Surface Reconstruction Engineering with Synergistic Effect of Mixed-Salt Passivation Treatment toward Efficient and Stable Perovskite Solar Cells

Surface passivation treatment is a widely used strategy to resolve trap-mediated nonradiative recombination toward high-efficiency metal-halide perovskite photovoltaics. However, a lack of passivation with mixture treatment has been investigated, as well as an in-depth understanding of its passivation mechanism. Here, a systematic study on a mixed-salt passivation strategy of formamidinium bromide (FABr) coupled with different F-substituted alkyl lengths of ammonium iodide is demonstrated. It is obtained better device performance with decreasing chain length of the F-substituted alkyl ammonium iodide in the presence of FABr. Moreover, they unraveled a synergistic passivation mechanism of the mixed-salt treatment through surface reconstruction engineering, where FABr dominates the reformation of the perovskite surface via reacting with the excess PbI₂. Meanwhile, ammonium iodide passivates the perovskite grain boundaries both on the surface and top perovskite bulk through penetration. This synergistic passivation engineer results in a high-quality perovskite surface with fewer defects and suppressed ion migration, leading to a champion efficiency of 23.5% with mixed-salt treatment. In addition, the introduction of the moisture resisted F-substituted groups presents a more hydrophobic perovskite surface, thus enabling the decorated devices with excellent long-term stability under a high humid atmosphere as well as operational conditions.     

Multiply Charged Conjugated Polyelectrolytes as a Multifunctional Interlayer for Efficient and Scalable Perovskite Solar Cells

A series of anionic conjugated polyelectrolytes (CPEs) is synthesized based on poly(fluorene-co-phenylene) by varying the side-chain ionic density from two to six per repeat units (MPS2-TMA, MPS4-TMA, and MPS6-TMA). The effect of MPS2, 4, 6-TMA as interlayers on top of a hole-extraction layer of poly(bis(4-phenyl)-2,4,6-trimethylphenylamine (PTAA) is investigated in inverted perovskite solar cells (PeSCs). Owing to the improved wettability of perovskites on hydrophobic PTAA with the CPEs, the PeSCs with CPE interlayers demonstrate a significantly enhanced device performance, with negligible device-to-device dependence relative to the reference PeSC without CPEs. By increasing the ionic density in the MPS-TMA interlayers, the wetting, interfacial defect passivation, and crystal growth of the perovskites are significantly improved without increasing the series resistance of the PeSCs. In particular, the open-circuit voltage increases from 1.06 V for the PeSC with MPS2-TMA to 1.11 V for the PeSC with MPS6-TMA. The trap densities of the PeSCs with MPS2,4,6-TMA are further analyzed using frequency-dependent capacitance measurements. Finally, a large-area (1 cm²) PeSC is successfully fabricated with MPS6-TMA, showing a power conversion efficiency of 18.38% with negligible hysteresis and a stable power output under light soaking for 60 s.     

Verhalten von Magnesiumlegierungen für Anwendungen im Fahrzeugbau bei mechanisch‐elektrochemischer Komplexbeanspruchung: Einfluss passivierender Deckschichten und Mechanismen der lokalen Schädigung

Behavior of Magnesium‐Alloys for Automotive Applications under Mechanical and Environmental Loading: Influence of Passivating Films and Mechanisms of Local Breakdown To assure an efficient design of components under cyclic loading, all available data concerning fatigue have to be observed. Therefore the influences of manufacturing on the material condition, the mechanical loads and environmental effects have to be analysed. Magnesium‐alloys are of special interest for lightweight applications because of their excellent strength‐density ratio. The corrosion resistance of magnesium‐alloys depends on the same factors that are critical to other metals. The alloys have a good stability to atmospheric exposure and a good resistance to attack by alkali, chromic and hydrofluoric acids. However, because of the electrochemical activity of magnesium, the relative importance of some factors is greatly amplified. The nature and composition of passive films formed on magnesium‐alloys depend on the prevailing conditions, viz. alloy‐composition, passivation potential, pH, electrolyte composition and temperature. Passive films may be damaged by local breakdown. Because of this, magnesium‐alloys suffer a degradation of their properties when exposed to an aqueous environment. The main topic of the present investigations is the verification of mechanisms of the local breakdown of the protecting film. At least two mechanisms are possible for this localization: mechanical breakdown by slip steps and electrochemical breakdown (for e.g. by the effects of chloride ions). Corrosion and passivation of different high purity alloys have been studied in different solutions (neutral, alkaline with specific anions and cations) using electrochemical techniques. The diecasted alloys were tested as produced and machined. The results clarified that depending on alloy/material and surface condition/corrosion environment different mechanisms for electrochemical breakdown of the protecting films are possible. Hence fatigue life under environmental loading is influenced by surface and testing conditions.     

无钴黑色陶瓷颜料中铬含量测定的新方法

本文以盐酸羟胺作还原剂,研究了三价铬与二甲酚橙的显色反应,结果发现Cr3 在0～80滋g/50ml范围内,其吸光度与Cr3 含量成正比相关,用于无钴黑色陶瓷颜料中铬含量的测定,作出了回归方程,且进行了显著性检验,获得了理想的结果。     

生物除铬(VI)效果及机理探讨

以特定污泥挂膜的自制厌氧生物滤床系统具有良好的去铬(VI)能力。恒流泵最佳流量为47mL/min,外加碳源使废水COD约140mg/L,铬(VI)的浓度由60mg/L左右降到0.5mg/L以下(一级排放标准),需要4h,而对照组(未加碳源)需要14h。铬(VI)浓度由64.66mg/L提高到75.53mg/L时,对系统负面影响甚微,提高到95.47mg/L时,系统出水达标所需时间延长到7.5h。添加微量金属离子与未添加微量金属离子的情况相比,处理效率提高21.26%。分析试验表明:铬(VI)的去除途径可能是由生物还原作用将六价铬还原为三价铬,形成氢氧化铬沉积于微生物表面。     

催化裂化汽油脱硫助剂TS-01的工业试验

中国石油化工股份有限公司九江分公司在I套催化裂化装置进行了TS—0l催化裂化汽油脱硫双功能助剂的工业应用。结果表明：TS—0l剂对催化裂化汽油有较好的脱硫效果。当TS—0l剂注入原料中的量为70μg／g时，对催化裂化汽油的硫脱除率约为20％；注入量为120μg／g时，硫脱除率可达到25％-30％。汽油中脱除的硫主要以硫化氢形态转移至于气、液化气中。TS—01剂对产品分布及产品其它质量无明显影响，该剂亦有良好的金属钝化效果。     

无铬钝化技术研究的进展

评述了文献报道和各种不同的无铬钝化工艺的特点及其发展现状。目前还没有一种无铬钝化工艺能够完全代替铬酸盐钝化工艺，某些无铬钝化工艺在某些方面已经与铬酸盐钝化相当，但其市场前景、应用范围及用户环保效果还需要进一步研究。     

热钾碱法脱碳的缓蚀及钒化工艺技术改进的试验研究

介绍了热钾碱法脱碳钒化工艺技术改进的试验过程，开发了原始开车钒化，在一定条件下取消钒含量控制，实现了运行中不加钒、中修后开车不钒化的新工艺技术。本技术已通过化工部鉴定，处于国内领先水平，并具有可观的经济效益。     

Tannins/melamine–urea–formaldehyde (MUF) resins substitution of chrome in leather and its characterization by thermomechanical analysis

A new sulfonated melamine–urea–formaldehyde (MUF) resin of relatively low melamine content, prepared according to a sequential formulation, has been shown to be highly effective when coupled with different natural vegetable tannins to produce leather with the same good characteristics of leather prepared with chrome salts. In particular, the antishrinkage effectiveness of the leather prepared according to the new approach is comparable to that obtained with chrome tanned leathers. The comparison of the traditional leather shrinkage temperatures test method with a new thermomechanical analysis (TMA) test method in tension yields thermograms presenting three major modulus of elasticity (MOE) peaks. These are closely connected to molecular level phenomena determining the shrinkage temperature of leather. The three determining parameters appear to be as follows: (1) The average value of the temperatures at which the three MOE peaks occur: the higher the value of this average, the lower is the shrinkage of leather. (2) The average of maximum MOE values of the TMA peaks: the higher this average is, the better is the leather in regard to antishrinkage effectiveness. This means the leather maximum MOE at each peak is a measure of the resistance to the contraction force induced by heat. (3) The relative intensity of the first TMA peak in relation to the second: the higher the value of the MOE for the first TMA peak is in relation to the second peak, the lower the leather shrinkage appears to be. However, it has not been possible to better define or quantify this latter effect. This new TMA test method in tension has also yielded a mathematical relationship correlating the thermogram peak temperatures and MOE averages with the traditional shrinkage temperature to a high degree of confidence. A previous TMA test method, in compression, has proven to yield more problematic and finally not very reliable results when one needs to apply it to a wide variety of different cases. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1889–1903, 2003     

Very low surface recombination velocities on p-type silicon wafers passivated with a dielectric with fixed negative charge

Surface recombination velocities as low as 10 cm/s have been obtained by treated atomic layer deposition (ALD) of Al₂O₃ layers on p-type CZ silicon wafers. Low surface recombination is achieved by means of field induced surface passivation due to a high density of negative charges stored at the interface. In comparison to a diffused back surface field, an external field source allows for higher band bending, that is, a better performance. While this process yields state of the art results, it is not suited for large-scale production. Preliminary results on an industrially viable, alternative process based on a pseudo-binary system containing Al₂O₃ are presented, too. With this process, surface recombination velocities of 500–1000 cm/s have been attained on mc-Si wafers.