Cathodic electrochemiluminescence at double barrier Al/Al2O3/Al/Al2O3 tunnel emission electrodes

Double insulating barrier tunnel emission electrodes were fabricated by adding a new pure aluminum layer upon oxidized aluminum electrodes by vacuum evaporation and thermally oxidizing the new aluminum layer in air at room temperature. Resulting Al/Al₂O₃/Al/Al₂O₃ electrodes allow the use of various aluminum alloys in the electrode body necessary for hardness or shaping ability of the electrode while obtaining the luminescence properties of pure aluminum oxide. During electrical excitation of luminescent labels by cathodic hot electron injection into aqueous electrolyte solution, the background noise is mainly based on high-field-induced solid-state electroluminescence and F-center luminescence of the outer aluminum oxide film. The more defect states and/or impurity centers the outer oxide film contains, the higher is the background emission intensity. The present electrode fabrication method provides a considerable improvement in signal-to-noise ratio for time-resolved electrochemiluminescence (TR-ECL) measurements when the original native oxide film of the electrode body contains luminescence centers displaying long-lived luminescence. The excellent performance of the present electrodes is demonstrated by extremely low-level detection of Tb(III) chelates, luminol, Pt(II) coproporphyrin and Tb(III) labels in an immunometric immunoassay by time-resolved electrochemiluminescence.     

Recent progress in quantitative and high spatial resolution AES

Progress in high resolution Auger electron spectroscopy (HR-AES or scanning Auger microscopy, SAM) during the past few years is characterized by the use of efficient field emission electron sources, parallel detection capabilities and improved data acquisition, storage and processing, thus enhancing spatial resolution (to about 10 nm), signal to noise figure and quantification of elements in different chemical bonding states, e.g. by routinely using factor analysis. Optimized ion sputtering facilities, particularly sample rotation, enable depth profiling with high, depth independent resolution. The basic features of SAM are discussed with respect to EPMA (electron probe micro-analysis), emphasizing fundamental limitations and future developments.     

A Semi‐Conductive Copper–Organic Framework with Two Types of Photocatalytic Activity

Based on the newly designed ligand 4′‐(3,5‐dicarboxyphenyl)‐4,2′:6′,4′′‐terpyridine (DCTP), a unique semi‐conductive 3D framework {[Cu^ΙCu^ΙΙ₂(DCTP)₂]NO₃?1.5 DMF}_n ( 1 ) with a narrow band gap of 2.1 eV, was obtained and structurally characterized. DFT calculations with van de Waals correction employed to explore the electronic structure of 1 , clearly revealed its semi‐conductive behavior. Furthermore, we found that 1 exhibits a superior band alignment with water to produce hydrogen and degrade organic pollutants. Without adding any photosensitizers, 1 displays an efficiently photocatalytic hydrogen production in water based on the photo‐generated electrons under UV/Vis light. 1 also exhibits excellent photo‐degradation of methyl blue under visible‐light owing to the strong oxidization of excited holes. It is the first example of MOFs with doubly photocatalytic activities related to photo‐generated electrons and holes, respectively.     

Molten salt flux synthesis and structure of the new layered uranyl tellurite, K4[(UO2)5(TeO3)2O5]

The reaction of UO₃ and TeO₃ with a KCl flux at 800 °C for 3 days yields single crystals of K₄[(UO₂)₅(TeO₃)₂O₅]. The structure of the title compound consists of layered, two-dimensional sheets arranged in a stair-like topology separated by potassium cations. Contained within these sheets are one-dimensional uranium oxide ribbons consisting of UO₇ pentagonal bipyramids and UO₆ tetragonal bipyramids. The ribbons are in turn linked by corner-sharing with trigonal pyramidal TeO₃ units to form sheets. The lone-pair of electrons from the TeO₃ groups are oriented in opposite directions with respect to one another on each side of the sheets rendering each individual sheet nonpolar. The potassium cations form contacts with nearby tellurite units and axial uranyl oxygen atoms. Crystallographic data (193 K, MoKα, ): triclinic, space group , , , , α=99.642(1)°, β=93.591(1)°, γ=100.506(1)°, , Z=1,R(F)=4.19% for 149 parameters and 2583 reflections with I>2σ(I).     

ZnS:Er电致发光中SiO2与ZnS电子加速能力的比较

在分层优化结构和固态阴极射线发光中, 从电极注入的电子经电子加速层加速后获得更高能量成为过热电子, 过热电子碰撞激发发光中心引起发光, 其中SiO2 在提高过热电子的能量方面有非常重要的作用. ZnS作为电子加速层时, 也发现了固态阴极射线发光, 但其发光的亮度及稳定性都不及 SiO2作为电子加速层的器件. 通过比较 ZnS：Er在正弦交流电驱动下的正负半周内的亮度变化, 得出ZnS与SiO2的电子加速能力的相对大小. 实验结果表明： SiO2的电子加速能力是ZnS的2.18倍.     

Intermodulation of transverse magnetoresistance oscillations in structures with strong intersubband interaction

In the Shubnikov–de Haas oscillation spectrum of doped InAs/AlSb structures, high-amplitude peaks are established at combination frequencies. It is demonstrated that they are caused by a significant contribution of intersubband scattering to the processes of electron-electron interaction. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 32–38, December, 2008.     

Spin Effects in Collisions of Electrons with Atoms and Molecules

IntroductionThedynamicsofelectron-atomandelectron-moleculecollisionshasbeenthefocusofmuchinterestinthepastbecauseofitsrelevanceingasdischargesandplasmas,includinggaslasers,orastrophysicalproblemsofpracticalinterest.Avarietyofinvestigationshavebeenperformedtostudysuchprocessesinsomedetail.Moresophisticatedexperimentalmethodsincludepolarization-correlationmeasurementstoobtaingeneralizedSTUparameters,spinasymmetrieswithpolarizedtargets(alsosuperelasticscatteringfromlaserexcitedtarget),opticalpar…