Search

Three new perovskite-like hybrid iodobismuthates with two quaternary ammonium cations, namely (BnNEt3)3(Bi2I9) (1) (BnNEt3)4(Bi4I16) (2) and (n-Bu4N)2n(Bi4I14)n (3) (Bn = benzyl, n-Bu = n-butyl), have been synthesized by reacting BiI3 with the quaternary ammonium iodide in molar ratio 2:3 (1), 1:1(2), and 2:1 (3), respectively. All hybrids were characterized by elemental analysis, X-ray diffraction and UV–Vis spectroscopic analysis. Single-crystal X-ray diffraction revealed that hybrids 1 and 2 are di-nuclear and tetra-nuclear cluster structures respectively, while 3 is a polymeric chain structure based on a (Bi4I14) tetra-nuclear cluster unit. Their optical band-gaps have been determined as 2.19 eV(1), 2.16 eV(2), 2.02 eV(3), respectively. The optical band gaps exhibit a structure-related decrease from 1 to 3, in agreement with their color changes and the density functional theory (DFT) calculation results. The DFT calculations also reveal that there is a inversely proportional relationship between the optical Eg and the aggregation degree of the BiI6 octahedra in the hybrid iodobismuthate clusters.

Silver microparticles have inspired much research interest due to their enhanced properties for use in optical, electric, catalytic, and magnetic applications. One such use is as electrically conductive filler for printed electronics. A manufacturing approach has been developed to prepare low-curing-temperature silver pastes. Firstly, silver flakes were synthesized directly by a one-step aqueous-phase reduction reaction, using silver nitrate as silver salt precursor and iron(II) sulfate heptahydrate as reducing agent. Various silver flake samples were synthesized by controlling experimental parameters such as the reaction temperature, surfactant concentration, and reducing agent concentration. The obtained silver powders were characterized by x-ray diffraction analysis, scanning electron microscopy, and dynamic light scattering measurements. The results revealed that the morphology of the silver powders was a plate-like structure with diameter of 1 μm to 1.5 μm and thickness of 30 nm. The prepared silver flakes were then used directly without ball milling to prepare low-curing-temperature silver pastes. The bulk resistivity of a line screen-printed using silver paste containing 48 wt.% (34 ± 5 vol.%) silver flakes and cured at 140°C for 30 min in air was about (1.773 ± 0.118) × 10−6 Ω m. More importantly, the prepared screen-printed patterns exhibited excellent durability in terms of peel strength and folding endurance.

A series of strongly phosphorescent copper(I) halide complexes, namely [Cu(μ-X)POP]2 (X = Cl (1), Br (2), I (3), Br0.5Cl0.5 (4), POP = bis[2-(diphenylphosphino)phenyl]ether), have been synthesized by reacting CuX with the diphosphine ligand in 1:1 molar ratio. All complexes were characterized by spectroscopic analysis (IR, UV–Vis), elemental analysis, and photoluminescence study. Single-crystal X-ray diffraction revealed that complex 2 is a dinuclear structure which is constructed by two μ-X bridges and two POP ligands as μ2 bridges. Other complexes were determined as isologues of complex 2 by powder X-ray diffraction and elemental analysis. All complexes exhibit intense blue-green phosphorescence with a lifetime of ~1 μs in the solid state. The halogen-mixed complex presents a lightly change in the luminescence comparing to that of parent complexes. The excited states of all complexes have been assigned as halide-to-ligand charge transfer state mixed metal-to-ligand charge transfer character based on the time-dependent density functional theory calculations. All complexes are thermally stable according to thermogravimetric analysis so that they are suitable for applying in luminescent devices.

s During the course of reinvestigating the reactions of iodate anion and lanthanide cations under different conditions, the single-crystal structure of Eu(IO 3 ) 3 (H 2 O)·H 2 O ( 1 ) and a series of corresponding nanoplate materials were obtained. X-ray single-crystal diffraction reveals that 1 is characterized as a two-dimensional inorganic layered structure with an unprecedented binodal (3, 5)-connected net of (3·4·5)(3 2 ·4 2 ·5·6 3 ·7 2 ) topology. A simple solution reaction method has also been founded for synthesizing corresponding Ln(IO 3 ) 3 (H 2 O)·H 2 O (Ln = Nd, Eu, Gd, Tb, Dy) nanoplate materials. PXRD measurements have shown that the size of the particles increases along with the raise of the adopted synthesis temperature. Their thermogravimetric analyses (TGA) and luminescence properties have also been discussed. The strong red/yellow emission for materials of Eu III /Tb III was observed, respectively.

The LaBr3:Ce crystal is difficult to grow although it has very excellent scintillation properties. In this paper, the LaBr3:Ce crystals have been grown by the self-seeding Bridgman technique, and the ⌀ 38 mm × 50 mm LaBr3:Ce single crystal ingot has been achieved. It is found that the orientation of the crystal growth has a close relationship with the lowering velocity and the quartz ampule shape. The 1 mm/h lowering velocity is very helpful for the [001] direction to dominate the crystal growth under the certain ampule shape, thus avoiding the crystal crack effectively, and the 0.5 mm/h lowering velocity is helpful for the [100] direction to dominate the crystal growth under the same ampule shape. On this basis, the mechanism of the nuclei competition is discussed. The UV luminescence and the X-ray excited emission spectra of the LaBr3:Ce crystal have also been investigated.