bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrode for Voltammetric Evaluation of Insoluble Particles
Authors: Lovander Matthew Douglas , Gillan Edward , Leddy Johna 
Published: February 2020

A working electrode was developed to test the electrochemical behavior of insoluble particles in aqueous acidic and basic electrolytes. The hydrogen evolution reaction (HER), oxygen reduction reaction (OER), and pseudocapacitive behavior of nickel phosphide, nickel oxide, and cobalt oxide were evaluated.
The electrode consists of a coiled copper wire in a (55:45 wt. %) mixture of graphite and paraffin wax, housed in either glass or polyvinyl fluoroethylene (PTFE) tubing. The malleability of the electrode surface allows for particles to be directly embedded into the surface without the use of binder materials such as Nafion or PTFE. The electrochemical behavior of modified and unmodified electrodes of both the developed carbon-wax electrode and a commercially available glassy carbon electrode (GCE) is presented. Cyclic voltammetry, linear sweep voltammetry, and chronopotentiometry were employed for electrochemical investigation into the hydrogen evolution reaction, oxygen evolution reaction, and pseudocapacitive behavior of nickel phosphide (NiP2), nickel oxide (NiO) and cobalt oxide (Co3O4) on both working electrode types. The PTFE electrodes performed well in both acidic and basic media and their performance is comparable to the GCE. The newly developed electrodes displayed reproducible electrochemical behavior and provide a method to evaluate insoluble particles voltammetrically.
The Effect of a Protective Overcoat on Mixed-Potential Sensor Response
Authors: Brown Shanice C. , Spernjak Dusan , Mukundan Rangachary , Reynolds Jonathan M. , Brosha Eric L. , Kreller Cortney R 
Published: February 2020

Nitrogen oxide (NOx) and ammonia (NH3) sensing technology is being developed for application in vehicle emissions monitoring of diesel and lean-burn gasoline engines. In lean-burn engines, Selective Catalyst Reduction (SCR) utilizes NH3 to reduce NOx. The purpose of the NH3 sensor is to ensure that the NH3 is completely consumed in the NOx reduction reaction, and it is not emitted from the tailpipe. Both the NOx and NH3 sensors described herein are mixed-potential sensors that measure the non-nernstian potential created at an electrode/electrolyte interface exposed to a mixture of reducing/oxidizing gases. The NOx sensor is composed of La0.8Sr0.2CrO3 (lanthanum strontium chromite) and Pt electrodes with a YSZ electrolyte and a protective porous ceramic overcoat. The NH3 sensor is composed of Au/Pd and Pt electrodes with a YSZ electrolyte and protective overcoat. The purpose of the overcoat is to protect the electrodes from contaminants such as heavy metals and water present in harsh exhaust environments. We examine the effect of the protective overcoat on the sensor performance. Preliminary data on the NOx sensors indicates that the overcoat serves as a thermal blanket; decreasing the temperature difference observed between the heater and the sensing element in bare sensors. Sensing characteristics of response time, selectivity and sensitivity will be compared and discussed.
Effect of Contaminants on the Performance of a Proton Exchange Membrane Fuel Cell
Authors: Tavakoli Bahareh , Weidner John W. 
Published: February 2020

The overall cost and performance of proton exchange membrane fuel cells (PEMFCs) are an issue of tradeoffs, and the optimal design depends on the application. For example, avoiding degradation via contamination by using expensive materials increases the initial cost to produce the system, but it can extend life and improve the overall performance. This may be desirable where reliability is paramount. In contrast, using less expensive materials reduces the initial cost, but at the expense of the life-time cost of the system and reduced performance.
During this study, a systematic and collaborative investigation was conducted to understand, characterize, and quantify the degradation mechanisms due to contaminants that arise from components that make up the fuel-cell system. Initially, the key contaminants that leach out of commercial assembly-aid materials were identified and screened for their detrimental effect on fuel-cell component performance (e.g. catalyst activity, membrane conductivity). Then, model compounds were selected and in-depth parametric studies were performed. In total, four model compounds in the assembly aid materials have been selected to study the degradation mechanisms, and the impact to PEMFC performance and durability of each compound was evaluated by in-situ infusion tests and in-situ membrane resistance tests. The results from these parametric studies were then used to develop mathematical models to quantify the performance loss and recovery of the fuel cell.
Effects of Preparation on the Silicon Nanowires Grown By Electroless Etching
Authors: Velez Victor H. , Mertens Robert George , Sundaram Kalpathy B 
Published: February 2020

Highly oriented SiNWs arrays prepared by electroless etching method can significantly suppress light reflection across a broad spectrum [1]. The antireflective nature of Silicon nanowires (SiNW’s) revealed by their black color and dull appearances have drawn the attention of researchers [2]. Reflectivity studies on these show a significantly decrease in optical reflectivity down to 1.3% for 10 µm long SiNWs arrays [3]. Electroless etching is a top-down technique for growing SiNWs and does not need costly and expensive equipment to grow SiNWs as bottom-up methods usually do.
The electroless process begins with the cleaning of silicon substrates. They were cleaned in acetone, methanol and deionized water, then blow-dried with N2. They are dipped in hydrofluoric acid (HF) 49% solution for 1 min to remove any remaining oxide.
The silicon (Si) wafers are dipped for 15 minutes at room temperature in an electroless solution prepared in a petri dish containing silver nitrate (AgNO3) and hydrofluoric acid (HF) [4].
The substrates are dipped and galvanic reactions disperse silver ions on their surface, losing silicon as SiF6. As a consequence of this etching process, the removal of Si via Ag ions results in vertically aligned arrays of SiNWs covered with silver dendrites.
At the end of the etching process, the samples were dipped in two baths of deionized water and placed in diluted nitric acid (HNO3) 20% to remove the Ag dendrite layer formed on top of the SiNW arrays. Reflectance on different methods to remove the residual silver particles from SiNW’s when using an unstirred, stirred and sonicated diluted nitric acid (HNO3) 20% solution are presented Fig 1.

Figure 1
Enhancing the Rate Capability of Hybrid Supercapacitors Based on Redox Active Electrolytes through High-Surface Area Reduced Graphene Oxide
Authors: Roldán Silvia , Bondarchuk Oleksandr , Carretero-González Javier , Rojo Teofilo , Mysyk Roman 
Published: February 2020

Electrochemical double layer capacitors, which are the most widespread type of supercapacitors, have inherent energy limitations due to the low energetic of electrostatic charge storage. Increasing the energy density of supercapacitors is therefore a major challenge to open up wider application market, with targeted energy values set nowadays at 20-30 Wh/kg. Ongoing energy improvement efforts focus on the following routes: i) materials and composites overcoming capacitance values of traditional nanoporous carbons; ii) innovative electrolytes; iii) hybrid supercapacitor configurations. A particular example of such work is the combination of redox active electrolytes and carbon materials in a hybrid configuration, which provides affordable aqueous-based systems allowing for more than doubling the maximum energy output. However, energy gains come at the expense of worsening power capability and cycle life, which are the main advantages of supercapacitors over batteries.
To alleviate the drawbacks of hybrid supercapacitors based on redox active electrolytes, we have developed an asymmetric system, in which a nanoporous activated carbon electrode is substituted by high-surface-area reduced graphene oxide (rGO). Importantly, rGO with surface area about 1000 m2 g-1 is made by a simple process route not involving any activation step.
Using high-surface-area rGO has led to a dramatic improvement in the rate capability of hybrid devices whereas the high surface area of rGO provided for effective charge balance. The high conductivity of rGO has allowed cycling hybrid cells up to a high current density of 6.5 A/g (considering the total active mass of both electrodes) without any significant capacitance fading. Significant energy improvements can further be expected by exploring different redox active electrolytes and graphene materials with even higher specific surface area.
The Catalytic Activity of Pd Supported on TiO2 Nanotubes on the Formic Acid Oxydation in Alkaline Media
Authors: Aldana-González Jorge , Montes de Oca-Yemha Maria Guadalupe , Olvera Juan Carlos , Romero-Romo Mario Alberto , Uruchurtu Jorge , Palomar-Pardavé Manuel 
Published: February 2020

Formic acid electrochemical oxidation was studied using an electrode formed by Pd electrodeposited on third generation TiO2 nanotubes (TiO2NTBs-Pd), see inset in Figure 1A, in an alkaline medium. The electrochemical response of TiO2NTBs-Pd electrode towards formic acid oxidation was better than those corresponding to Ti or TiO2 nanotubes, see Figure 1A. Figure 1 (B) shows the typical Pd voltammetric regarding both Pd oxide formation and its reduction. From CO adsorption, see Figure1B, the real area of Pd electrodeposited was measured. The formic acid oxidation on the TiO2NTBs-Pd electrode is shown in 1D.

Figure 1
Plastic and Flexible Micro-Electrochemical Supercapacitor Based on Cluster-Assembled Carbon
Authors: Soavi Francesca , Arbizzani Catia , Bettini Luca Giacomo , Milani Paolo , Piseri Paolo 
Published: February 2020

Flexible, thin micro-electrochemical supercapacitors (MES) are attracting much attention in electronics for their capability of delivering short power pulses with high stability over repeated charge/discharge cycling. Supersonic Cluster Beam Deposition (SCBD) is an effective strategy for the development of nanostructured, binder-free porous carbon electrodes. It consists in the deposition of low kinetic energy clusters producing films with very low-density and high porosity. The use of SCBD for carbon cluster deposition allows to obtain very high deposition rates and highly collimated beam (divergence <20 mrad) which are suitable for the room temperature deposition of patterned nanostructured films by using stencil masks on a wide variety of substrates including polymers. We exploited SCBD, for the development of a planar, high voltage MES featuring nanostructured carbon electrodes deposited on a flexible plastic Mylar substrate and ionic liquid-based electrolyte. Here, the electrochemical performance at different temperatures of the MES which operate above 2.5 V with a capacitance density approaching approaching 10 F cm-3,and delivering 9 mWh cm-3 and 2.5 W cm-3 above room temperature is reported.
ACKNOWLEDGMENTS
RFO, Ricerca Fondamentale Orientata, is acknowledged for financial support.
Understanding Field-Dependent Leakage Current Mechanisms in Amorphous Hydrogenated Boron Carbide As a Function of Electronic, Dielectric, and Disorder Parameters
Authors: Paquette Michelle M. , Nordell Bradley J. , Keck Christopher L. , Bhattarai Gyanendra , Nguyen Thuong D. , Purohit Sudhaunshu , Caruso A. N. , Lanford William A. , King Sean W. 
Published: February 2020

Thin-film carborane-based amorphous hydrogenated boron carbide (a-B
x
C:H
y
), grown by plasma-enhanced chemical vapor deposition (PECVD), has emerged as a promising semi-insulating, low-dielectric-constant (low-κ) (κ < 3.5) material for intra/interlayer dielectric (ILD) and/or copper diffusion barrier/etch stop applications. Of the many integration challenges faced by candidate materials for low-κ ILDs or more specialized layers, one of the most important is the need for extremely low leakage currents up to high electric fields. In the case of a-B
x
C:H
y
, the leakage current at a given field can span nearly ten orders of magnitude, depending on the fabrication conditions and resulting physical properties of a given film. In order to go beyond a brute force process–property approach toward optimizing the electrical properties in thin-film a-B
x
C:H
y
, we explore their origin and relationship to electronic, dielectric, and disorder properties.
This contribution will describe the charge transport mechanisms in a-B
x
C:H
y
films in different electric field regimes, which include Ohmic, space-charge-limited-current, and Poole–Frenkel behavior. These mechanisms, and the underlying electrical properties that define these mechanisms (e.g., resistivity, mobility, trapping), are related to individual and combined electronic (band gap), dielectric (electronic and atomic/distortion polarization), and disorder (Urbach energy, Tauc parameter, dispersion energy) parameters. We further discuss how balancing the contributions of these different parameters via hydrogen and carbon content, through varying growth parameters, allows us to control the underlying charge transport mechanisms at both low and high fields, to ultimately obtain leakage currents on the order of 10–8 A/cm2or lower at 2 MV/cm.

Figure 1. (a) Leakage current density (J) as a function of electric field (E) for a selection of a-B
x
C:H
y
films. (b) and (c) Correlations between charge transport and disorder parameters: zero-field mobility extracted from steady-state space-charge-limited current measurements (μ
0(SS-SCLC)) as a function of E
g
E
u
B
–1/2 disorder parameter, and resistivity (ρ) extracted in Ohmic regime as a function of dispersion energy (E
d).

Figure 1
Understanding the Effect of MgO Interfacial Layer on ZnO/High-K/Fto Transparent Thin Film Transistor for Large-Area Transparent Electronics Applications
Authors: Jha Rashmi , Thapaliya Prem 
Published: February 2020

ZnO and doped-ZnO based thin film transistors (TFT) have been widely studied for transparent electronics applications [1-2]. However, majority of the previous work have evaluated the performance of TFT using Indium Tin Oxide (ITO) as transparent gate electrodes which is expensive and may not be sustainable for large-area transparent electronics applications, such as transparent electronics integrated glass windows and glass walls in buildings [3-4]. In addition, replacing ITO with low-cost and scalable material such as Fluorine-Doped Tin Oxide (FTO) coated glass substrates also has potential to reduce the cost of displays in consumer electronic devices. Towards addressing this issue and extending the application of ZnO-TFT in large-area transparent electronics that is cost-effective and sustainable, we have evaluated the performance of ZnO TFT with commercially available FTO as gate electrodes. ZnO was deposited at room temperature using RF magnetron sputtering while reactively sputtered HfO2, deposited at 300◦C, was used as high-k gate dielectric. The devices indicated well-behaved transistor characteristics with field effect mobility of 0.84 cm2V-1s-1, the ON/OFF current ratio of 2.5×103 and sub-threshold swing 140 mV/decade. To understand the cause of low field effect mobility and large sub-threshold slope, the defect characteristics at ZnO/HfO2 interface was studied using admittance spectroscopy (Gp/ω vs. ω) measurements. The interface state density was found to be on the order of 1013 eV-1 cm-2 which is 1-2 orders of magnitude higher than typically reported for ZnO-TFT [5-6]. This work will present our systematic understanding on the role played by FTO electrode in governing the FTO/HfO2 and HfO2/ZnO interface characteristics which finally plays an important role in governing the performance of the transistor. In particular, the role of fluorine diffusion in the stack and possibility of engineering the FTO/HfO2 and HfO2/ZnO interfaces via the insertion of interfacial layers such as MgO will be presented and supported with experimental results.
[1] R. L. Hoffman, B. J. Norris, and J. F. Wager, Appl. Phys. Lett. 82, 475 (2003)
[2] J. S. Seo, J. H. Jeon, Y. H. Hwang, H. Park, M. Ryu, S. H. Park and B.S. Bae, Nat. Sci. Rep, 3, 2085 (2013)
[3] L. Zhang, J. Li, X. W. Zhang, X. Y. Jiang, and Z. L. Zhang, Appl. Phys. Lett. 95, 072112 (2003)
[4] J. Zhang, Z. Li, L. Shen, C. Ye, B. Wang, and H. Wang, Thin Solid Films 544, 281 (2013)
[5] P. F. Carcia, R. S. McLean, and M. H. Reilly, Appl. Phys. Lett, 88, 123509 (2006)
[6] J. J. Siddiqui, J. D. Phillips, K. Leedy, and B. Bayraktaroglu, IEEE Electron Devices Lett.32, 1713 (2011)
Growth of Nickel Silicide/Platinum Silicide Axial Nanowire Heterostructure through Solid-State Reaction
Authors: Wu Yen-Ting , Huang Chun-Wei , Chan Jui-Yuan , Huang Yu-Ting , Chiu Chung-Hua , Hsieh Yu-Shun , Chang Chia-Fu , Wu Wen-Wei 
Published: February 2020

Nickel monosilicide (NiSi) with the addition of platinum has been highly regarded as paramount candidate for excellent contact in semiconductor industry for its low electrical resistance and high thermal stability. With the transition of device dimension to nanoscale, 1-D NiSi nanostructures with excellent metallic contact to Si nanostructures have attracted much interests in the field of nanoelectronics. Therefore it is important to investigate the nickel silicide formation and transformation mechanism in 1-D system to gain the control of specific nanostructure since it different from bulk system.
In this work, we fabricated two different metal pads (nickel/platinum), served as contact with silicon nanowires (NWs) to study nickel silicide/platinum silicide axial heterostructure through solid-state reaction. The as-fabricated Si NWs with two contact electrodes were annealed in ultrahigh vacuum in-situ transmission electron microscopy (UHV in-situ TEM) at 550℃ for observation of the reaction process. The structural information of dual silicide nanostructure was analyzed by spherical aberration corrected scanning transmission electron microscopy (Cs-corrected STEM) and we successfully got nickel silicide/platinum silicide axial heterostructure.
With the understanding of the nickel silicide transformation mechanism in 1-D system, reliable 1-D NiSi nanostructures would be generally applicable to semiconductor industry.
An Easy Stereo-Specific and Regio-Selective Reaction for the Synthesis of Ester-[70]-Fullerene Derivatives
Authors: Castro Edison , Echegoyen Luis 
Published: February 2020

Medicinal chemistry is one of the many fields where fullerene derivatives have been shown to be active and useful.[1,2] Wudl and coworkers reported the interactions of [60]-fullerene derivatives with the active site of HIV protease, driven by the lipophilicity of the carbon cage.[3] Unfortunately, fullerene derivative applications in this field are hindered mainly by their low water-solubility. To date, water-soluble fullerene C70 derivatives have not been extensively investigated. The lack of low symmetry of the C70 cage makes its selective functionalization more challenging than for C60. Therefore, just a few C70 water-soluble derivatives have been reported. [4,5] Here we report an efficient stereo-specific and regio-selective reaction for the synthesis of ester-pyrrolidinofullerene derivatives. These compounds are good precursors for the synthesis of their corresponding water-soluble carboxylic acid-pyrrolidinofullerenes.

Figure 1. Stereo-specific and regio-selective 1,3-dipolar cyclo-addition reaction of ester-[70]-fullerene derivatives.

A. Jensen, S. Wilson, D. Schuster, Bioorg. Med. Chem. 1996, 4, 767.

T. Da Ros, M. Prato, Chem.
Commun. 1999, 663.

S. Friedman, D. DeCamp, R. Sijbesma, G. Srdanov, F. Wudl, G. Kenyon, J. Am. Chem. Soc.
1993, 115, 6506-6509.

P. Witte, F. Beuerle, U. Hartnagel, R. Lebovitz, A. Savouchkina, S. Sali, D. Guldi, N. Chronakisd, A. Hirsch, Org. Biomol. Chem. 2007, 5, 3599.

A. Kornev, A. Peregudov, V. Martynenko, J. Balzarini, B. Hoorelbekec, P. Troshin, Chem. Commun.
2011, 47, 8298–8300.

Figure 1
Boron-Doped Reduced Graphene Oxide (B-RGO) and Its Application to L-Cysteine Sensing
Authors: Chen I-Ting , Lu Hsin-Che , Chang Ting-Hsiang , Huang Li-De , Ho Kuo-Chuan 
Published: February 2020

In this study, we prepare a boron-doped reduced graphene oxide thin film on the screen printed carbon electrode (SPCE) for the electrochemical sensing of L-cysteine (L-cys). L-cysteine, a sulfur containing amino acid, plays a crucial role in regulating the biological activity of certain proteins, peptides and enzymes. Low level of L-cys is related to myriad of diseases, including slow growth in children, depigmentation of hair, lethargy, liver damage, loss of muscle and fat, skin lesions, and weakness.[1] However, current L-cys sensing techniques require intensive pretreatments[2
,
3]as well as purifications. As a result, developing a relatively easy, selective and sensitive L-cys biosensor in physiological study and clinical diagnosis is highly demanded.
In the electron energy loss spectroscopy (Fig. 1 (a)), the peaks of π*(~190 eV) and σ*(~200 eV) anti-bonding orbitals on the K-edge of boron (B) revealed the hybridized sp2-bonded B atoms in the graphene nanosheet. These two peaks indicates that the substitution doping is the dominate type of doping. The STEM-EELS mapping of B-RGO (Fig. 1 (b)) confirms that dopant B (green) is uniformly distributed on the reduced graphene oxide.
Electrochemical characterization shows different performances among bare SPCE, RGO/SPCE and B-RGO/SPCE in Fig. 1(c). The results show that with the help of boron, B-RGO (B=9.6%) possesses good electrocatalytic ability to L-cys by decreasing the overpotential and increasing the current density of the irreversible oxidation reaction. Fig. 1(d) shows a plot of the current density of the B-RGO/SPCE as a function time at various L-cys concentrations. The current density increases linearly with the increased L-cys concentration, as shown in the inset. The sensitivity of the B-RGO/SPCE is 20.7 mAcm−2M−1. The limit of detection (LOD), based on a signal-to-noise ratio of 3, for the B-RGO/SPCE is 0.07 μM.
[1] S. Shahrokhian, Anal. Chem. 73 (2001), 5972
[2] G. Chwatko, E. Bald, Talanta,52 (2000) 509.
[3] K. Arlt, S. Brandt, J. Kehr, Journal of Chromatography A, 926 (2001) 319.

Figure 1