铜氧化层上钒氧酞菁分子的吸附构型及组装结构

近年来,有机功能分子的调控因其在提高纳米光电器件内部载流子迁移率方面的突出贡献,已逐渐成为材料科学的热门领域之一.本文利用低温扫描隧道显微镜系统地研究了钒氧酞菁(VOPc)分子在干净Cu(110)和铜氧化层表面的吸附构型和组装结构.在Cu(110)表面,初始时VOPc分子孤立吸附且氧原子向上和向下的构型共存.而在CuO-(2×1)表面,VOPc分子在初始时形成扩展的分子链,随后组装为有序的分子膜,在分子膜中两种吸附构型仍然共存且随机排布.在Cu_(5)O_(6)-c(6×2)表面,初始时VOPc分子的两种构型共存且形成无序结构.在覆盖度接近一个单层时,结构有序的组装分子膜逐渐形成,此时主要采用氧原子向上的分子构型,因偶极相互作用,随后的分子层生长遵循两种分子构型交替堆垛.研究还发现当Cu(110)表面上两种氧化结构共存时,第2层分子更倾向于吸附在Cu_(5)O_(6)-c(6×2)表面担载的分子膜上,主要是由分子层间的偶极相互作用导致的.本研究表明金属表面的氧化层在改变分子吸附构型和组装结构方面的重要性,可能将影响电子器件制造中分子膜中的电荷输运过程.

Dispersion of copper oxide supported on γ-alumina and its sulfation properties

CuO/γ-Al2O3 catalysts were prepared by impregnation with different CuO loadings. The dispersion of CuO supported on γ-Al2O3 support was studied using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and temperature programmed reduction （TPR）. The dispersion threshold of CuO in γ-Al2O3 determined by X-ray quantitative analysis was 0.275 g/g, i.e., 0.275CuAl. Highly dispersed CuO or crystalline CuO would appear on the γ-Al2O3 support when CuO loading was below or more than its dispersion threshold. TPR experiments show that reduction peak temperature ranges of 0.1CuAl and pure CuO are 420-690 °C and 290-380 °C, respectively. 0.1CuAl is not easily reduced due to interaction between CuO and γ-Al2O3. 0.5CuAl shows a two-step reduction range during 210-300 °C and 410-730 °C, which confirms the existence of highly dispersed CuO and crystalline CuO. The sulfation experiments show the optimal CuO loading amount is far below its dispersion threshold, and copper oxide supported on γ-Al2O3 is in the form of submonolayer.

High temperature oxidation resistance and microstructure change of aluminized coating on copper substrate

The outermost coating with single phase Ni2Al3 was obtained on copper surface by electrodepositing nickel followed by slurry pack aluminizing at 800 °C for 12 h. The oxidation resistance and microstructure of the coating oxidized in ambient air at 1000 °C for 25-250 h were investigated using SEM, X-ray diffraction and optical microscope methods. The results show that the copper with single phase Ni2Al3 coating possesses the best high temperature oxidation resistance, and the mass gain of the coating is 1/15 that of pure copper and 1/2 that of nickel coating, respectively. The specimen surface after being oxidized for 25 h still comprises Ni2Al3 phase. However, when the time of oxidizing treatment increases to 50 h, the Ni Al phase is formed. It is also found that the Ni2Al3 phase completely turns into Ni Al phase after oxidizing treatment for 100 h and above. The Ni Al coating shows excellent high temperature oxidation resistance when oxidation time is 250 h.

A Novel Barrier to Copper Metallization by Implanting Nitrogen into SiO_2

The barrier to the copper diffusion is one of the key technologies in copper metallization. A novel barrier has been presented, which is a thin film of silicon oxynitride formed by implanting nitrogen into PECVD silicon dioxide. The method proved highly effective to block the copper diffusion after high frequency C V measurements at different BTS (Bias Thermal Stress) conditions and the XPS (X ray Photoelectron Spectroscopy) analysis. Furthermore, this method has the advantage of simplifying the damascene process of copper metallization, which has also been analyzed and discussed in detail.

Interfacial reactions of chalcopyrite in ammonia–ammonium chloride solution

The interfacial reactions of chalcopyrite in ammonia–ammonium chloride solution were investigated.The chalcopyrite surface was examined by scanning electron microscopy and X-ray photoelectron spectroscopy(XPS)techniques.It was found that interfacial passivation layers of chalcopyrite were formed from an iron oxide layer on top of a copper sulfide layer overlaying the bulk chalcopyrite,whereas CuFe1-xS2 or copper sulfides were formed via the preferential dissolution of Fe.The copper sulfide layer formed a new passivation layer,whereas the iron oxide layer peeled off spontaneously and partially from the chalcopyrite surface.The state of the copper sulfide layer was discussed after being deduced from the appearance of S2-,S22-,Sn2-,S0 and SO42-.A mechanism for the oxidation and passivation of chalcopyrite under different pH values and redox potentials was proposed.Accordingly,a model of the interfacial reaction on the chalcopyrite surface was constructed using a three-step reaction pathway,which demonstrated the formation and transformation of passivation layers under the present experimental conditions.

Selenium(Ⅵ) removal from caustic solution by synthetic Ca-Al-Cl layered double hydroxides

To extract selenium(Ⅵ)from the highly caustic leachate of copper anode slime,the Ca-Al-Cl layered double hydroxides(Ca-Al-Cl-LDHs)with a formula of Ca2 Al(OH)6 Cl·2 H2 O by three co-precipitation methods were synthesized.A plate-like morphology and hexagonal crystal structure with typical mineral phases and functional groups were identified by the FESEM,XRD,FTIR,BET and XPS analysis.The forward feeding sample exhibits the best adsorption capacity of Se(Ⅵ).The factor experiments then reveal a favorable adsorption process with low temperature,low NaOH concentration and high adsorbent dosage.Furthermore,the adsorption kinetics and isotherm parameters can be well described by the Langmuir isotherm and the pseudo-second-order models,respectively.Accordingly,the maximum adsorption amount of Se(Ⅵ)onto Ca-Al-Cl-LDHs reaches188.6 mg/g at 50 ℃.

Effect of sub-layer thickness on magnetic and giant magnetoresistance properties of Ni–Fe/Cu/Co/Cu multilayered nanowire arrays

Ni-Fe/Cu/Co/Cu multilayered nanowire arrays were electrodeposited into anodic aluminum oxide template by using dual-bath method at room temperature. Scanning electron microscopy and transmission electron microscopy were used to characterize the morphology and structure of the multilayered nanowire arrays. Vibrating sample magnetometer and physical property measurement system were used to measure their magnetic and giant magnetoresistance （GMR） properties. The effect of sub-layer thickness on the magnetic and GMR properties was investigated. The results indicate that magnetic properties of electmdeposited nanowires are not affected obviously by Cu layer thickness, while magnetic layers （Ni-Fe and Co layers） have significant influence. In addition, GMR ratio presents an oscillatory behavior as Cu layer thickness changes. The magnetic and GMR properties of the multilayered nanowire arrays are optimum at room temperature for the material structure of Ni-Fe （25 nm）/Cu （15 nm）/Co （25 nm）/Cu （15 nm） with 30 deposition cycles.

Tuning SnO_2 surface with CuO for soot particulate combustion: The effect of monolayer dispersion capacity on reaction performance

With the objective to investigate the structure-reactivity relationship of CuO/SnO2 and eventually design more applicable catalysts for soot combustion,catalysts with different CuO loadings have been prepared by impregnation method.By using X-ray diffraction and X-ray photoelectron spectroscopy extrapolation methods,it is disclosed that CuO disperses finely on the SnO2 support to form a monolayer with a capacity of 2.09 mmol 100 m^-2,which equals 4.8 wt%CuO loading.When the CuO loading is below the capacity,it is in a sub-monolayer state.However,when the loading is above the capacity,CuO micro-crystallites will be formed that coexist with the CuO monolayer.The soot combustion activity of the catalyst increases with the CuO loading until it reaches the monolayer dispersion capacity.A further increase in the CuO loading has no evident influence on the activity.Raman results have testified that with the addition of CuO onto the SnO2 support,a surface-active oxygen species can be formed,the amount of which also increases significantly with the increase in the CuO loading until it reaches the monolayer dispersion capacity.Increasing the CuO loading further has no evident impact on the amount of surface oxygen.Therefore,an apparent monolayer dispersion threshold effect is observed for soot combustion over CuO/SnO2 catalysts.It is concluded that the amount of surface-active oxygen sites is the major factor determining the activity of the catalyst.

High efficiency organic light-emitting diodes using CuO_x/Cu dual buffer layers

An organic light-emitting diode （OLED） device with high efficiency and brightness is fabricated by inserting CuOJCu dual inorganic buffer layers between indium-tin-oxide （ITO） and hole-transport layer （HTL）. The CuOx/Cu buffer layer limits the operating current density obviously, while the brightness and efficiency are both enhanced greatly. The highest brightness of the optimized device is achieved to be 14 000 cd/m2 at current efficiency of 3 cd/A and bias voltage of 15 V, which is about 50% higher than that of the compared device without CuOJCu buffer layer. The highest efficiency is achieved to be 5.9 cd/A at 11.6 V with 3 400 cd/m^2, which is almost twice as high as that of the compared device.

Highly efficient Cu_(2)ZnSn(S,Se)_(4) bifacial solar cell via a composition gradient strategy through the molecular ink

The use of transparent conducting oxide(TCO)as a substrate in Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)thin-film solar cells allows for advanced applications,such as bifacial,semitransparent,and tandem solar cells with the capability to increase power density generation.However,the efficiency of this kind of solar cell is still below 6% based on the low-cost solution process.In this work,we develop a composition gradient strategy and demonstrate a 6.82% efficient CZTSSe solar cell on F:SnO_(2)(FTO)substrate under the ambient condition.The composition gradient is realized by simply depositing the precursor inks with different Zn/Sn ratios.To verify that the high performance of the solar cell is attributed to the composition gradient strategy rather than the sole change of the Zn/Sn ratio,devices based on absorbers with varied Zn/Sn ratios are fabricated.Furthermore,the structure and surface morphology of the CZTSSe films with/without composition gradients are examined.The presence of elemental gradient through the depth of the CZTSSe films before and after annealing is confirmed by secondary ion mass spectroscopy analysis.It is found that the composition gradient enhances the crystallinity of the absorber,reduces the surface roughness as well as device parasitic losses,contributing to a higher fill factor,open-circuit voltage,and conversion efficiency.