrodes. This enhanced electrocatalytic performance is beneficial for improving the photovoltaic performance of DSCs. By employing the porous g‐C₃N₄/graphene composite as the counter electrode, the DSC achieves a conversion efficiency of 7.13 %. This efficiency is comparable to 7.37 % for a cell with a platinum counter electrode.     

Cobalt-doped chalcopyrites CuInSe2: the synthesis and magnetic properties

Two series of samples of the composition CuIn_1?XCo_XSe₂ (m-series) and Cu_1?X/2In_1?X/2Co_XSe₂ (d-series) were prepared by solid-state synthesis and their magnetic properties were investigated. It was shown that cobalt is much better incorporated into the chalcopyrite matrix of the d-series samples, thus providing the onset of paramagnetic properties. Quenching allows the concentration of the incorporated cobalt to increase, which leads to the onset of weak ferromagnetism.

     

Structural investigation of the Cu2Se-In2Se3-Ga2Se3 phase diagram, X-ray photoemission and optical properties of the Cu1−z(In0.5Ga0.5)1+z/3Se2 compounds

Structures of compounds in the Cu₂Se-In₂Se₃-Ga₂Se₃ system have been investigated through X-ray diffraction. Single crystal structure studies for the so-called stoichiometric compounds Cu(In,Ga)Se₂ (CIGSe) confirm that the chalcopyrite structure (space group I4¯2d) is very flexible and can adapt itself to the substitution of Ga for In. On the other hand a structure modification is evidenced in the Cu_1−z(In_0.5Ga_0.5)_1+z/3Se₂ series when the copper vacancy ratio (z) increases; the chalcopyrite structure turns to a modified-stannite structure (I4¯2m) when z≥0.26. There is a continuous evolution of the structure from Cu_0.74(In_0.5Ga_0.5)_1.09Se₂ to Cu_0.25(In_0.5Ga_0.5)_1.25Se₂ ((i.e. Cu(In_0.5Ga_0.5)₅Se₈), including Cu_0.4(In_0.5Ga_0.5)_1.2Se₂ (i.e. Cu(In_0.5Ga_0.5)₃Se₅). From this single crystal structural investigation, it is definitively clear that no ordered vacancy compound exists in that series. X-ray photoemission spectroscopy study shows for the first time that the surface of powdered Cu_1−z(In_0.5Ga_0.5)_1+z/3Se₂ compounds (z≠0) is more copper-poor than the bulk. The same result has often been observed on CIGSe thin films material for photovoltaic applications. In addition, optical band gaps of these non-stoichiometric compounds increase from 1.2 to 1.4 eV when z varies from 0 to 0.75.     

Large optical Kerr effect in bulk GeSe2–In2Se3–CsI chalcohalide glasses

Third-order nonlinear optical properties of GeSe₂–In₂Se₃–CsI chalcogenide bulk glasses are studied by Standard pico-second (ps) time-resolved optical Kerr effect (OKE) technique. The obtained χ⁽³⁾ and n₂ at 1064 nm of the glass 72.25GeSe₂–23.75In₂Se₃–5CsI are as large as 10.07 × 10⁻¹² esu and 6.5 × 10⁻¹⁸ m²/W, respectively, more than twice that of As₂S₃ glass. The relationship between glass compositions and the third-order nonlinear optical responses was analyzed by Raman spectra in terms of structural evolution. It is suggested that the tetrahedral units ([GeSe₄] and [InSe₄]) play an important role in the ultrafast third-order nonlinear optical responses of these chalcohalide glasses.     

Synthesis,Structural, and Optical Characterization of a New Europium(II) Tin Selenide,Eu8(Sn4Se14)(Se3)2 with a (Sn4Se14)12– Building Block

A new phase in europium‐tin‐chalcogenide chemistry has been prepared using the reactive flux method: Eu₈(Sn₄Se₁₄)(Se₃)₂. The compound crystallizes in the orthorhombic space group P2₁2₁2 with cell parameters a = 11.990(2) Å, b = 16.425(4) Å, c = 8.543(1) Å, and Z = 2. Eu₈(Sn₄Se₁₄)(Se₃)₂ is a three dimensional structure with Eu^II cations linked together with an unusual (Sn₄Se₁₄)^12– anionic unit and (Se₃)^2– chains. UV‐VIS‐NIR band‐gap analysis shows that these black metallic crystals are likely semiconductors with an optical band‐gap of 1.07 eV.     

Wide-coverage and Efficient NIR Emission from Single-component Nanophosphors through Shaping Multiple Metal-halide Packages

Wide-coverage near infrared (NIR) phosphor-converted LEDs possess promising potential for practical applications, but little is developed towards the efficient and wide-coverage NIR phosphors. Here, we report the single-component lanthanide (Ln³⁺) ions doped Cs₂M(In_0.95Sb_0.05)Cl₆ (M=alkali metal) nanocrystals (NCs), exhibiting emission from 850 to 1650 nm with high photoluminescence quantum yield of 20.3 %, which is accomplished by shaping the multiple metal halide octahedra of double perovskite via the simple alkali metal substitution. From Judd-Ofelt theoretical calculation and spectroscopic investigations, the shaping of metal halide octahedra in Cs₂M(In_1−xSb_x)Cl₆ NCs can break the forbidden of f-f transition of Ln³⁺, thus increasing their radiative transition rates and simultaneously boosting the energy transfer efficiency from host to Ln³⁺. Finally, the wide-coverage NIR LEDs based on Sm³⁺, Nd³⁺, Er³⁺-tridoped Cs₂K_0.5Rb_0.5(In_0.95Sb_0.05)Cl₆ NCs are fabricated and employed in the multiplex gas sensing and night-vision application.