On the oxygen content in sputtering InOx film for transparent electronics

Transparent undoped semiconductor indium oxide films were deposited by using a long-throw rf magnetron sputtering at room temperature. It was found that the variation of oxygen content in sputtering gas has a strong influence on the microstructure and electrical properties of the films. The electrical resistivity varying from 3.5 × 10^?2 to 4.7 × 10⁴ Ω-cm for oxygen contents ranging from 0 to 50 % was obtained. The optical band gap decreases as the oxygen content increases, and the average visible transmittance of the indium oxide is ~85 %. To put into practice, the as-sputtered indium oxide was employed as a channel of thin film transistors on glass substrate with a channel length, 6 μm, and a channel width, 20 μm. Its saturation mobility, threshold voltage, and on/off ratio were obtained to be 9.4 V^?1 s^?1, 1.5 V, and 2.2 × 10⁷. To approach a flexible device, a plastic substrate is employed to replace the rigid substrate, glass; and the relative parameters, saturation mobility, threshold voltage, and on/off ratio, are also measured to be 8.2 V^?1 s^?1, 1.8 V, and 1.4 × 10⁶, respectively.     

Low-temperature sintering and electrical properties of Co-doped ZnO varistors

ZnO–Bi₂O₃–B₂O₃-based varistors doped with each kind of cobalt oxides were prepared by conventional ceramic processing. The effects of CoO, Co₂O₃ and Co₃O₄ on the microstructure and the electrical characteristics of varistor samples sintered at 880 °C were investigated separately. Analysis of microstructure indicated the cobalt cations were distributed both in grain regions and grain boundary regions and no crystalline phases containing cobalt were detected in XRD patterns for the samples with various cobalt oxides. All these cobalt oxides could effectively enhance the varistor performance by effectively increasing the nonlinear coefficient and lowing the leakage current, while the breakdown voltage fields increased slightly. Capacitance–voltage characteristics showed the potential barriers of varistor samples increased with the addition of each cobalt oxide. It was found that the addition of same amount of cobalt cations in various cobalt oxides had a different effect on the varistor samples. Best electrical properties were obtained for the varistor sample containing Co₃O₄, in which the nonlinearity coefficient is 28.5, the leakage current density is 3.4 μA and the breakdown voltage field is as low as 260 V/mm.     

Effect of Co doping on the structure,optical and magnetic properties of LaAlO3 thin films

LaAl_1?x Co _x O₃ (x = 0, 0.05 and 0.10) thin films were fabricated on quartz substrates by sol–gel method. X-ray diffraction data indicate that all thin films belong to perovskite LaAlO₃, and there is no secondary phase. Two obvious Raman peaks are observed in the Raman spectra, and the 113 cm^?1 peak is assigned to A₁ mode of perovskite LaAlO₃ while the 696 cm^?1 peak is caused by the Co–O stretching vibration. The band gap of the films decreases from 5.66 to 5.40 eV with the Co composition increasing from 0 to 10 %. The magnetization of the films was investigated, and it enhances significantly with increase of the Co content.     

热湿地区室内挥发性有机物多源散发研究现状

分析热湿地区室内空气污染现状,对影响热湿地区室内空气污染因素的独特特征进行总结。介绍国内外热湿环境下挥发性有机物多污染源散发机制的研究现状,指出湿热条件下室内装修家具等具有多污染源的挥发性有机物散发模型及环境影响因素研究的不足,提出对室内温度场、风速场、湿度场、污染物浓度分布进行模拟仿真的研究方向。     

Preparation and Characterization of TiN Seed Layer in All-Conductive Multilayer Structure for Coated Conductors

TiN films were successfully prepared on biaxially textured Ni-5 at.%W substrates by pulsed laser deposition (PLD), serving as a seed layer of an all-conductive architecture, i.e., SrRuO₃(SRO)/TiN, for coated conductors. The structure and surface morphology of the TiN films were noticeably affected by the substrate temperature and pulse repetition rate. The subsequent conductive SRO and superconducting YBCO layer were deposited on the best sample of TiN buffered Ni-5 at.%W substrates. X-ray diffraction analysis confirmed that the biaxial textures were transferred from the TiN seed layer to the SRO cap layer and YBCO film with excellent out-of-plane and in-plane textures. The superconducting transition curves and the temperature-dependent resistivity of YBCO films on all-conductive buffer and on the traditional insulated CeO₂/YSZ/Y₂O₃ were also investigated.     

Stability and Half-Metallicity of the (001) and (111) Surfaces of RbN with Cesium Chloride Structure

Using the full-potential local orbital minimum-basis method, we study the electronic and magnetic properties of relaxed (001) and (111) surfaces of the bulk RbN within the framework of density functional theory. It is shown that the Rb(N)-terminated (001) surfaces as well as the N-terminated (111) surface are the half-metallicity, while the Rb-terminated (111) surface loses the half-metallicity. The atomic magnetic moments at the N-terminated (001) and Rb(N)-terminated (111) surfaces increase considerably with respect to the corresponding bulk values. In addition, calculations reveal the half-metallicity of the N-terminated (111) surface is more robust than the bulk RbN due to its larger half-metallic gap. Finally, we discuss the stability of the surface. The positive formation energy in the bulk RbN indicates the surfaces unstable, and non-equilibrium growth techniques may be required for the realization of RbN thin films.     

Optimizing the Size of Micellar Nanoparticles for Efficient siRNA Delivery

Delivery of small interfering RNA (siRNA) by nanocarriers has shown promising therapeutic potential in cancer therapy. However, poor understanding of the correlation between the physicochemical properties of nanocarriers and their interactions with biological systems has significantly hindered its anticancer efficacy. Herein, in order to identify the optimal size of nanocarriers for siRNA delivery, different sized cationic micellar nanoparticles (MNPs) (40, 90, 130, and 180 nm) are developed that exhibit similar siRNA binding efficacies, shapes, surface charges, and surface chemistries (PEGylation) to ensure size is the only variable. Size‐dependent biological effects are carefully and comprehensively evaluated through both in vitro and in vivo experiments. Among these nanocarriers, the 90 nm MNPs show the optimal balance of prolonged circulation and cellular uptake by tumor cells, which result in the highest retention in tumor cells. In contrast, larger MNPs are rapidly cleared from the circulation and smaller MNPs are inefficiently taken up by tumor cells. Accordingly, 90 nm MNPs carrying polo‐like kinase 1 (Plk1)‐specific siRNA (siPlk1) show superior antitumor efficacy, indicating that 90 nm could either be the optimal size for systemic delivery of siRNA or close to it. Our findings provide valuable information for rationally designing nanocarriers for siRNA‐based cancer therapy in the future.     

Navigating Organo‐Lead Halide Perovskite Phase Space via Nucleation Kinetics toward a Deeper Understanding of Perovskite Phase Transformations and Structure–Property Relationships

Organo‐lead halide perovskite photovoltaics have developed faster than our understanding of the material itself. Using the vast body of work on perovskite processing created in just the past few years, it is possible to create a better picture of this material's complex phase‐transformation behavior. This concept paper summarizes and correlates the current understanding of structural intermediates, kinetic controls, and structure–property relationships of organo‐lead iodide perovskites. To this end, a new way of graphically relating information is developed, allowing the simultaneous mapping of schematic kinetic relationships between all currently prevailing perovskite deposition and growth techniques.     

富钛料在低浓度碱液中的水热反应研究

以富钛料为原料,研究其在Na OH溶液中水热反应的行为,应用Box-Behnken中心组合设计原理和响应面分析法研究了碱浓度、温度、反应时间等条件对Ti O2转化率的影响。结果表明:在碱浓度25%、温度186℃、反应时间4 h的条件下,得到的产物转化率最高,并在最优条件下验证了其转化率。采用扫描电子显微镜(SEM)及X-射线衍射仪(XRD)分析了反应产物的形貌及物相表征,表明在不同条件下得到了不同的反应产物,其形貌随着条件的不同逐渐发生改变。