bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hollow Cathode Plasma (HCP) Enhanced Atomic Layer Deposition of Silicon Nitride (SiNx) Thin Films Using Pentachlorodisilane (PCDS)
Authors: Hwang Su Min , Kondusamy Aswin L. N. , Zhiyang Qin , Kim Harrison S. , Kim Jiyoung , Hwang Byung Keun , Zhou Xiaobing , Telgenhoff Michael , Young Jeanette 
Published: February 2020

Silicon nitride (SiNx) films have drawn great attention due to the wide range of applications such as passivation layer, gate dielectric, spacer, charge trap layer, and diffusion barrier [1]. Conventionally used LPCVD and PECVD for SiNx deposition have limitations in terms of conformal deposition and thickness scalability. Since plasma enhanced atomic layer deposition (PEALD) is expected to overcome these shortcomings, several research groups have reported SiNx film deposition. A number of studies on PEALD SiNx process using various chlorine-containing silicon precursors have been reported due to their ease in synthesis as well as good thermal stability [2]. Recently, PEALD SiNx film using a novel chlorosilane precursor, pentachlorodisilane (PCDS, HSi2Cl5) with NH3/N2 plasma was reported [3]. Under the NH3/N2 plasma condition, PCDS enhanced the growth rate (approximately > 20 %) compared to the hexachlorodisilane (HCDS, Si2Cl6), but still showed relatively poor wet etch resistance. Inspired the film characteristics, we propose to explore the feasibility of improving the wet etch resistance of PEALD-SiNx films using the different gas mixture for plasma. It has been reported that the wet etch rate of SiNx films has a linear relationship with the hydrogen concentration in the films [1]. Compared to NH3/N2 plasma, N2-H2 (forming gas) plasma improves the wet etch rate possibly due to less N-H and H-N-H bonds in the SiNx films [2].
Herein, PEALD SiNx films using PCDS as Si precursor and N2-H2 (10 % forming gas) plasma as the reactant were evaluated. The combination with PCDS and N2-H2 plasma showed a relatively lower (approximately < 10 %) growth rate than NH3/N2 plasma under a range of process temperatures (270−300 °C) whereas the wet etch resistance to HF acid was improved (> 1.5 nm/min, 500:1 HF). Studying these results, we suggest the effect of hydrogen on film properties such as growth rate, film composition, and wet etch resistance.
[1] H.S. Kim, X. Meng, S.J. Kim, A.T. Lucero, L. Cheng, Y.C. Byun, J.S. Lee, S.M. Hwang, A.L.N. Kondusamy, R.M. Wallace, G. Goodman, A.S. Wan, M. Telgenhoff, B.K. Hwang, and J. Kim, ACS Appl. Mater. Interfaces 10, 44825 (2018).
[2] X. Meng, Y.C. Byun, H.S. Kim, J.S. Lee, A.T. Lucero, L. Cheng, and J. Kim, Materials 9, 1007 (2016).
[3] X. Meng, H.S. Kim, A.T. Lucero, S.M. Hwang, J.S. Lee, Y.C. Byun, J. Kim, B.K. Hwang, X. Zhou, J. Young, and M. Telgenhoff, ACS Appl. Mater. Interfaces 10, 14116 (2018).

Figure 1
Nanocomposites Based Self-Powered Electronic Systems: Investigating the Materials Properties for Energy Harvesters and Photodetectors
Authors: Aepuru Radhamanohar , Mangalaraja R.V. 
Published: February 2020

Flexible electronic devices have drawn potential interest and provide significant new insights to develop energy conversion and storage devices such as photodetectors and nanogenerators. Recently, self-powered electronic systems have captivated huge attention for next generation MEMS/NEMS devices that can operate independently by generating built-in field without any need of external bias voltage and have wide variety of applications in telecommunication, imaging, environmental and defence sectors. The basic physical process involved in these devices are charge generation, separation, and charge flow across the electrodes. Many inorganic nanostructures have been exploring to fabricate various optoelectronic and electromechanical devices. However, the interaction of nanostructures and their excited charge carrier dynamics, photoinduced charge separation, and fast carrier mobility are yet to be studied. The proposed research is to address one such area and to realize the self-powered electronic devices.
In the present work, nanocomposites of inorganic nanostructures based on ZnO, metal halide perovskites; and Polyvinylidene fluoride (PVDF) based nanocomposites are realized for photodetectors and nanogenerators. The characterization of the inorganic nanostructures is carried out through steady state optical absorption and luminescence spectroscopies as well as X-ray diffraction and high-resolution transmission electron microscopy (TEM) studies. The detailed carrier dynamics is investigated using various spectroscopic techniques such as ultrafast spectroscopy and broadband dielectric studies. The developed composite nanostructures exhibit significant optical and electrical properties, which have wide potential applications in various MEMS/NEMS devices such as photodetectors and nanogenerators.
Interfacial Design of Metallic 1T-MoS2/Carbon Nanotubes for High-Electrocatalytic Hydrogen Evolution Performance
Authors: Geng Dongsheng , Jayabal Subramaniam 
Published: February 2020

The development of effective non-noble metal based electrocatalysts for the electrocatalytic hydrogen evolution reaction (HER) at lower overpotentials has attracted tremendous attention due to its important role for various electrochemical energy storage devices.1,2

In this study, a simple hydrothermal approach is implied for the preparation of metallic 1T-MoS2/carbon nanotubes (1T-MoS2/CNTs), which acts as an efficient electrocatalyst for HER.3 Fig. 1a, b, and c show the TEM images of 1T-MoS2/CNT composite, in that the 1T-MoS2 consists of a few-layered nanometers in structure and the CNT are well distributed homogenously in the 1T-MoS2 nanosheets, which can reduce aggregation and restacking of the 1T-MoS2 nanosheets. In addition, it can be seen from the fig. 4d that the presence of more intrinsic defects in the 1T-MoS2 nanosheets (marked as circles) was observed, which might result in an expansion of the interlayer spacing. Moreover, the HRTEM image (Fig. 1d) confirmed the presence of the octahedral 1T phase (marked as square) in 1T-MoS2/CNT composite. Besides, 1T-MoS2/CNT composite has been characterized by EDX elemental mapping analysis (Fig. 1f), which shows the existence and homogeneous distribution of Mo, S, and C elements.
The tuning of catalytically more active sites and enhancement in the electron transport property can be achieved by designing of the defect-rich 1T-MoS2/CNTs composite material. The unique interfacial composition of the defect-rich 1T-MoS2/CNTs enables enhanced electrocatalytic HER performance with a low onset potential of 96 mV, a small Tafel slope of 54 mV dec-1 and low overpotential of 172 mV at a current density of 10 mA cm−2 (Fig. 1g). In addition, the 1T-MoS2/CNTs demonstrate superior long-term stability in acid conditions and the developed approach is easily applied to the large-scale production of efficient electrocatalysts. The electrocatalytic performance of 1T-MoS2/CNTs composite is also compared with the 1T-MoS2, CNTs, 2H-MoS2 modified electrodes and the commercial Pt/C catalyst.
This high-electrocatalytic HER performance is likely attributed to the synergistic effects between the MoS2 nanosheets and CNTS, and rich defects.4 Moreover, DFT calculations also have proved that 1T-MoS2/CNTs show higher free energy change for hydrogen adsorption (ΔGH) than the 1T-MoS2 and CNTs. This work provides a novel and simple strategy to design 1T-MoS2/CNTs for high-performance applications in energy storage fields.
References
1. S. Jayabal, G. Saranya, J. Wu, Y. Liu, D. Geng and X. Meng, J. Mater. Chem. A, 2017, 5, 24540-24563.
2. M. Chhowalla, H.S. Shin, G. Eda, L.-J. Li, K.P. Loh and H. Zhang, Nature Chem., 2013, 5, 263-275.
3. J. D. Benck, Z. Chen, L. Y. Kuritzky, A. J. Forman and T. F. Jaramillo, ACS Catal., 2012, 2, 1916-1923.
4. L.X. Chen, Z.W. Chen, Y. Wang, C.C. Yang and Q. Jiang, ACS Catal., 2018, 8, 8107-8114.

Figure 1
Influence of Α-Site Cations on Performance of Α2Ir2O7 Pyrochlore Oxygen Evolution Catalysts in Acidic Condition
Authors: Hubert McKenzie Austin , King Laurie Ann , Patel Anjli M , Bajdich Michael , Jaramillo Thomas F 
Published: February 2020

The acidic nature of proton exchange membrane (PEM) electrolysis coupled with the highly oxidizing conditions of the oxygen evolution reaction (OER) greatly limits viable options for catalysts that are both active and stable. Precious metal catalysts, such as IrOx, are high performing OER materials, but scarcity and high cost may limit widespread implementation. Pyrochlore catalysts of the form A2B2O7 (where A is typically a rare-earth or alkaline-earth metal and B is a transition metal) have emerged as promising active candidates with reduced precious metal content and intriguing stability. For example, Y2Ir2O7 has demonstrated excellent activity and stability under acidic OER conditions despite some leaching of the Y cation, potentially leading to the in situ formation of a new active phase during catalysis1.
In this work, the influence of the A-site cation on the activity and stability of Ir-based pyrochlore materials (A2Ir2O7) was systematically explored. Using a series of rare-earth metals, activity and stability were experimentally correlated with changes in the physical, chemical, and electronic properties to better understand the origin of the enhanced performance. This experimental work was supported by density functional theory (DFT) calculations. The fundamental insight gained will help to design OER catalysts with improved activity and reduced precious metal content, all without compromising stability.
Cyclic voltammetry, chronoamperometry, chronopotentiometry, and double layer capacitance were used to determine the electrochemical performance of the catalysts. Inductively coupled plasma mass spectrometry (ICP-MS) was used to quantify leaching of the A-site cations and Ir under acidic OER conditions and establish a relationship between the loss of material and the change in catalytic performance. This relationship was further investigated with DFT calculations. Additionally, the crystal structure, surface composition, and morphology of the catalysts before and after electrochemical testing were probed using x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM).

References:

Lebedev, D. et al. Highly Active and Stable Iridium Pyrochlores for Oxygen Evolution Reaction. Chem. Mater. (2017). doi:10.1021/acs.chemmater.7b00766
Highly Conductive Catalyst with Advanced Manufacturing for Efficient Oxygen Evolution Reaction
Authors: Yang Gaoqiang , Yu Shule , Li Yifan , Kang Zhenye , Bender Guido , Pivovar Bryan S. , Green Johney , Cullen David A. , Zhang Feng-Yuan 
Published: February 2020

The electrochemical water electrolysis is a convenient technique to store intermittent, sustainable energies, such as solar and wind, into high-purity hydrogen. The state-of-the-art electrocatalysts for oxygen evolution reaction (OER) are Ir/Ru-based materials. However, their scarcity and high costs hamper the industrialization of water electrolysis. In addition, the low electrical conductivity (~ 1000 Ω/□) of those catalysts and the sluggish multistep proton-coupled electron transfer of OERs significantly reduce the reaction sites and performances of water splitting.
To overcome those problems, this research will present a highly conductive multi-layer catalyst fabricated with advanced manufacturing methods. We employ spray printing, sputter coating, and inkjet printing to produce nafion layers, gold nanolayers (AuNL), and IrO2 catalyst layers, respectively. The mesoporous AuNLs provide the catalyst layer with not only excellent electrical conductivity (0.5 Ω/□) but also good proton permeability. Furthermore, the novel structure of the multi-layer catalyst in the electrolyser cell helps to directly investigate the influence of conductivity on OER kinetics by visualizing the generated oxygen bubbles, which enables the establishment of correlation between the conductivity and reaction sites. Most importantly, the faster OER kinetics can be achieved even with a much lower loading of IrO2 catalysts (as low as 0.1 mg/cm2) than the conventional IrO2 catalyst layer in pure water, acidic, and alkaline solutions. The novel multi-layer catalyst provides a new way to enhance the performance and reduce the usage of noble catalysts in energy conversion and storage devices.
Keywords: Inkjet printing, mesopores, high conductivity, ultra-low catalyst loading, water electrolysis.
Polysulfone-Based Membranes for Vanadium Redox-Flow Batteries
Authors: Karpushkin Evgeny A. , Komayko Alena I , Timoshenko Vadim A , Sergeyev Vladimir G. 
Published: February 2020

Redox flow batteries have been recognized as promising electrochemical energy storage devices, due to independent power and energy scaling, long cycle life, fast response, and no self-discharge during storage. A crucial part of a redox flow cell is the membrane which separates the anolyte and catholyte containers. A membrane for vanadium redox flow battery (VRB) should be stable and exhibit high proton conductivity as well as low vanadium species permeability.
Perfluorinated ion-exchange membranes such as Nafion® are currently among the most widely used separators for VRBs. However, the best-performance membranes recognized so far are generally expensive, and the crossover of vanadium species across the membrane is noticeable. Therefore, if a cheaper alternative membrane material is found, the cost efficiency of the battery will be improved.
We have evaluated earlier the applicability of membranes based on polyacrylonitrile (PAN) in redox-flow batteries using VBR as a model system. It has been shown that the tuning of PAN material microstructure via phase separation and/or hydrolysis provides the desired balance of proton conductivity and vanadium species permeability. The overall energy efficiency of the VBR cell built using the PAN-based membranes has been found comparable to that determined with Nafion® membranes.
In this contribution, we extended this approach to the manufacture of membranes based on polysulfone (PS). The porosity and hydrophilicity of the PS membranes was tuned via phase separation, incorporation of polymeric (poly-N-vinylpyrrolidone) or inorganic (silica) additives, and the procedure of the membrane conditioning. Major physico-chemical properties of the membranes (ion conductivity and water permeability) were systematically measured, and the operation of the model VRB assembled using the PS-based membranes was evaluated in comparison with the PAN and Nafion® membranes.
This study was financially supported by Russian Science Foundation (project no. 17-73-30006).
Lung-Inspired PEM Fuel Cells Built from Layered Printed Circuit Boards
Authors: Bethapudi Viswanath Sasank , Cho Jason I.S , Hack Jennifer , Shearing Paul R. , Brett Dan J.L , Coppens Marc -Olivier 
Published: February 2020

Homogenous, scalable, and uniform distribution of reactants at membrane-electrode assembly (MEA) level are critical to the performance of polymer electrolyte membrane (PEM) fuel cells. To achieve this, cathode flow fields were introduced that have fractal flow geometry, inspired by the air flow mechanism in lungs [1]. These were manufactured using direct metal laser sintering. Here, we discuss the design and characterisation of lung-inspired fuel cell flow plates using cheap and light printed circuit boards (PCBs) manufactured using computer numeric control (CNC) machining. X-Ray computed tomography (CT) scans of the developed fractal flow fields demonstrate a uniform and well aligned PCB plate assembly that results in a fractal hierarchy of flow channels, as shown in figure (1a) and (1b). Polarization performance at 70% reactant humidity and 45oC cell temperature for the fractal flow field was 12% higher than the performance of a single-serpentine, at 0.6V individual cell potential, as shown in figure (2).The cell temperature profile for the fractal flow field was more stable and uniform, compared to a rapid rise in profile of the single-serpentine one. The voltage decay measurements, at constant current density hold, indicate that voltages of fractal and single-serpentine flow fields vary within 2% and 6% of their initial voltage values, respectively, over a period of 6h continuous operation. Furthermore, Electrochemical Impedance Spectroscopic (EIS) measurements establish higher ohmic and mass transport resistances for the single-serpentine compared to the fractal flow field, at current densities ranging between 100mA/cm2 and 900mA/cm2.
Keywords: Fractal, X-Ray CT, EIS,CNC, PCB, lung-inspired, hierarchical
Reference:
[1] P. Trogadas, J.I.S. Cho, T.P. Neville, J. Marquis, B. Wu, D.J.L. Brett and M.-O. Coppens, 2018, A lung-inspired approach to scalable and robust fuel cell design. Energy & Env. Sci. 11, 136-143.

Figure 1
Electrocatalyst Evaluation of 3D Printed Microfluidic Membraneless Glucose Biofuel Cell with Integrated Pencil Graphite Electrodes
Authors: Bandapati Madhavi , Rewatkar Prakash , Krishnamurthy Balaji , Goel Sanket 
Published: February 2020

This work demonstrates for the first time the application of Pencil Graphite (PG) based enzyme nano biocomposite electrode substrates for a membraneless glucose biofuel Cell (GBFC) in a microfluidic environment [1]. PG is non-toxic, user friendly and prone to the environment with good mechanical rigidity and chemical inertness making it biocompatible. Low background currents, strong adsorption properties, wide potential window, good sensitivity and reproducibility, adjustable electro active surface area and ease of miniaturization make it an excellent candidate to employ as a working electrode [2]. A time-efficient and cost-effective process is proposed involving simple and easy steps for the fabrication of the PG electrodes [3].
After screening various grades of pencil leads, bioanode was fabricated from B grade PG by substantially increasing its surface area by coating carboxylated multiwalled carbon nanotube (MWCNT) through dipping method followed by the covalent immobilization of the anodic catalyst, glucose oxidase enzyme [4]. Likewise, the biocathode was fabricated from 5H grade PG by coating carboxylated multiwalled carbon nanotube through dipping method and electrodeposition of polyaniline (PANI) coating followed by the covalent immobilization of the cathodic catalyst, Laccase enzyme [5]. These electrodes were then inserted into a microfluidic co-laminar flow based membraneless GBFC as shown in Fig. 1a., designed and fabricated using a 3D printer. Glucose was used as fuel and air as oxidant with p-Benzoquinone (PBQ) and 2, 2- azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) in solubilized form as anodic and cathodic mediators respectively and the eletrochemical charecteristics were measured using polarization studies under pysiological glucose concentation conditions (40 mM, 37ºC, pH 7.0) by varying the flow rates, dimensions of the device and distance between electrodes. This portable microfluidic set up generated maximum power density of 10 μWcm-2, OCP of 500±5 mV and current density 64 μA cm-2 at a flow rate of 40 μlmin-1 which could sustain for more than 100 hours. Hence, this work successfully demonstrates the strong potential of using readily available and biocompatible PGs as low cost alternatives to carbon based electrodes to power miniaturized low temperature microelectronic devices and sensors.

Figure 1
Electrochemical Synthesis of Cu-Cu2o Composite Layers and Its Catalytic Properties Towards Ethylene Generation
Authors: Mech Krzysztof , Bisztyga-Szklarz Magdalena , Szacilowski Konrad 
Published: February 2020

Recently a number of articles concerning subjects related to limitation of greenhouse gasses emission or neutralization of greenhouse gasses present in atmosphere significantly increased. Global warming negatively influences on non-failure operation of ecosystem and due to glaciers melting resulting in water volume increase causing raising of water level in seas and oceans. Large number of negative factors resulting from global warming effect creating necessity of performance of intensified investigations going to development of technologies enabling limitation of emission or neutralization of greenhouses gasses through its conversion to chemical compounds which can be applied in synthesis of other useful chemical compounds or functional materials. Other important problem beyond limitation of CO2 amount in atmosphere is related to possibilities of its conversion to chemical compounds which can be used as energy carriers. It creates possibilities for its applications in renewable energy storage oriented systems. The proposed project is focused on photoelectrochemical conversion of one of main greenhouse gas, CO2 to ethylene.
The main scientific objective of performed studies was the development of methodology for electrochemical synthesis of binary composite Cu-Cu2O material. Copper is the only metal that exhibits very high selectivity for electrochemical conversion of CO2 to ethylene (1). Ren et al. observed similar effect in case of p-type Cu2O (2). Reported effects allow assumption that combination of both materials can be great solution in the frame of light supported electrochemical conversion of carbon dioxide to ethylene. Authors describe optimization of electrochemical synthesis process towards synthesis of composite coatings of wide composition range. Synthesis conditions were investigated starting from the thermodynamic analysis of the electrolyte. Conditions for synthesis were determined based on the results of voltammetric tests and electrochemical quartz crystal microbalance analyses. Synthesized coatings were characterized towards their composition, structure, morphology and catalytic properties towards electrochemical reduction of CO2 to ethylene.
References

Y. Kwon, Y. Lum, E. L. Clark, J. W. Ager and A. T. Bell, ChemElectroChem, 3, 1012 (2016).

D. Ren, Y. Deng, A. D. Handoko, C. S. Chen, S. Malkhandi and B. S. Yeo, ACS Catalysis, 5, 2814 (2015).

P. D. Tran, S. K. Batabyal, S. S. Pramana, J. Barber, L. H. Wong and S. C. J. Loo, Nanoscale, 4, 3875 (2012).