Biopolymer passivation for high-performance perovskite solar cells by blade coating

Thin films of perovskite deposited from solution inevitably introduce large number of defects,which serve as recombination centers and are detrimental for solar cell performance.Although many small molecules and polymers have been delicately designed to migrate defects of perovskite films,exploiting credible passivation agents based on natural materials would offer an alternative approach.Here,an ecofriendly and cost-effective biomaterial,ploy-L-lysine(PLL),is identified to effectively passivate the defects of perovskite films prepared by blade-coating.It is found that incorporation of a small amount(2.5 mg mL^(-1))of PLL significantly boosts the performance of printed devices,yielding a high efficiency of 19.45% with an increase in open-circuit voltage by up to 100 mV.Density functional theory calculations combined with X-ray photoelectron spectroscopy reveal that the functional groups(-NH2,-COOH)of PLL effectively migrate the Pb-I antisite defects via Pb-N coordination and suppress the formation of metallic Pb in the blade-coated perovskite film.This work suggests a viable avenue to exploit passivation agents from natural materials for preparation of high-quality perovskite layers for optoelectronic applications.

Diamond Like Carbon Film Deposited on Porous Silicon as Passivation Coating

By depositing diamond like carbon (DLC) film with radio frequency plasma chemical vapor deposition (RFPCVD) method, a new surface passivation technique for photoluminescence porous silicon (PS) has been studied. The surface microstructure and photoelectric properties of both porous silicon and DLC coated PS have been analyzed by using AFM, FTIR and PL spectrotrieters. The results show the DLC film with dense and homogenous nanometer grains can be deposited on the PS used as passivation coating as it can terminate oxide reaction on the surface of the PS. Furthermore, certain ratio of hydrogen existed in the DLC film can be improved to form hydride species on the DLC/PS interface as the centers of the luminescence so that the DLC coating is of benefit not only to the passivation of the PS but also to the improvement of its luminescent intensity.

Electrolytic Passivation of Nitinol Shape Memory Alloy in Different Electrolytes

The corrosion behavior of the nitinol alloy was studied in various corrosion media of different Cl^- ion concentrations. The results demonstrate that the Cl^- ion concentration has significant influences on the corrosion behavior of the nitinol alloy. In order to enhance the corrosion resistance, protective films were generated on the surface of the nitinol alloy by means of the electrochemical passivation method, for which five different electrolytic solutions were investigated. The surface analysis indicates full growth of all samples passivated in the different electrolytic solutions with layers, however, showing different morphological features. Without any defects like micro-cracks and pores, the surface of the samples passivated in the molybdate solution turns out smoother and denser than those passivated in other solutions. It is shown that the electro-chemical passivation will reduce Ni content but increase Ti content in the surface, reaching the Mole ratio of Ti：Ni = 9.01：1 on the outermost surface. Potentiodynamic polarization test demonstrates that the samples electrochemically passivated in the molybdate solution present a significant increase in breakdown potential due to titanium enrichment on the outermost surface.

A PASSIVATION STUDY OF Ti-MODIFIED Fe—BASE ALLOY SYNTHESIZED BY MAGNETRON SPUTTERING TECHNIQUE

A set of fracture device was designed on the basis of traditional scratching-electrode technology and used to study the passivation process of two magnetron-sputtered stainless sleel coatings (amorphous and crystalline struture). The results of fracture tests in 3.5 % NaCl aqueous solution show that the amorphous alloy has a high bare surface reactivity and a high passive rate in comparison with the crystalline alloy. The effect of structure on corrosion resistance is also discussed. The excellent corrosion resistance of amorphous alloy is considered to be partly attributed to its great passivation ability.

Effect of pH and Dissolved Silicate on the Formation of Surface Passivation Layers for Reducing Pyrite Oxidation

Acid mine drainage (AMD)and toxic metal release generated by oxidation of sulphide minerals, particularly pyrite, in mine wastes,are a critical environmental issue worldwide.Currently, there are many options to diminish sulphide oxidation including barrier methods that isolate pyrite from oxygen or water, chemical additives and inhibition of iron-oxidizing bacteria. This study focuses on understanding the rolethatsilicate and pH conditions play in the formation and stabilisation ofpyrite surface passivation layers found in lab and field studies.The results from pyrite dissolution tests under various conditions showed that the pyrite oxidation rate has been reduced by up to 60% under neutral pH with additional soluble silicate. Solution speciation calculation predicted that crystalline goethite is formed in the experiment without silicate additionbutan amorphous iron hydroxide surface layer is stabilizedby the addition of the silicate, inhibiting goethite formation and continuing pyrite oxidation.This coherent, continuous amorphous layer has been verified in SEM.

Synergistic Effect of Mo, W, Mn and Cr on the Passivation Behavior of a Fe-Based Amorphous Alloy Coating

In this work,the electrochemical behaviors of SAM2X5 Fe-based amorphous alloy coating and hard chromium coating were comparatively studied in 3.5 wt% NaCl solution.In comparison with the hard chromium coating,the SAM2X5 coating exhibited a wider and stable passive region with lower passive current density in the potentiodynamic polarization and showed a considerably lower current density at different anodic potentials in the potentiostatic polarization.In order to understand the passivation mechanism of the Fe-based amorphous coating,the components of the passive films formed at various polarization potentials were examined by X-ray photoelectron spectroscopy.The synergistic effect of Mo,W,Mn and Cr in the passive films was systemically analyzed.It has been revealed that Mo and W facilitate the formation of compact and stable Cr2O3 passive film at lower potentials,and the substantial enrichment of Mn in the passive film enhances the passivation ability at relatively higher potentials.The deep understanding of the passivation characteristics in multicomponent alloy systems could provide a guide for the design of corrosion-resistant amorphous alloy coatings for engineering applications.

阿美项目管线内涂熔结环氧(FBE)粉末涂层的质量控制

本研究旨在分析阿美项目中熔结环氧(Fusion Bond Epoxy, FBE)粉末涂层的质量控制方法。首先通过对比阿美项目FBE内涂标准与国内标准,分析了FBE涂层质量控制的重要性和现有问题。接着以阿美项目为例,分析了FBE内涂工艺施工难点及质量控制要点。最后总结了该质量标准的优势和局限性,对国内外FBE内涂质量把控起到了重要的借鉴意义。

Efficient and Stable Perovskite Solar Cells and Modules Enabled by Tailoring Additive Distribution According to the Film Growth Dynamics

Gas quenching and vacuum quenching process are widely applied to accelerate solvent volatilization to induce nucleation of perovskites in blade-coating method.In this work,we found these two pre-crystallization processes lead to different order of crystallization dynamics within the perovskite thin film,resulting in the differences of additive distribution.We then tailor-designed an additive molecule named 1,3-bis(4-methoxyphenyl)thiourea to obtain films with fewer defects and holes at the buried interface,and prepared perovskite solar cells with a certified efficiency of 23.75%.Furthermore,this work also demonstrates an efficiency of 20.18%for the large-area perovskite solar module(PSM)with an aperture area of 60.84 cm^(2).The PSM possesses remarkable continuous operation stability for maximum power point tracking of T_(90)>1000 h in ambient air.

FBE与聚苯胺粉末共混涂层的防腐蚀性能

以苯胺为单体,过硫酸铵为氧化剂,采用超声波辅助的化学氧化法合成了聚苯胺,自制的聚苯胺与熔结环氧粉末(FBE)混合均匀后,用静电喷涂法在Q235钢上制备涂层。采用电化学阻抗谱(EIS)技术研究涂层在模拟海水中不同浸泡时期的防腐蚀性能。结果表明,聚苯胺粉末的加入提高了FBE涂层的防腐蚀性能,且加入量较少时,涂层的耐腐蚀性能随着聚苯胺含量的增加而增强,当质量分数达到5%时效果最好;在达到10%后,涂层中没有足够的粘结剂来填充聚苯胺之间的空间,使涂层多孔,防腐蚀性能变差。

钢质管道FBE防腐层抗划伤性能试验

针对环氧粉末防腐层施工中经常被划伤的现象 ,对其耐划伤性能进行了试验 ,分析了影响环氧粉末防腐层耐划伤性能的主要因素 ,并根据试验结果 ,计算得出了目前常用环氧粉末防腐层耐划伤性能的可靠厚度和使用可靠度 。

Rare earth passivation and corrosion resistance of zinc coated NdFeB magnets

Rare earth passivation was conducted on Zn coated NdFeB magnets by chemical reaction to enhance the corrosion resistance performance.Morphologies,micro structures and compositions of different passivated coatings were studied by X-ray diffraction,field emission scanning electron microscopy,and X-ray photoelectron spectroscopy,respectively.The corrosion behavior was evaluated by electrochemical measurement and neutral salt spray test.The results show that the rare earth passivation can enhance the corrosion resistance of Zn coated NdFeB magnets.When the concentration of cerium nitrate is 5 g/L,the passivated specimens can achieve the longest NSS time of 360 h,which is 144 h longer than that of the pristine Zn/NdFeB magnets.The passivation layer on the Zn coating surface contributes to the enhancement of the magnets’corrosion resistance.

Progress in Research on Vanadate-Based Coatings on Corrosion Resistance

Vanadate, usually used as the corrosion resistant inhibitor for the paint systems, is one of the substances that have been proposed as alternative to toxic chromate for the corrosion protection. In this paper, the possibility of vanadate passivating from its chemical properties was introduced firstly. Then, the progress and examples in research on vanadate conversion coatings on the corrosion resistance were summarized. And the substrates discussed here contained aluminum alloys, magnesium alloys and so on. Finally, the research tendency of vanadate-based coatings was discussed.

NON-CHROMATE CONVERSION COATING TREATMENT FOR MAGNESIUM ALLOY

A no pollution organic acid based conversion coating solution MIS. No.1 has been examined as to its suitability as possible replacement for chromate containing formulations on magnesium alloys. Investigations have concentrated on the formation of passive film from simple MIS. No.1 solution using immersion. The morphology of passivated surfaces was examined using scanning electron microscopy (SEM). The corrosion resistance of the passivated surfaces and the painted surface was assessed using electrochemical techniques as well as humidity and salt fog tests. It was concluded that the surface treatment magnesium alloy by MIS.No.1 solution is more effective than that by chromate coating treatment, and the MIS.No.1 coating is also suitable for painting's pretreatment.

海底管道三层聚烯烃防腐涂层系统FBE的质量控制

熔结环氧粉末(FBE)作为海管用三层聚烯烃防腐涂层的重要涂料,决定着防腐涂层的整体质量。本文主要从熔结环氧粉末的检验、涂覆、验收等方面来介绍海管防腐涂层的质量控制。通过工程案例介绍质量风险。通过熔结环氧粉末的材料特性与涂层施工工艺、涂层服役环境和熔结环氧粉末的技术要求,阐述了海管防腐层用熔结环氧粉末的质控要点。

油气采输行业对高温FBE涂层的新需求

传统熔结环氧粉末涂层(FBE)的玻璃化温度(Tg)通常<110℃,主要用于最高操作温度<95℃的管线。为满足全球对石油及天然气不断增加的需求,油气开采不断向深海领域延伸。但随着开采的延伸,采出的重原油具有更高的出口温度及高黏度特性,需要输送管道具有更高的操作温度(110~140℃),这对FBE防腐涂层提出了更高的要求。深海开采时管线操作温度较高,要求FBE具有更高的玻璃化温度以保障对管道的有效防腐。此外,油井管内防腐、高温蒸汽回注以及长输高温管线都需要FBE涂层具备更高的玻璃化温度以保证整体性能。本文阐述了各严酷应用环境中对高温FBE涂层的要求,同时总结了目前已商品化的高温FBE涂层,以期对国内环氧粉末企业拓展产品类型与应用领域提供借鉴。

化学预处理工艺在管道FBE涂层生产中的应用

管道防腐涂层的性能受钢管表面处理质量影响很大,为了提高表面处理质量,化学预处理工艺被引入防腐涂装施工中。化学预处理工艺中酸洗可提高钢管表面清洁程度,并形成多孔性的磷酸盐膜层,而钝化可将磷酸盐膜层孔隙中裸露的金属活性点位进行封闭,增强基材耐蚀性能。本研究中将酸洗及钝化工艺应用于FBE涂层生产中,对该工艺进行在线检验及离线涂层性能检测对比。结果显示,酸洗处理后钢管表面清洁程度明显提高,涂层性能得以改善;酸洗后增加钝化处理工艺,涂层性能进一步提高。

An electrochemical method for evaluating the resistance to cathodic disbondment of anti-corrosion coatings on buried pipelines

Methods for evaluating the resistance to cathodic disbondment （RCD） of anti-corrosion coatings on buried pipelines were reviewed. It is obvious that these traditional cathodic disbondment tests （CDT） have some disadvantages and the evaluated results are only simple figures and always rely on the subjective experience of the operator. A new electrochemical method for evaluating the RCD of coatings, that is, the potentiostatic evaluation method （PEM）, was developed and studied. During potentiostatic anodic polarization testing, the changes of stable polarization current of specimens before and after cathodic disbonding （CD） were measured, and the degree of cathodic disbondment of the coating was quantitatively evaluated, among which the equivalent cathodic disbonded distance AD was suggested as a parameter for evaluating the RCD. A series of testing parameters of the PEM were determined in these experiments.

Pitting corrosion behavior and corrosion protection performance of cold sprayed double layered noble barrier coating on magnesium-based alloy in chloride containing solutions

Nitrogen processed, cold sprayed commercially pure(CP)-Al coatings on Mg-based alloys mostly lack acceptable hardness, wear resistance and most importantly are highly susceptible to localized corrosion in chloride containing solutions. In this research, commercially pure α-Ti top coating having good pitting potential(~1293 mV_(SCE)), high microhardness(HV_(0.025): 263.03) and low wear rate was applied on a CP-Al coated Mg-based alloy using high pressure cold spray technology. Potentiodynamic polarization(PDP) curves indicated that the probability of transition from metastable pits to the stable pits for cold spayed(CS) Al coating is considerably higher compared to that with the CS Ti top coating(for Ti/Al/Mg system). In addition, CS Ti top coating was in the passivation region in most pH ranges even after 48 h immersion in 3.5 wt% NaCl solution. The stored energy in the CS Ti top coating(as a passive metal) was presumed to be responsible for the easy passivation. Immersion tests indicated no obvious pits formation on the intact CS Ti top coating surface and revealed effective corrosion protection performance of the CS double layered noble barrier coatings on Mg alloys in 3.5 wt% NaCl solution even after 264 h.

基材拉伸变形对FBE涂层性能的影响

地震、滑坡等地质灾害会造成埋地钢质管道变形。本工作对管道防腐蚀熔结环氧粉末涂层(FBE涂层)试件,在不同拉伸变形程度下的附着力、阴极剥离和冲击强度等性能进行了研究。结果表明,拉伸变形对FBE涂层的附着力和阴极剥离性能影响显著,随变形量增大,性能明显降低;在变形率不大于10%的条件下,FBE涂层的冲击强度仍能保持较好。

沙特阿美输油管道现场FBE内防腐补口技术

在沙特阿美标准体系下进行输油管道的现场FBE(Fusion-Bonded Epoxy)内防腐补口施工尚属首次。结合沙特拉斯坦努拉管道工程实际,介绍了沙特阿美FBE内防腐现场补口技术,阐述了FBE内防腐现场补口设备、防腐补伤材料、人员配置、环境要求、施工流程、工艺措施、安全要求、施工注意事项等内容。工程实践证明,在本项目管道环焊缝的FBE内防腐现场补口施工中,166道环焊缝仅有2道补口不合格,一次合格率达到了98.79%,施工进度达到5道/d,提高了施工效率,降低了施工成本。该项目的成功实施对今后在沙特进行类似工艺管道FBE内防腐现场补口施工有一定的指导意义。