Luminescent Thin Films Enabled by CsPbX3 (X=Cl,Br, I) Precursor Solution

Inorganic cesium lead halide perovskite nanocrystals are candidates for lighting and display materials due to their outstanding optoelectronic properties. However, the dissolution issue of perovskite nanocrystals in polar solvents remains a challenge for practical applications. Herein, we present a newly designed one-step spin-coating strategy to prepare a novel multicolor-tunable CsPbX₃ (X=Cl, Br, I) nanocrystal film, where the CsPbX₃ precursor solution was formed by dissolving PbO, Cs₂CO₃, and CH₃NH₃X into the ionic liquid n-butylammonium butyrate. The as-designed CsPbX₃ nanocrystal films show high color purity with a narrow emission width. Also, the blue CsPb(Cl/Br)₃ film demonstrates an absolute photoluminescence quantum yields (PLQY) of 15.6 %, which is higher than 11.7 % of green CsPbBr₃ and 8.3 % of red CsPb(Br/I)₃ film. This study develops an effective approach to preparing CsPbX₃ nanocrystal thin films, opening a new avenue to design perovskite nanocrystals-based devices for lighting and display applications.     

Sphaerococcus coronopifolius (Rhodophyta,Gigartinales): a Mediterranean red alga with potential and applications in restoration

Abstract

Experimental studies conducted on some species of Mediterranean red algae allowed to identify Sphaerococcus coronopifolius Stackhouse as a valid alternative to the Pacific alga Gloiopeltis furcata (Postels & Ruprecht) J. Agardh, for the extraction of a material usable as natural consolidant and adhesive in the field of restoration. Promising results have been observed by comparing the extracts obtained from these two algae after the same extraction procedure. Chemical analysis (FTIR) revealed that S. coronopifolius has qualities similar to G. furcata. Even more promising results for S. coronopifolius compared to G. furcata were observed after the analysis of pH and conductivity, and the adhesion tests carried out on both extracts.     

基于吡嗪-吡啶-酰腙配体的三个配合物的制备及其荧光和光催化性能

合成了3个配合物{[Zn_3(L)_2(SO_4)_2(H_2O)_4]·H_2O}n(1)、{[Cd_2(L)_2(SO_4)(H_2O)]·H_2O}n(2)和{[Cd(L)I]·CH_3OH}n(3)(HL=N′-nicotinoylpyrazine-2-carbohydrazonamide),并通过单晶X射线衍射、红外、元素分析和粉末X射线衍射等手段进行表征。配合物1中,采用μ3-η1η1η1配位模式的SO_4~(2-)把Zn(Ⅱ)连接成无机网状二维平面(bc面),有机配体HL交错的分布在网状平面的两侧,这些二维层在分子间氢键的作用下形成三维超分子结构。配合物2是由配体HL连接[(Cd2)2(μ2-SO4)2]和Cd1两种节点形成的二维结构,相邻的二维层在π…π堆积作用下形成三维超分子结构。配合物3是一维的Z字链结构,这些一维链在氢键的连接作用下形成二维的超分子网络结构。光催化降解亚甲基蓝实验结果表明,在双氧水存在时配合物1~3均表现出很好的降解效果。     

Structural characterization and excited-state properties of luminescent <Emphasis Type="Italic">Tris</Emphasis>-(μ -3-methyl-5- trifluoromethylpyrazolato)trigold(I)

Tris-(-(3-methyl-5-trifluoromethylpyrazolato)-N:N)triangulo-trigold(I), (3,5-tfmpz)₃ Au₃, has been synthesized and exhibits a planar nine-member ring containing a central gold triangle with an average intramolecular Au–Au distance of 3.3455(8) Å. The complex crystallizes in the monoclinic space group Cc with a = 12.998(2) Å, b = 22.910 (3) Å, c = 7.217(1) Å, and = 104.781(1). The solid-state structure consists of sheets of (3,5-tfmpz)₃Au₃ units stacked in an offset fashion along the c axis such that one gold atom in each Au₃ unit (Au1) lies approximately over the midpoint of the Au1–Au3 edge of the triangle in the layer below it. The intermolecular Au–Au distances are between 3.880(1) and 4.023(1) Å, which are too long for there to be significant intertrimer bonding interaction suggesting that any supramolecular organization may be due to hydrogen-fluorine and fluorine-fluorine interactions between the molecules. The complex exhibits excitation-dependent emission at room temperature in the solid state. The structured higher energy emission (_em = 468, 517, and 556(sh) nm) is believed to be a ligand-centered ^* transition with a lower energy unstructured emission (_em = 658 nm) assigned to the classical Au–Au excited state transition.     

Synthesis,Structure and Luminescent Properties of [Zn（btzb）2Cl2]·2H2O [btzb = 1,2-Bis（5-tetrazolyl）benzene]

The title compound [Zn（btzb）2Cl2]·2H2O （1·2H2O, btzb = 1,2-bis（5-tetrazolyl）ben- zene） was synthesized in situ by the [2＋3] cycloaddition reaction of phthalonitrile with NaN3 in water in the presence of ZnCl2 under refluxing conditions. 1·2H2O crystallizes in the monoclinic system, space group P2 1/c with a = 9.0119（18）, b = 7.5566（15）, c = 18.076（5）A, β= 114.67（2）°, V= 1118.6（4）A^3, Z = 2, Dc = 1.784 g/cm^3, T= 223（2） K, C16H16N16O2Cl2Zn, Mr = 600.74, F（000） = 608, μ（MoKα） = 1.393 mm^-1, S = 1.081, R = 0.0306 and wR = 0.0669 for 1896 observed reflections with I 〉 2σ（I）. The Zn^2＋ ion of 1 is coordinated by four N atoms from two btzb ligands and two Cl atoms, forming a distorted octahedral coordination geometry. A number of intermolecular hydrogen bon- ding interactions between molecules 1 and/or the solvated water molecules result in a 3D hydrogen-bonded structure. The luminescent property of 1·2H2O was also investigated.     

Synthesis and Crystal Structure of a Novel Tetranuclear Complex [Pb4（HQ）6（NO3）2]

Reaction of 8-hydroxyquinoline （HQ） with Pb（NO3）2 in water resulted in the formation of a tetranuclear complex [Pb4（HQ）6（NO3）2] 1. It has been characterized by IR, elemental analyses and X-ray diffraction. Crystal data for this complex： triclinic system, space group P1, a = 9.7399（6）, b = 11.6535（8）, c = 12.6806（8） A, α = 62.8050（10）, β = 78.4910（10）, γ = 80.5490（10）°, C54H36N8O12Pb4, Mr= 1817.67, Z = 1, V = 1250.04（14）A^3, Dc = 2.415 g/cm^3,μ = 13.503 mm^-1, -12≤h≤8, -14≤k≤13, -15≤1≤15, F（000） = 840, Rint = 0.0217, R= 0.0348 and wR = 0.0927. X-ray crystal structure analysis revealed that in 1 each Pb（ II ） contains a stereo- chemically active lone pair of electrons. The Pb…C interaction, C-H……O weak interaction and π…π stacking interactions are observed in the complex. In the solid state, the complex possesses strong photoluminescent emission at 485 and 528 nm.     

Combined DFT and wave function theory approach to excited states of lanthanide luminescent materials: A case study of LaF3:Ce3+

Lanthanide luminescent materials play key roles in modern society, but their first-principles treatment remains a great challenge due to complex manifold of electronic excited states and the difficulty in performing excited state structural relaxations that is necessary to model luminescent properties. Herein, we propose a practical approach that combines embedded cluster model (ECM) based multi-configurational wave function theory (WFT) and occupancy constrained density-functional theory plus the Hubbard U correction (OC-DFT + U) to treat lanthanide doped luminescent materials, using LaF₃:Ce³⁺, a typical scintillator with low symmetry, as a case study. We show that the combined approach yields accurate absorption energies with an error on the order of 200 cm⁻¹, but the emission energies are significantly underestimated, the origin of which is further clarified by vibrationally resolved absorption and emission spectra calculation. This work demonstrates the possibility of combining ECM-based wave function theory and periodic DFT into a comprehensive computational scheme for lanthanide luminescent materials and highlights the limitations of the current implementation of OC-DFT + U for excited state structural optimization.     

New glass ceramics: an effective conjunction of wet chemistry synthesis and sintering

A glass with CdS nanoparticles was used simultaneously as a matrix for Ce-doped garnet and a yellow-red phosphor to prepare luminescent glass ceramics for the sources of white light. CdS nanoparticles compensate for the unbalanced Ce³⁺ emission spectrum of the composite material due to the addition of a red component. The synthesized composite material can be a tunable light converter due to altered luminescence spectra by changing the sintering conditions and excitation wavelength     

共轭聚合物发光和光伏材料研究进展

聚合物光电功能材料与器件因其广阔的应用前景,1990年以年来吸引了世界各国学术界的广泛关注和兴趣.聚合物光电子器件主要包括聚合物电致发光二极管、聚合物场效应晶体管和聚合物太阳能电池等,其使用的关键材料是共轭聚合物光电子材料,包括共轭聚合物发光材料、场效应晶体管材料和光伏材料等.本文主要对共轭聚合物电致发光材料和光伏材料的研究进展进行综述,介绍了这些聚合物材料的种类、结构和性质以及在聚合物电致发光器件和聚合物太阳能电池中的应用.并讨论了当前共轭聚合物光电子材料中的关键科学问题和今后的发展方向.