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Abstract: Luminescent CuInS2 nanocrystals have been synthesized in dodecanethiol using air-stable precursors. The nanocrystals were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. The optical properties of the CuInS2 nanocrystals can be controlled by changing the reaction conditions, such as reaction time, temperature, and addition of ligands. It was found that the steady-state photoluminescence spectrum of the close-packed CuInS2 nanocrystals on glass substrate peaked at longer wavelength than that of the colloidal ones and the close-packed nanocrystals possessed a shorter luminescence decay time. This behavior was explained on the basis of Förster resonant energy transfer due to the shorter distance between nanocrystals on substrate. [Copyright &y& Elsevier]

Abstract: Homogeneous pore-free Ba2NaNb5O15, KSr2Nb5O15, and 2·Na2O–PbO–6·Nb2O5 thin films were fabricated on sapphire substrates using the sol–gel technique. By controlling the gelation and coating process, thickness of thin films fabricated was controllable from ~40nm to ~10μm. Synthesized thin films possessed highly preferred orientated microstructure. Another advantage of this method is the subsequent heat treatment temperature dramatically decreased compared with other methods. This increases stoichiometry control and makes the large scale fabrication more feasible and efficient. [ABSTRACT FROM AUTHOR]

A zinc coordination polymer, Zn(IN)2 · 2H2O (1) (HIN = isonicotinic acid), has been synthesized and characterized by IR, elemental analysis, thermogravimetric analysis, and single crystal X-ray diffraction. This compound crystallizes in the chiral space group P62 with a = 15.512(3), b = 15.512(3), c = 6.262(2) Å, V = 1304.9(5) Å3, and Z = 3. The O and N atoms of the IN ligand are coordinated to a ZnII ion, locking the asymmetry of the IN ligand and transferring this asymmetry throughout the crystal structure to “direct” the formation of a chiral network. The structure of 1 is characteristic of a 3-D quartz-like framework, which contains hetero-chiral helical channels (pseudo-trigonal and hexagon channels) alternately along the c-axis. Compound 1 exhibits high stability and intense fluorescent emission at room temperature. [ABSTRACT FROM AUTHOR]

We report the synthesis and nanostructuraldevelopment of polycrystallineand single crystalline LiFePO4(LFP) nanostructures usinga solvothermal media (i.e., water–tri(ethylene glycol) mixture).Crystal phase and growth behavior were monitored by powder and synchrotronX-ray diffraction, as well as transmission electron microscopy (TEM),while particle morphologies were examined using scanning electronmicroscopy (SEM). Initially, thin (100 nm) platelets of Fe3(PO4)2·8H2O (vivianite, VTE)formed at short reaction times followed by the nucleation of LFP (20nm particles) on the metastable VTE surfaces. Upon decrease in pH,primary LFP nanocrystals subsequently aggregated into polycrystallinediamond-like particles via an oriented attachment (OA). With increasingreaction time, the solution pH further decreased, leading to a dissolution–recrystallizationprocess (i.e., Ostwald ripening, OR) of the oriented polycrystallineLFP particles to yield evenly sized, single crystalline LiFePO4. Samples prepared at short reaction durations demonstrateda larger discharge capacity at higher rates compared with the singlecrystalline particles. This is due to the small size of the primarycrystallites within larger secondary LiFePO4particles,which reduced the lithium ion diffusion path while subsequently maintaininga high tap density. Understanding the relationship between solutionconditions and nanostructural development as well as performance revealedby this study will help to develop synthetic guidelines to enableefficient lithium ion battery performance. [ABSTRACT FROM AUTHOR]

Li[Ni1/3Co1/3Mn1/3]O2(L333) has been successfully synthesized through a two-stepcoprecipitationand annealing method. Crystal phase and growth behavior were monitoredby X-ray diffraction (XRD), while particle morphologies were observedby SEM and TEM. The crystal growth mechanisms during the annealingprocess were interpreted, and the growth exponent and activation energyfor crystal growth were calculated. At low temperatures (e.g., 600°C), L333 crystals are quite small (ca. 14 nm). Significant crystalgrowth occurs above 750 °C with crystallite diameters increasingto 850 ± 10 nm after 3 h at 1000 °C. [ABSTRACT FROM AUTHOR]

Abstract: Three novel Cd(II)/Zn(II) compounds, [Cd2(poda)2(phen)3(H2O)] n ·nEtOH·3nH2O(1), [Zn(poda)2(bpy)(H2O)] n (2) and [Zn(Hpoda)2(bpy)](3) (H2poda=1,2-phenylenediacetic acid, phen=1,10-phenanthroline, bpy=2,2′-bipyridyl), have been synthesized and characterized by IR, TG, fluorescent spectrum and single-crystal X-ray diffraction techniques. In 1, poda2− anions link the adjacent Cd(II) centers to generate a 1D zigzag chain. Furthermore, an unprecedented four-footed “8-shaped” mixed water–ethanol (H2O)6(C2H5OH)2 cluster connects four double chains based on 1D zigzag chain into 3D supramolecular architecture. By bis(chelate–monodentate) fashion of poda2− ligand, compound 2 exhibits 1D zigzag chains, which forming a dense zipper-like 2D structure via strong π–π stacking interactions. Differed from 1 and 2, compound 3 has a mononuclear motif, and displays a 3D 6-connected α-Po net hydrogen-bonded topology. The structure-related solid-state fluorescence spectra of compounds 1 and 2 have been determined. [Copyright &y& Elsevier]

Reasonable quality Si-doped (1 1 2¯ 0) a-plane GaN have been grown by metalorganic chemical vapor deposition on (1 1¯ 0 2) r-plane sapphire substrates. Optical properties of the films were studied by photoluminescence spectroscopy. Our experimental results suggest that not VGa but the VGa–ON complex is the key defect responsible for yellow luminescence in GaN. At 12.9 K, free exciton A, donor bound exciton and exciton bound to neutral acceptor (Ix), which are similar to (0 0 0 1) GaN are observed. Different to (0 0 0 1) GaN, the longitudinal optical and transverse optical phonon replicas are found emerging simultaneously. Another peak at 3.42 eV is interpreted as donor–acceptor pair transition. [Copyright &y& Elsevier]

A new oxo-centered, carboxylate bridged trinuclear mixed-valence iron coordination polymer has been obtained under hydrothermal conditions, [(Fe III ) 2 Fe II ( μ 3 -O)(BNA) 6 ] n ( 1 ). Single crystal X-ray diffraction analysis of the black crystal reveals that three iron atoms occupy the vertices of a non-equilateral triangle with the Fe┄Fe distance in the range of 3.245 Å–3.343 Å and are bonded by the μ 3 -oxo-centered and BNA − ligands. The crystal belongs to the monoclinic crystal system with a  = 11.2904(6) Å, b  = 18.4960(11) Å, c  = 21.4349(12) Å, β  = 91.029(1), space group P 2 1 / c , GOF  = 1.028, final R 1  = 0.0156, w R 2 [ I  > 2 σ (I)] = 0.0405. [ABSTRACT FROM AUTHOR]

Hexagonal silicon (Si-IV) has recently attracted considerable research interest due to its extraordinary optical properties and possibility to convert into a direct semiconductor under strain with great potential for applications. However, the mechanical properties of Si-IV, which are critical for its applications, have not been experimentally studied yet. In this study, combining nanoindentation and in situ high-pressure synchrotron X-ray diffraction, we thoroughly investigated the mechanical properties of Si-IV. The results suggest that the elastic moduli and hardness of Si-IV are close to those of the common diamond cubic silicon. The similar mechanical properties of Si-IV and diamond cubic silicon are beneficial for integrating Si-IV into conventional Si-based devices using similar industrial processing and for its photovoltaic and optoelectronic applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Uniform hierarchical MoS 2 microspheres have been successfully synthesized via facile hydrothermal method with the aid of nonionic surfactant polyethylene glycol (PEG). The products were analyzed by XRD, SEM, TEM, XPS, BET and FTIR. Results indicated that PEG 6000 played a crucial role in the formation of the hierarchical MoS 2 microspheres and the obtained MoS 2 microspheres with diameters of 5–10 µm are organized by numerous ultrathin nanosheets assembled nanospheres. Interestingly, the MoS 2 architectures displayed remarkable performance towards removal of methylene blue (MB) from aqueous solution. More importantly, the hierarchical MoS 2 microspheres were easy to separate from the reaction system because of the hierarchical structure and large sizes. This resulting hierarchical MoS 2 microspheres are very promising adsorbent for adsorb organic pollutants and other applications. [ABSTRACT FROM AUTHOR]

Three ZnII and CdII complexes with Y-shaped dicarboxylate ligands, namely [Zn(L1)(2,2′-bpy)2(H2O)] ·2H2O ( 1), [Zn(L1)(bpp)(H2O)] ( 2), and [Cd(L1)(H2O)] ·H2O ( 3) [H2L1 = N-phenyliminodiacetic acid, 2,2′-bpy = 2,2′-bipyridine, bpp = 1,3-bis(4-pyridyl)propane] were synthesized and characterized by elemental analysis, IR spectroscopy single-crystal X-ray diffraction, and thermogravimetric analyses. Compound 1 shows an hydrogen-bonded 2D network, whereas compound 2 is an infinite 1D wavy chain structure, though O-H ···O hydrogen-bonded to form a 2D network. Compound 3 displays a 2D uninodal 3-connected Shubnikov plane net with the point symbol of (4.82). Moreover, the solid-state such as thermal stabilities and fluorescence properties of 1- 3 were also investigated. [ABSTRACT FROM AUTHOR]

Two new coordination polymers, namely, [Zn(bdc)(mbix)] n ( 1) and {[Cd2(bdc)2(mbix)2] ·H2O} n ( 2) [H2bdc = 5-hydroxylisophthalic acid, mbix = 1,3-bis(imidazol-1-yl-methyl)benzene], were obtained under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, as well as powder- and single-crystal X-ray diffraction. Compound 1 exhibits a 2D puckered layer with (4,4) topology, which is further interconnected by hydrogen bonding interactions leading to a 3D supramolecular architecture. Compound 2 features a 5-connected 3D network with bnn (46.64) topology based on the dinuclear CdII subunits. In addition, solid-state properties such as thermal stabilities and photoluminescent properties of compounds 1 and 2 were also investigated. [ABSTRACT FROM AUTHOR]

Two Cu(II)-complexes, {[Cu2(O2N-ipO)2(H2O)2]·(H2dpa)}n(1) and [Cu3(O2N-ipO)2(btb)]n(2) (O2N-ipO = deprotonated 5-NO2-2-hydroxylisophthalic acid, H2dpa = protonated dipyridin-4-ylamine and btb = 1,3-bis(1,2,4-triazol-l-yl)butane), were synthesized from anin situgenerated 5-NO2-2-hydroxylisophthalic acid and characterized by elemental analysis, FT-IR, single-crystal X-ray diffraction, PXRD, and TGA techniques. Complex1exhibits a 3-D alternate supramolecular network extended by the binuclear [Cu2(O2N-ipO)2]2−unit via intermolecular hydrogen bond interactions. Complex2features a 3-D pillar-layered network with a (44 × 610 × 8) (44 × 62)-fsctopology. Solid-state properties such as thermal stabilities and magnetic properties of the complexes were also investigated. Two new Cu(II)-complexes, {[Cu2(O2N-ipO)2(H2O)2]·(H2dpa)}n(1) and [Cu3(O2N-ipO)2(btb)]n(2), based onin situgenerated 5-NO2-2-hydroxyisophthalic acid were synthesized and characterized. Furthermore, solid-state properties such as thermal stabilities and magnetic properties of the complexes were also discussed. [ABSTRACT FROM AUTHOR]

The Mo-doped WSe2 nanolamellars have been successfully prepared via solid-state thermal (750 °C) reaction between micro-sized W, Mo with Se powders under inert atmosphere in a closed reactor and characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found that the morphologies of the as-prepared products changed from microplates to nanolamellars to aggregations composed of nanoparticles with the doping of Mo powders. And the sizes of crystallites evidently reduced while the contents of dopant increased within a certain limit (1 wt.%-7 wt.%). The tribological properties of the as-prepared products as additives in HVI750 base oil were investigated by UMT-2 multispecimen tribotester. The friction coefficient of the base oil containing Mo-doped WSe2 nanolamellars was lower and more stable than that of WSe2 nanolamellars. A combination of rolling friction, sliding friction, and stable tribofilm on the rubbing surface could further explain the good friction and wear properties of Mo-WSe2 nanoparticles as additives than that of WSe2. [ABSTRACT FROM AUTHOR]