Room-Temperature Synthesized Cd-Doped Cs3Cu2I5: Stable and Excitation-Wavelength Dependent Dual-Color Emission for Advanced Anti-Counterfeiting

With the development of intellectual properties, concern about advanced anti-counterfeiting is accumulating, which conventional single-modal luminescence can no longer satisfy. As one of rapidly developing 0D materials, copper-based perovskite shows great potential to realize multiple luminescent centers for complex emissions. In this work, Cd was doped into Cs₃Cu₂I₅ and showed resultant emission at 560 nm which surprisingly showed a red-shifted excitation peak from that of intrinsic self-trapped emission, resulting in excitation-wavelength dependent emission. When the excitation wavelength increased from 290 nm to 330 nm, the emission of Cd-doped Cs₃Cu₂I₅ changed from deep blue to cold white and finally yellow. Afterwards, Cd-doped Cs₃Cu₂I₅ was mixed with polystyrene to prepare anti-counterfeiting ink for silk-screen printing. Meanwhile, Cd-doped Cs₃Cu₂I₅ maintains outstanding stability after doping, no matter under ambient, continuous UV radiation or high-temperature environment. The intensity can be almost totally recovered after heating-and-cooling cycles. This study lays groundwork for future research into multiple luminescent center manipulation in 0D materials.     

Sodium in a strong magnetic field

We investigate the effects of a magnetic field with low to intermediate strength on several spectroscopic properties of the sodium atom. A model potential is used to describe the core of sodium, reducing the study of the system to an effective one-particle problem. All states with principal quantum numbers n = 3, 4, 5, 6 and 7 are studied and analysed. A grid of twenty values for the field strength in the complete regime B = 0 - 0.02 a.u. is employed. Ionisation energies, transition wavelengths and their dipole oscillator strengths are presented. Received 5 November 2002 Published online 4 February 2003     

Synthese und Kristallstruktur von Cs3Y7Se12

Synthesis and Crystal Structure of Cs₃Y₇Se₁₂ The oxidation of yttrium metal with selenium in the presence of CsCl (7 d, 700°C, evacuated silicia tubes) results in the formation of pale yellow, lath-shaped single crystals of Cs₃Y₇Se₁₂. The crystal structure (orthorhombic, Pnnm, Z = 2, a = 1272.8(3), b = 2627.7(5), c = 413.32(8) pm) consists of edge- and vertex-connected [YSe₆] octahedra forming a rocksalt-related network [Y₇Se₁₂]^3?. One-dimensional infinite channels along [001], apt to take up extra cations, provide coordination numbers of 6 and 7 + 1, respectively, for two crystallographically different Cs⁺.     

On the nature of the lowest 1/2<Superscript>-</Superscript> baryon nonet and decuplet<Superscript>⋆</Superscript>

From our recent study of properties of the lowest spin-parity 1/2^- baryons, N ^*(1535) and Δ^*(1620) , new pictures for the internal structure of the lowest 1/2^- baryon nonet and decuplet are proposed. While the lowest 1/2^- baryon nonet may have large diquark-diquark-antiquark component, the lowest 1/2^- baryon decuplet is proposed to have large vector-meson-baryon components. Evidence for “missing" members of the new pictures is pointed out and suggestions are made for detecting these predicted states from forthcoming experiments.     

Realistic nuclear Hamiltonian: Ab exitu approach

Fully-microscopic no-core shell model (NCSM) calculations of all stable s and p shell nuclei are used to determine a realistic NN   interaction, JISP16, describing not only the two-nucleon data but the binding energies and spectra of nuclei with A?16$A?16$ as well. The JISP16 interaction, providing rapid convergence of the NCSM calculations, is obtained in an ab exitu approach by phase-equivalent transformations of the JISP6 NN interaction.     

Scanning the optical characteristics of lead-free cesium titanium bromide double perovskite nanocrystals

Cs₂TiBr₆ nanocrystals (NCs) are a type of promising optoelectronic materials, owing to their high photoelectric properties and non-toxicity. Here, we synthesize the colloidal Cs₂TiBr₆ NCs using a hot-injection approach. The temperature-dependent absorption data shows that its energy band changes about 30 meV with temperature, reflecting that its energy band structure is much stable. The excitation intensity-dependent transient absorption data confirms its linear absorption cross-sections and carrier recombination rate constants, involving monomolecular and bimolecular recombination, which are all superior to those of conventional perovskite bromide counterparts. In addition, its nonlinear absorption cross-sections are also measured based on femtosecond Z-scan. Our results suggest that Cs₂TiBr₆ NCs can be extensively applied in the field of optoelectronics, owing to its excellent carrier dynamics and nonlinear optical properties.     

负电子亲和势GaN光电阴极铯吸附机理研究

为了得到铯吸附与阴极电子亲和势变化之间的定量关系,利用NEA光电阴极激活评估实验系统对GaN光电阴极进行了铯激活.根据半导体光电发射理论和双偶极层模型,通过对电子亲和势随铯覆盖度变化的实验结果进行拟合运算,得到电子亲和势与铯覆盖度之间的函数关系式.分析了铯的吸附机理,得到激活过程中铯的吸附过程与GaN材料有效电子亲和势下降之间的关系.实验表明:负电子亲和势GaN光电阴极材料在铯激活时光电流随着铯覆盖度的增加而从本底值增为极大值,激活过程中GaN电子能量分布曲线低动能截止点的位置决定于铯的覆盖度.当铯的覆盖度从0、1/2、2/3到1个单层变化时,低动能截止点依次向左移动,当覆盖度从0增加到1个单层时,低动能截止点向左移动了约3eV的距离.研究表明,低动能截止点左移本质上是由于对电子逸出起促进作用的有效偶极子[GaN(Mg):Cs]数量的增多造成的,有效偶极子数量的增多带来了材料表面真空能级的下降.     

[Cs(NTO)(H_2O)]配合物的合成及表征

本文首次用碳酸铯与NTO直接合成新的Cs NTO配合物。采用元素分析和化学分析法确定了配合物的组成。用红外光谱法 ,热分析法和X ray粉末衍射法进行了物理化学表征     

ChemInform Abstract: Crystal Structure of Cs2[B6H5(SCN)].

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.     

C60CH2结构和电子光谱的理论研究

用ＩＮＤＯ系列方法研究Ｃ６０ＣＨ２的两种结构，ＣＨ２加在两个六元环之间的键上为Ｃ２０构型，ＣＨ２加在一个五元环和一个六元环之间的键上为Ｃ５构型，计算表明，从总能量和ＬＵＭＯ－ＨＯＭＯ能级差看，Ｃ６０ＣＨ２的稳定结构应是Ｃ２０构型，该Ｃ２０异构体有类环丙结构（Ｃ１５－Ｃ３０桥键键长为０．１５５６ｎｍ，键序等于０．８６６３），其电子光谱计算结果与实验值符合较好。