bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Potentiometric Biochemical Sensors for Diagnostic Applications
Authors: Vogel Eric M
Published: February 2020

The detection of chemical and biological species is critical for applications in healthcare, environmental monitoring, food safety and drug screening. Potentiometric biochemical sensors rely on the specific adsorption of charged analytes that changes the potential of the functionalized sensor surface. The change in surface potential can be measured using a field-effect-transistor enabling low-cost fabrication, and easy integration with portable readout electronics. Over the past several decades, these sensors have been demonstrated to detect pH changes, metal ions, DNA, biomarkers, proteins, and enzymes. Although many biosensing experiments have been reported, many of the results are not well understood and several key challenges are still limiting their widespread application. The ability to stabilize and control the attachment of cells on the sensor surface is critical. Therefore, the reliability and reproducibility of self-assembled-monolayers will be presented. The experimental response from a variety of sensor surfaces (oxides or metals) and transducers (conventional silicon, nanowire, extended gate, or graphene transistors) will be presented. The results show that the choice of the active interface in contact with the electrolyte determines the sensor response and selectivity (the signal) independent of the transducer. The choice of the readout transducer mainly influences the noise limit, and, hence, the signal-to-noise ratio. Models for diffusion, attachment, and electrical response of these sensors will be described that demonstrates good agreement to experimental data. Finally, the application of these devices in the animal health sector for the diagnosis of bovine respiratory disease, which is a major cause of calf death, will also be presented.
(Invited) Switchable White Graphene: Electrochemistry of the Boron Nitride Nanomesh
Authors: Mertens Stijn F. L.
Published: February 2020

On Rh(111), a monolayer of hexagonal boron nitride (h-BN, isoelectronic with graphene) forms a so-called nanomesh superstructure [1], characterized by a 3.2-nm lattice constant and strong electronic corrugation, which can be used for trapping atoms and molecules [2,3]. Here, we show that hydrogen underpotential deposition (H upd) is easier on h-BN/Rh(111) than on the naked substrate [4], and leads to submonolayer quantities of hydrogen intercalated between the h-BN overlayer and Rh(111), as demonstrated by electrolyte-to-vacuum transfer experiments and thermal desorption spectroscopy. In situ STM measurements reveal that the intercalation lifts the corrugation of the nanomesh, and that this process is fully reversible under potential control. Copper upd is used to quantify the defect density in the nanomesh, and to increase the understanding of the electrochemical window where the nanomesh is stable. By measuring dynamic contact angles of an electrolyte drop (see Figure), we show that the microscopic change within the 2-dimensional material leads to a macroscopic effect related to a 10% change in adsorption energy [4]. The static friction on the other hand, which can be extracted by extending the Young equation for non-equilibrium effects, remains unchanged for the surface in the two states.

[1] M. Corso, W. Auwärter, M. Muntwiler, A. Tamai, T. Greber, J. Osterwalder, Science 303 (2004) 217–220.

[2] S. Berner, M. Corso, R. Widmer, O. Groening, R. Laskowski, et al. Angew. Chem., Int. Ed. 46 (2007) 5115–5119.

[3] H. Dil, J. Lobo-Checa, R. Laskowski, P. Blaha, S. Berner, J. Osterwalder, T. Greber, Science 319 (2008) 1824–1826.

[4] S.F.L. Mertens, A. Hemmi, S. Muff, O. Gröning, S. De Feyter, J. Osterwalder, T. Greber, Nature 534 (2016) 676–679.

Figure 1
Luminescent Si-Based Nanostructures Fabricated By Plasma Enhanced Chemical Vapour Deposition Techniques
Authors: Khatami Zahra , Miller Jeremy William , Wojcik Jacek , Mascher Peter
Published: February 2020

In order for Si-based materials to be used in solid-state lighting (SSL) schemes it is necessary to have precise control of the emission from these materials. This can be accomplished through the use of rare earth dopants such as Ce, Tb, and Eu to obtain blue, green, and red emissions, respectively. This talk will focus on the luminescence of various silicon-based nanostructures (such as silicon oxides, nitrides, and carbides) and the effect of rare earth doping of such systems. We have demonstrated very high, optically active concentrations of the rare earths by using in-situ doping processes, using electron cyclotron resonance chemical vapour deposition (ECR-CVD) or inductively coupled plasma (ICP) CVD as low thermal budget processes for film deposition. I will describe the salient features of the deposition systems and correlate important process parameters with the observed luminescence. Finally, I will discuss some of the challenges in developing electrically driven lighting cells suitable for SSL and in particular, the development of white light emitters from rare earth doped Si-based materials.
Nanoscale Spin-Transfer Torque MRAM Etching Using Various Gases
Authors: Yang Kyung Chae , Park Sung Woo , Lee Ho Seok , Yeom Geun Young
Published: February 2020

As the volatile dynamic random access memory (DRAM) device faces a physical limitation, new memory devices are actively investigated to solve this problem. Among them, spin transfer torque magnetic random access memory (STT-MRAM) has received a lot of attention because of its very high speed of device, endurance, low power consumption of device, and high density memory cell in addition to the non-volatility of information. Especially, the MTJ memory elements which consist of CoxFeyBz/MgO/CoxFeyBz multilayer structure are the critical building blocks for high density magnetic random access memory with high tunneling magnetoresistance(TMR). However, the dry etching of MTJ stack with sub 70 nm is a challenging step in the fabrication of STT-MRAM. The etching of nanoscale MTJ induces oxidation in magnetic layer, pattern degradation and damage or sidewall redeposition at patterned MTJ sidewall especially.

In this study, for successful etching of MTJ and MTJ related materials, RIB (reactive ion beam) etching using NF3, CH3OH, and CO/NH3 gas mixture and ICP etching using Ar, He, CO/NH3 and so on were conducted. Etch characteristics of magnetic tunnel junction (MTJ) stacks masked with W were investigated precisely using field emission scanning electron microscopy (FE-SEM) and TEM (Transmission electron microscopy). Simulation of MTJ material and hardmask material was conducted with SRIM simulation to observe tendency with etch process of blank unit thin film samples. In addition, the magnetic hysteresis curves were analyzed by a vibrating sample magnetometer (VSM). The results showed that, among the various gas combinations, the use of He gas improved etch selectivity of MTJ materials over W and also improved the etch profile of MTJ features. Also the He etch gas could be beneficial in reducing damage. The detailed etch mechanism and results on the etching of MTJ materials will be presented.
(Invited) Plasma Electrochemical Synthesis of Nanomaterials
Authors: Chen Qiang
Published: February 2020

When discharge plasma is in contact with liquid, the plasma-liquid interface provides a powerful reaction zone for many physical and chemical processes induced by the plasma-liquid interactions. A great number of applications take advantage of this highly active zone of plasma-liquid interface, such as plasma medicine, element analysis, and nanomaterials formation. The nanomaterials formation from plasma-liquid interactions is some kind of a modified electrochemical deposition, called plasma electrochemical method, but it is not the same to the latter, and it has some distinct characteristics, for instance, a gaseous plasma electrode instead of a solid electrode. Since there are several advantages for the plasma-liquid based nanomaterials formation, such as high synthesis speed, simplicity in device, compared to a solution-based one, nanomaterials synthesis from plasma-liquid interactions attracts much attention recently. In this talk, we give a review of the plasma electrochemical synthesis of nanomaterials. Additionally, we survey the basic processes in the plasma-liquid interface and the bulk solution, the role of these processes play in nanomaterials formation, and the current state of plasma electrochemical synthesis of nanomaterials. The technical challenges to future research on plasma electrochemical synthesis of nanomaterials are also discussed.

The work was partially supported by National Natural Science Foundation of China (Grant No.: 11405144), and the Fundamental Research Funds for the Central Universities (Grant No: 20720150022).
(Invited) Engineering of Nanostructures Using Microplasmas for Catalysis and Biosensing
Authors: Chiang Wei-Hung
Published: February 2020

Microplasmas are a special class of electrical discharges formed in geometries where at least one dimension is less than 1 mm. As a result of their unique scaling, microplasmas operate stably at atmospheric pressure and contain large concentrations of energetic electrons (1-10 eV). These properties are attractive for a range of nanomaterials synthesis and nanostructure engineering [1-3]. Recently the development of carbon nanomaterials such as carbon nanotubes (CNTs) and graphene has been leading us to an exciting direction for both fundamental science and commercial applications because of their exceptional properties. While researchers have achieved significant progress in CNT synthesis, precise control of structure including diameter, wall number, and chirality remains a critical technological challenge due to the unclear role of the catalyst in controlling the CNT structure. Surface enhance Raman scattering (SERS) is a promising technology for various applications including plasmonic devices, photo energy generation and conversion, biomedical detection and chemical sensing. However, this conventional approach to fabricate SERS-active materials is usually time-consuming and laborious. In this presentation, I will discuss these topics in detail, highlighting the advantages of microplasma-based systems for the synthesis of well-defined nanomaterials. These experiments will aid in the rational design and fabrication of nanoparticle alloys for selective growth of CNT structures and may also have significant impact in other catalytic applications including nanowire growth, gas conversion, and fuel cells. Moreover I will present a facile synthesis of silver (Ag) nanoparticles (NPs)/graphene composites using a unique atmospheric-pressure microplasma-assisted electrochemistry. The systematic micro Raman study indicates that the AgNP/graphene composites show superior SERS performance with low detection concentration of 10-
10 M of R6G and high enhance factor (EF) about 1×109.

Reference:

[1] W-H. Chiang and R. M. Sankaran, Appl. Phys. Lett. 91, 121503 (2007)

[2] W-H. Chiang and R. M. Sankaran, Adv. Mater. 20, 4857 (2008)

[3] W-H. Chiang and R. M. Sankaran, Nature Mater. 8, 882 (2009)
(Invited) Microplasma-Deposited Ni-Fe and Co Oxides for Oer and Supercapacitors
Authors: Pebley Andrew , Mackie Katherine , Gordon Michael
Published: February 2020

Microplasma-based spray deposition was used to create high surface area Ni-Fe and Co oxide nanostructures on a variety of substrates (e.g., ITO, lithographic patterns, fibers) for electrocatalysis and supercapacitor applications. NiO, Fe-doped (rocksalt) NiO, NiFe2O4, and CoxOy films were deposited at 10-100 torr using a flow through, hollow cathode supersonic jet plasma with organometallic precursors. The resulting films were subsequently evaluated for their oxygen evolution reaction (OER) activity and potential use as Faradaic supercapacitors. OER overpotentials were compared for the various Ni-Fe oxides, and Fe-doping of the rocksalt NiO structure at the few % level was seen to lower overpotentials to ~0.3 V at 10 mA/cm2, which compare well with those obtained with more expensive Ru and Ir oxides. Turnover frequency increased to 0.5 1/s with Fe loading at 350 mV overpotential; morphology and surface composition (SEM, XPS) before and after electrochemical testing showed slight restructuring of the catalyst surface and an increase in Ni(OH)2. Electrochemical activity and overpotentials were also very stable, as evidenced by extended chronoamperometry and CV testing. For supercapacitor applications, NiO and CoxOy were directly spray deposited on carbon cloth at room temperature; double layer and Faradaic pseudo-capacitance ranged from 100-300 F/g at 10 mV/s scan rates, with faster plasma jet rastering rates yielding higher surface area and effective capacitance. The talk will highlight the microplasma deposition method and discuss the aforementioned electrochemical results in detail.
(Invited) Enhanced Cycle Capacity of Lithium Ion Batteries with Nanocomposite Si Anodes Produced by Rapid Co-Condensation in Plasma Spray PVD
Authors: Fukada Kohei , Ohta Ryoshi , Kambara Makoto
Published: February 2020

Silicon (Si) is the promising candidate of anode for the next generation high-density lithium-ion batteries (LiB) owing to its 10 times greater theoretical capacities than the conventional carbonous material. This material however needs to be structured at nano-to-micron length scale to cope with inevitable volume change up to 400% during (de)lithiation reaction that leads eventually to fracture of the material and to a significant capacity drop in short cycles. Among various approaches for structuring proposed, battery industries are seeking for techniques with which high throughput production at reasonable cost is anticipated. In this respect, plasma spray physical vapor deposition (PS-PVD) can be a strong candidate. In fact, 20-40 nm nanoparticles (NP) are produced from metallurgical grade Si powders which is several dollars per kilogram and these particles used as anode of the battery have exhibited an improved capacity retention at longer battery cycles. Further improvement in cycle capacity has been observed with nanocomposite Si:Ni anode, in which NiSi2 are epitaxially attached on Si-NP through heterogeneous nucleation during co-condensation of Si-Ni vapors. Uniqueness of this anode is that crystalline Si (c-Si) anode remains even after 50th cycle while c-Si conventionally experiences the structural change to amorphous as a result of (de)lithiation. The electric resistance associated with anode is also found to reduce with Si:Ni-NP. These suggest that the epitaxial NiSi2 contributes mechanically and electrochemically to suppress the capacity decay during cycles. The detailed effect of additives will also be discussed in the presentation. This work was partly supported by Grant-in-Aid for Scientific Research (B) 15H04152 of Japan.

References: [1] Graetz, J. et al., Electrochem. Solid-State Lett. 2003,6 (9), A194-A197. [2] Liu, X.H. et al., ACS Nano 2012, 6 (2), 1522-1531. [3] Magasinski, A. et al., Nature Mater. 2010, 9, 353-358. [4] Kim, H. et al., Nano Lett. 2008, 8 (11), 3688-3691. [5] Kambara, M. et al., J. Appl. Phys. 2014, 115 (14), 143302.
(Invited) An Aqueous Rechargeable Desalination System
Authors: Yang Hui Ying
Published: February 2020

In this work, we present a new concept of aquous flow battery deionization (FBDI) system based on dual-ions electrochemistry, which consists of BiOCl as chloride-capture anode, sodium manganese oxide (Na0.44MnO2) as sodium-capture cathode. It utilizes a redox reaction to individually absorb chloride ion at anode and sodium ion at cathode at the same time. When charged, the two ions are released to flow sodium chloride electrolyte solution. Upon discharge, the chloride ion was extracted into the anode from flow NaCl solution while sodium ion was electrochemically captured into the cathode. The novel battery deionization delivers a stable and reversible salt absorption/desorption capacity of 68.5 mg g-1 with ~100% columbic efficiency when operated at a current density 100 mA g-1, which makes over twice salt absorption of the previous reported best performance (31.2 mg g-1) obtained by a hybrid capacitive deionization system. The “ion/electron transfer efficiency” as a new concept was proposed to replace the “charge efficiency”, since the salt was removed during the discharge process, which is the first time to report thus a phenomenon. The ion/electron transfer efficiency is up to 0.977 during charge-desorption process and 0.958 during discharge-absorption process. Owing to salt removal during discharge, the current system is called “desalination generator”. The current study will supply a new view of desalination and flow battery system.
(Invited) Plasma Based Synthesis of Conductive Polymers: Experimental Results and Some Remarks about General Strategies for Plasma Based Polymerization Processes
Authors: Berndt Johannes , Pattyn Cedric , Hussain Shahzad , Kovacevic Eva
Published: February 2020

Conductive polymers belong certainly to the most promising materials in current research. They have a high potential for a great variety of different applications as for example for super capacitors, antistatic coatings for electronic packaging, electrodes for organic LEDs or for novel types of sensors [1]. This contribution deals with the plasma based synthesis of intrinsically conductive polymers which can be produced either in the form of thin films or as nanoaparticles and nanoparticle deposits. Despite the successful application of plasma processes for the deposition of thin films in general (in particular on an industrial scale) the plasma based synthesis of conductive polymers still remains a great challenge in particular with respect to the avoidance of excessive cross linking reactions.

This paper will mainly focus on polymerization processes in low temperature plasmas containing aniline. Aniline (C6H7N, prototypical aromatic amine) is a monomer used in industry for production of for example polyurethane precursors, but also in the production of polyaniline. Polyaniline was one of the first conducting polymers used in practice (e.g. as an antistatic coating material) in particular due to its high stability also in aggressive chemical environments due to its unique complex properties and due it slow manufacturing cost. Recent works showed that PANI nanostructures and in particular PANI nanoparticles are also promising materials for microwave absorption [3].

This contribution will discuss experiments concerning the deposition of thin films and the production of nanoparticles in a capacitively coupled (low temperature) plasma operated in mixtures of noble gases and aniline. The experiments comprise the analysis of the plasma (plasma mass spectroscopy, in-situ multi pass FTIR spectroscopy, Laser light scattering, microwave interferometry) and the analysis of the obtained material (NEXAFS, XPS, FTIR, SEM). The discussion will be completed by some general remarks about the control of plasma based polymerisation processes in particular by using pulsed plasmas.

Acknowledgments: The financial support of the European Commission under the FP7 Fuel Cells and Hydrogen Joint Technology Initiative grant agreement FP7-2012-JTI-FCH-325327 for the SMARTCat project is gratefully acknowledged, as well as support obtained by French Region Centre project APR IR Capt’Eau.

[1] T.K. Das and S.Prusty, Polymer-Plastics Technology and Engineering, 51: 1487–1500, 2012

[2] M. Atesa, T. Karazehir and A. Sezai Sarac, Current Physical Chemistry, 2012, 2, 224-240

[3] P. Zhang, X.Han, L. Kang, R. Qiang, W. Liu and Y. Du, RSC Advances, 2013, 3, 12694
Poly-Si Planarization by ICP Plasma Etch at FinFET Technology
Authors: Wang Yan , Han Qiuhua , Zhang Haiyang
Published: February 2020

Abstract:

The fin field effect transistors (FinFET) have been extensively explored for many years and recently mass production have been realized for its superior properties in solving short channel effects and size-down requirements. [1]

In FinFET technology node, the topography started to turn worse due to the introduction of the three-dimensional (3D) fin structures. The control became one of the most important issues in FEoL. In poly-gate loop, the lithography window and poly silicon etch profile will be limited by the surface topography and thus affect the device performance as well as the yield improvement. To improve the poly-silicon topography after the CMP process becomes very important.

In this paper, we report the poly-silicon planarization with the introduction of the matrix-temperature controller, named as Hydra, which is equipped in one commercial inductive coupled plasma (ICP) etch tool. The 3sigma of poly-silicon thickness within improved 80% and the uniformity is very close to current planar technology node, as shown in Figure 1. The temperature dependence is 21.7A/℃. The planarization results show better performance than gas cluster ion beam (GCIB) method as reported. [2]

For more common use, an advanced process control is also proposed to overcome the difference of incoming after CMP process. The CMP process always shows a major radical thickness map, which can be compensated by tuning radical etch rate map by changing process parameters. The Hydra based etch planarization technology can also be extend to other process as ILD etch back with suitable etch process. This technology will be very power in the future 3D transistors for planarization.

This work was partially sponsored by Program of Shanghai Technology Chief Scientist (B type). The authors would like to thank Mr. Kui Wang, Mr. Jiangang Liu, and Dr. Yushan Chi from Lam research for the support of constructive discussion.

Reference:

[1] C. Auth et al., “A 22 nm high performance and low-power CMOS technology featuring fully-depleted tri-gate transistors, self-aligned contacts and high density MIM capacitors,” in VLSI Symp. Tech. Dig., pp. 131–132, 2012,

[2] T. Kagalwala et al., “Integrated metrology's role in Gas Cluster Ion Beam etch”, 26th Annual SEMI Advanced Semiconductor Manufacturing Conference (ASMC), pp. 72-77, 2015

Figure 1
Novel Biomedical Electrosurgical Device Containing Nanostructured Surface Functionalization for Minimally Invasive Surgery: Characterization and Histological Evaluation in Rat
Authors: Cheng Han-Yi , Ou Keng-Liang , Chen Shyuan-Yow
Published: February 2020

The objective of the present study was to investigate the thermal injury and tissue sticking in the liver after a minimally invasive electrosurgery with a chromium nitride (CrN) surface modifications. The surface morphologies and the hydrophobic properties of CrN thin films were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM) and contact angle goniometer. Three-dimensional (3D) liver models were reconstructed using magnetic resonance imaging to simulate the electrosurgical procedure. In animal model, needle type monopolar electrosurgery equipped with CrN thin films were used to create lesions in the liver of adult rats. Animals were sacrificed for evaluations at 0, 1, 2, and 4 weeks postoperatively. Data indicated that the temperature decreased significantly when minimally electrosurgery with nanostructured CrN thin films were used, and that it continued to decrease with increasing film thickness. In an animal model, thermography revealed that the surgical temperature was significantly lower in the minimally invasive electrosurgery with CrN thin film compared to untreated electrosurgery. In addition, adherence analysis showed that the smallest amount adherence tissue on the CrN electrode. Moreover, CrN electrosurgery created a relatively small thermal injury area and lateral thermal effect. The present study reveals that the novel nanostructured thin film on electrode substrates is an effective means of improving the performance of reducing excessive thermal injury, decreasing adherence tissue, and uniformly distributing temperature in the liver. However, further tests in the clinical trial must be evaluated to confirm the effect and safety of promising findings in the electrosurgery.
Evaluation of Key Factors for Preparing High Brightness Surfaces of Aluminum Films Electrodeposited from AlCl3-1-Ethyl-3-Methylimidazolium Chloride-Organic Additive Baths
Authors: Matsumoto Futoshi , Tanabe Toyokazu , Gunji Takao , Kaneko Shingo , Ohsaka Takeo
Published: February 2020

The effects of additives, such as 4-pyridinecarboxylic acid hydrazide (4-PCAH) and its analogs, and organic solvents, such as toluene, benzene and xylene, on the brightness of aluminum (Al) prepared using constant-current deposition from an ionic liquid of ethyl-3-methylimidazolium chloride (EMIC)-aluminum chloride (AlCl3) were investigated by light spectroscopy, scanning electron microscopy (SEM), reflectivity tests, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy. In order for the deposited Al films to exhibit high brightness, a combined use of 4-PCAH and toluene is effective. Moreover, the relationship between the brightness (i.e., reflectance) of the prepared Al films and the molecular structure of a variety of additives was clarified. Both a pyridine ring and an acetyl hydrazine group are necessary for constituting an effective additive. The structural isomers of a given additive bring about different surface brightness, e.g., for PCAHs the reflectance at 450 nm is in the order of para-isomer > meta-isomer > ortho-isomer. It was considered that in 4-PCAH electron-withdrawing acetyl hydrazine group is bounded to the pyridine ring, and consequently the electron density around the nitrogen atom in the pyridine ring is decreased, which is conducive to the adsorption of 4-PCAH on the cathode of deposited Al films. In addition, the reflectance was found to increase with decreasing the crystalline domain size of Al deposits and with increasing the reaction resistance for Al electrodeposition. The reaction mechanism of Al electrodeposition from the present ionic liquid media containing various additives is also discussed briefly.
Electrodeposition of Purified Aluminum Coatings from AlCl3-Dimethylsulfone(DMSO2) Electrolytes with Isopropylamine Hydrochloride
Authors: Kim Sangjae , Kumeno Shota , Kuroda Kensuke , Okido Masazumi
Published: February 2020

Aluminum (Al) have played an important role in the recent advance of civilization and as a basic material for industry, construction, and agriculture. Because of its glossy appearance, low weight, and good mechanical properties, Al has been widely used in the information technology and electronics industries, e.g., smart phones, notebooks, netbooks, etc.

However, Al requires surface treatment to improve corrosion resistance, durability, wear resistance, abrasion resistance. Al coatings have been electrodeposited from AlCl3 - dimethylsulfone (DMSO2) electrolytes at 403K. The coatings usually contained trace amounts of sulfur (S) due to DMSO2 and chlorine (Cl) due to AlCl4
- as impurities. Since these impurities make the coatings hard and brittle, and moreover may adversely affect the corrosion- and oxidation resistances of the Al coatings, it would be desirable to decrease their contents in the Al coatings. Examination of the Al coatings electrodeposited from the electrolytes with the addition of various amounts of isopropylamine hydrochloride (IPA) revealed that the S and Cl contents of the Al coatings decreased with increasing concentration of IPA in the electrolyte. The addition of IPA also brought about changes in the surface morphology and crystal orientation of the Al coatings. Preferential adsorption of IPA on the surface of the Al deposit was inferred to be a cause of the exclusion of S and Cl from the Al coating. As a result of the decrease in S and Cl contents, the Al coatings were softened.

Cyclic voltammgram shows 23 mol % AlCl3 / DMSO2 electrolytes contain from 0 to 0.4mmol IPA with respect to 10 M DMSO2. Most of the cycles of precipitation and dissolution of Al was occurs at the potential of - 0.5V. The addition of IPA, lead to decreasing of the flowing current and produce smooth stable films. The higher current density was observed at 0.1mmol IPA among using additives. On the other hand, the lower and stable cathodic current 0.2mmol produces smooth film.

S and Cl contents plots the Al coatings determined by EDX against the IPA content in the electrolyte. While the Al coatings from the electrolyte without IPA contained 2.1 mass % S and 1.4 mass% Cl, both the contents decreased with increasing content of IPA in the electrolyte. The decrease leveled off when the amount of IPA was 0.2mmol, at which point the S and Cl contents were below 1 mass %.

SEM images shows the surface of these samples. It can be seen that the film formed in the solution without additive is many cracks are observed. On the other hand, the film fotmed on the solution with the using 0.2mmol IPA contains no crack.

Figure 1
Effect of the Use of Pulse Plating Techniques in Electrodeposited Sn-Cucoatings for Pb-Free, Environmentally-Friendly Applications
Authors: Wu Liang , Cobley Andrew J
Published: February 2020

The electrodeposition of lead containing alloys have found many industrial applications including electronics and other applications. However, lead is very harmful to health and the environment and the Restriction of Hazardous Substances Directive (RoHS) has been in force in Europe since 2003 restricting the use of certain hazardous substances (e.g. lead, cadmium, mercury etc.) in electrical and electronic equipment and this is likely to be extended to other industrial sectors. For this reason there is intensive research to find alternatives to lead alloys and one favourable candidate is Sn-Cu.

This paper will describe a study carried out to obtain a deeper understanding of some of the factors affecting Sn-Cu electroplating. Experimental work, by means of Hull Cell tests, ultrasonic agitation and pulse plating, has been undertaken to understand the effect of these factors on the properties of the Sn-Cu coatings. A number of advanced analytical techniques, including scanning electron microscope (SEM), energy dispersive x-ray spectroscopy (EDS) and white light scanning interferometry (WLS), have been used to evaluate the characteristics of the Sn-Cu coatings, in terms of their surface morphology, chemical composition and microstructure.

Our experimental results showed that pulse plating techniques combined with high speed magnetic stirring during deposition had a strong effect on the characteristics of the Sn-Cu electrodeposits and aslo Sn whiskers developing from the deposit.
Electrodeposition of Sn-Ni Alloy As Anodes for Lithium-Ion Batteries
Authors: Zhang Jinqiu , Zhou Minjian , Chen Miaomiao , Yang Peixia , An Maozhong
Published: February 2020

Sn can form Li22Sn4 reversibly with Li and gets more exploration as a kind of anode materials for lithium ion batteries. Li22Sn4 has a high theoretical capacity of 994 mAh/g, however, along with a problem that the huge volume change during the Li insertion and extraction and the material’s pulverization, leading to the short cycle ability. Using Ni as the inert matrix for Sn atom can control the volume change of tin material. In this paper, Sn-Ni alloys were electrodeposited on copper foils from aqueous electrolytes containing tin dichloride, nickel sulfate, sodium citrate, disodium EDTA and ascorbic acid. When the concentration rate of [Ni2+] to [Sn2+] was 3 to 1, Ni-Sn alloy particles were 400nm in diameter. Ni3Sn4 were the main structure of the alloy, which increased the cycle life of the lithium ion batteries. The reversible specific capacity of the Sn-Ni alloy electrode can reach to 654mAh/g. By the composite deposition of graphene, the sizes of Sn-Ni grains decreased and the properties of Sn-Ni alloy anodes improved. Magnetic fields also have effect on the micromorphologies and structures of Sn-Ni alloy, which cause the improvements of the performance of lithium ion batteries.

 

References

[1] X. Li, Y. Zhong, M. Cai, et al. Tin-alloy heterostructures encapsulated in amorphous carbon nanotubes as hybrid anodes in rechargeable lithium ion batteries. Electrochimica Acta, 2013, 89(1):387-393.

[2] W. Zhang. A review of the electrochemical performance of alloy anodes for lithium-ion batteries. Journal of Power Sources, 2011, 196 (1): 13-24.

[3] J. Zhang, M. An, P. Yang, et al. Preparation method of tin / graphene composite cathode materials for lithium ion batteries. ZL 201510114745.5. Nov. 30, 2016.

Acknowledgments

Thanks for the supports by National Natural Science Foundation of China (51474080, 51304056).
TiO2 Nanotubes As a Matrice for Electrodeposited Si, Au, and CdSe
Authors: Kowalski Damian
Published: February 2020

The anodizing is a high-voltage electrochemical conversion process that forms barrier-type oxides or nanoporous/nanotubular layers on valve metals and alloys mainly depending on the composition of electrolyte used.[1] The key to achieve the ordered nanoporous/nanotubular structures is a displacement of the film material above the original surface position due to synergistic effect of pits generation (field assisted oxide dissolution), stress generated at the metal-oxide interface including electrostriction and plastic oxide flow switching the growth of the barrier-film to nanotube/nanopore. Typically, the TiO2nanotube array formed in organic electrolytes such as glycerol, dimethyl sulfoxide, ethylene-glycol is obtained in the form of close packed structure in which the nanotubes nearly stick together with the tube walls. A fundamentally different nanostructure from that is obtained in diethylene-glycol electrolyte. The nanostructure is characterized by free standing nanotubes separated by an interconnecting space much bigger than the thickness of nanotube wall (Fig. 1). [2,3] Such geometry gives possibility for deposition of secondary materials using electrochemical processes in view of improved wetting behavior of the nanostructure. [4] Herein we report on how to control the synthesis of nanotubes to achieve unique oxide geometries, we discuss functional properties of nanostructures and report an examples of composites formed between oxide layer and Si, CdSe, Au, Pt. An examples of the nanostructured energy storage devices will be demonstrated.[4]

References:

[1] D. Kowalski, D. Kim and P. Schmuki, Nano Today, 8(2013) 235.

[2] D. Kowalski, J. Mallet, J. Michel, and M. Molinari, J.Mater.Chem.A
3(2015) 6655.

[3] D. Kowalski, J. Mallet, S. Thomas, J. Rysz, B. Bercu, J. Michel and M. Molinari, Electrochim. Acta, (2016), 10.1016/j.electacta.2016.02.213.

[4] D. Kowalski, and P. Schmuki, Chem. Comm., 46(2010) 8585.

Fig. 1 SEM and TEM images for TiO2 nanotubes formed at 60V and 70V for 16h in diethylene glycol electrolyte containing 0.1M HF and H2O 2-4 wt.%. The right figure shows STEM and TEM images for Si electrodeposited on TiO2 nanotubes and applied as negative electrode in lithium ion battery.

Figure 1
Electrophoretic Deposition of MoS2 Thin Film As a Stable Counter Electrode for Quantum Dot Solar Cells
Authors: Nguyen Hoang Thai , Phap Ngo Huy , Le Thang Van , Nguyet Nguyen Thi Minh , Hai Le Viet
Published: February 2020

Molybdenum disulfide (MoS2) nanoparticle has been synthesized by a facile and rapid microwave in the presence of ethylene glycol can act as an excellent susceptor of microwave irradiation. The structure and morphology of MoS2are characterized by X-ray diffraction, raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that nanometer scaled (<100nm) molybdenum disulfide with different morphologies can be successfully fabricated by microwave liquid state method with different time and power.

MoS2 thin films were deposited on fluorine-doped tin oxide (FTO) conducting glass via electrophoretic deposition (EPD) from the as-synthesized MoS2 colloidal solution. The SEM-EDS analyses showed that MoS2 film were formed after 10 min deposition at varying applied voltages from 10 to 25 V. A high electrocatalytic activity of MoS2 films for S2−/Sn
2− redox couple, usually used as a mediator for quantum dot solar cells (QDSCs), has been observed by cyclic voltammetry measurements. The prepared MoS2/FTO counter electrode was used to fabricate QDSCs, in which the photoanode was two-layer CdS/CdSe adsorbed on a mesoporous TiO2 film and the electrolyte was a polysulfide solution.
(Invited) Transparent Electrode and Magnetic Permalloy Made from Novel2 Nanopaper
Authors: Chen Jinbo , Akin Meriem , Yang Lei , Jiao Li , Cheng Fan , Lu Pengbo , Chen Liao , Liu Detao , Zhu Hongli
Published: February 2020

We report a novel partial dissolution strategy to liberate uniform cellulose nanofibers with diameter of 5-10 nm from macroscopic cellulose fibers and promote separation of nanofibers in an aqueous environment by forming water-soluble sodium carboxymethylcellulose (CMC) through heterogeneous sodium acetoxylation of cellulose. With the obtained cellulose nanofibers, we fabricated nanopapers which exhibit a high optical transparency of 90.5 % (550 nm) with promising mechanical properties and high thermal stability. By directly depositing Ag nanowires on a wet nanofiber sheet, we fabricated a flexible transparent electrode with 86.5 % (550 nm) transparency and 26.2 Ohm/sq sheet resistance (Rs). Meanwhile, we studied the magnetic properties of sputter deposited thin film of permalloy on nanopaper which exhibited a similar magnetic coercivity and a close saturation magnetization to conventional silicon dioxide-based permalloy.
Effect of Thin Film Platinum Microelectrode Granularity on Corrosion under Electrical Stimulation
Authors: Huynh Nha Uyen , Yamada Naoya , Furukawa Hidemitsu , Youssef George , Khosla Ajit , Kassegne Sam
Published: February 2020

One of the fundamental investigations on neural interfaces for stimulation of damaged and innervated areas of the brain is focused on microelectrode arrays (MEAs). Most notably are micromachined devices of platinum electrodes insulated between polyimide, a flexible and patternable polymer.(1) Electrochemical impedance and cyclic voltammetry (CV) testings have shown that metal electrodes degrade and delaminate after only 2500 cycles whereas glassy carbon electrodes are robust enough to withstand 250,000 cycles. (2) Atomic force microscopy (AFM) images, as shown in figures 1(a) and 1(b), were obtained to compare the two types of electrodes and analysis has shown that glassy carbon electrodes have a much smoother surface topography than that of platinum electrodes. Other studies have confirmed that increased surface roughness decreases circuit yield. (3) We submit that if the metal deposition process is optimized to produce a less granular surface of the platinum electrodes, then the electrochemical performance of these MEAs should improve. In order to test this concept, devices will be fabricated under four different sputtering conditions where two parameters will be modified: the vacuum pressure and the distance between the target and substrate. The control MEAs will be fabricated at a pressure of 0.01 mbar (~7.5 mTorr) and a distance of ~10 cm. The next two sets of devices will have the same distance as the control but the pressure will be reduced by 25% and 50%. For the last condition the vacuum will be kept at 0.01 mbar and the distance will decrease to 5 cm. After which the surface morphology of the different platinum films will be studied using AFM and the circuit resistance will be tested electrochemically in a three electrode cell.

References:

1. Kassegne, S., Vomero, M., Gavuglio, R., Hirabayashi, M., Özyilmaz, E., Nguyen, S., Rodriguez, J., Özyilmaz, E., van Niekerk, P., Khosla, A., “Electrical Impedance, Electrochemistry, Mechanical Stiffness, and Hardness Tunability in Glassy Carbon
MEMS mECoG Electrodes”, J. of Microelectronics Engineering, Volume 133, Pages 36–44, 2015.

2. Vomero, M., Goshi, R., Dryg, I., Maxfield, T., Castagnola, E., Maggiolini, E., Ciarpella, F., Ordonex, J., Gueli, C., “

Glassy Carbon Based Microelectrode Array Technology for

Use in Long-Term Neural Recording and Stimulation with Superior Electrical and Electrochemical Properties”, (in process), 2015.

3. Logeeswaran, V., Chan, M., Bayam, Y. , Saif Islam, M., Horsley, D., Li, X., Wu, W., Wang, S., and Williams, R., “Ultra-smooth Metal Surfaces Generated by Pressure-Induced Surface Deformation

Figure 1
All Polymeric Electrochemical Biochip Array of Patterned Gold on Silver Inkjet Printed Polyimide
Authors: Pandey Richa , Beggiato Matteo , Sverdlov Yelena , Inberg Alexandra , Demarchi Danilo , Shacham-Diamand Yosi
Published: February 2020

Direct writing of patterned functional electronic materials provides a new path to low cost and high throughput fabrication technology for producing integrated flexible circuits. However, it is equally important to assimilate printing technologies with solution based deposition steps in the same environment to attain a continuous and useful manufacturing process[1]. Direct patterning by inkjet printer have advantages of being low capitalization and equipment cost, high material efficiency (less than 5% of material gets wasted) and elimination of processes like photolithography[2]. Nevertheless, printed materials are characterized today by poor electrochemical performance due to i) residues of the ink binding materials on the surface of the printed circuits; ii) texture and morphologies (i.e. roughness, porosity); iii) surface impurities such as oxides. Therefore, currently, ink-jet printed electrodes have inferior biosensing properties compared to common negative printed electrodes where the metal is deposited by physical, chemical or electrochemical methods. A very realistic and simple approach to solve this issue is solution based deposition of noble catalytic metals on printed seed layer. This two-step process provides a relatively pure noble metallic high quality surface with good electrochemical properties for biosensing application. Moreover, this process is compatible with most solid and flexible substrates and fabrication processes.

A simple and efficient method has been developed to fabricate flexible, patterned gold (Au) biochip array. Micro-patterns of silver (Ag) ink were printed and dried on polyimide substrates. These micro patterns served as the activating seed layer for electrochemical Au deposition. Au deposition was carried out on Ag ink printed microchip array for various intervals of time to determine desired thickness. The thickness and conductivity measurements were performed. To investigate bio-electrochemical properties of the Au deposited chips, electrochemical impedance spectroscopy and cyclic voltammetry will be applied. The biosensing capabilities will be studied by the chronoamperometric method for different enzyme concentration.

Keywords: Inkjet printing, bio-electrochemical , Biochip array, Direct patterning.
A Flow through Porous Electrode Cell Design for the All Vanadium Redox Flow Battery
Authors: Li Jialang , Fofana Daouda , Shakeri Hosseinabad Fatemeh , Roberts Edward P.L.
Published: February 2020

A new flow field using a flow-through design has been evaluated for the all vanadium redox flow batteries (VRB). By dividing the flow between flow-by and a portion of the flow going through the electrode, a significant improvement in the performance was obtained. A 5 cm2 carbon paper (39AA SIGRACET) electrode was used, and the gap between the membrane and each electrode was 2 mm. A vanadium electrolyte system using mixed sulfuric and hydrochloric acid was used. Charging / discharging cycles were performed and compared with the flow-by design. The polarization curve was also compared for a range of states of charge and flow rate. Moreover, the influence of the concentration of vanadium electrolyte and flow rate on the coulombic, voltage, energy efficiency and the pressure drop were evaluated for the new cell design.
Effect of Interdigitated Flow Field Geometry on Redox Flow Cell Performance
Authors: Gerhardt Michael R. , Wong Andrew A. , Aziz Michael J.
Published: February 2020

A large fraction of the cost of a flow battery installation comes from the high cost of separators and bipolar plates1. Optimizing the use of active area in flow batteries by maximizing power density allows cell stack engineers to reduce the amount of stack materials required. The design of flow fields has a significant impact on cell performance, including peak galvanic power density2,3. In this work, we present an experimental and computational study of interdigitated flow fields with varying dimensions. We demonstrate reduction of resistive and mass transport overpotential losses by altering the interdigitated flow field dimensions to reduce zones of mid-channel stagnant flow within the porous electrode. A two-dimensional model of an interdigitated flow field, coupling fluid dynamics and electrochemistry, is used to guide optimization of the channel, land, and electrode dimensions in the flow field.

To study the influence of mass transport on performance, a flow cell is assembled with an unstructured, flow-through porous electrode, with a flat plate replacing the interdigitated flow field. Even with this simplified flow field, discrepancies persist between observed experimental results and predictions from porous electrode theory. We report our progress toward understanding and resolving these discrepancies.

1. V. Viswanathan et al., J. Power Sources, 247, 1040–1051 (2014)

2. M. L. Perry, R. M. Darling, and R. Zaffou, ECS Trans., 53, 7–16 (2013)

3. R. M. Darling and M. L. Perry, J. Electrochem. Soc., 161, A1381–A1387 (2014)

Figure 1. Experimental results and computational predictions of overvoltages from a symmetric potassium ferrocyanide/ferricyanide flow cell using one of four different flow fields. The cell consists of one sheet of SGL 39-AA on each side of a Nafion 212 membrane. The active area of each flow field is 5 cm2.

Figure 1
Electrode Materials for the All Vanadium Redox Flow Battery Using Mixed Acid Electrolyte
Authors: Li Jialang , Fofana Daouda , Li Xiaoan , El Sawy Ehab , Birss Viola , Shakeri Hosseinabad Fatemeh , Roberts Edward P.L.
Published: February 2020

Operation of vanadium redox flow batteries at low (below 5◦C) and high (above 40◦C) temperatures presents a significant challenge for commercialization due to issues with the solubility of vanadium under these conditions. One strategy that has been developed is the use of a mixed sulfuric and hydrochloric chloride acid electrolyte to stabilize the vanadium species. In this study, the electrochemical characteristics of the mixed acid system was explored using cyclic voltammetry at low and high temperature, with a range of electrode materials, including carbon paper, graphite felt and nanoporous carbon scaffold (NCS). Scanning electron microscopy (SEM) was used to characterize the morphology of the electrodes materials. The results show that the mixed acid system stabilized the vanadium redox system and enable operation at higher concentrations, leading to significant improvement in electrochemical characteristics at low and high temperature. Also, NCS electrode materials were found to have higher activity than graphite paper and graphite felt for the vanadium redox systems in the mixed acid electrolyte.