bluuebunny/crossref_metadata_2025_split huggingface dataset:
Addition of an Eco-Friendly Corrosion Inhibitor in Self-Assembled Monolayers Coatings to Improve Pitting Corrosion Resistance of Stainless Steel
Authors: Rougier Agathe , Melot Jean Marie , Doche Marie-Laure , Touyeras Francis , Roizard Xavier , Lallemand Fabrice , Hihn Jean-Yves 
Published: May 2020

In automotive industry and equipment manufacturers, treatment by phosphatation [1] is used both as an adhesion primer before painting and as a lubricant coating [2].This treatment also offers a good protection against corrosion. However, phosphatation is quite harmfull for the environment, producing a lot of waste to be treated. With regards to toxicity, it is composed of concentrated acids, nitrates and nitrites. Eventually, OEM are working to reduce the thickness of this coating which is typically in the range 2-30 µm. The objective of our research is to propose an alternative to steel/phosphate systems by thin organic coating on 304 stainless steel, a low carbon content substrate free of Molybdene available at affordable costs
To fit with the requiered specification while being as attractive as possible, this alternative coating must present a thickness reduced to a few nanometres, be environmentally friendly, non-toxic and easy to use. It must keep the main properties of phosphatation which consist in adhesion or anti-wear. Self-assembled Monolayers (SAMs) [3] coatings were chosen with addition of Aloe Vera as an ecological corrosion inhibitor [4][5]. SAMs are tunable by adjusting either their terminal group or the length of the carbon chain to obtain the desired surface properties and corrosion resistance. Three different terminal groups combined with four carbon chain lengths have been tested to find the molecule providing the best protection against corrosion.
An electrochemical study is carried out to quantify protection against pitting corrosion in a chloride-containing medium. The substrate used being a 304 stainless steel. As pitting corrosion mechanism involves both stable and unstable pits, two types of electrochemical methods are used. Pulsed potentials technic will highlighted unstable pits, while stable pits are analysed by cyclic voltammetry. These measurements are supported by surface analysis (SEM, EDS).
[1] T. W. COSLETT, Treatment of iron or steel for preventing oxidation or rusting, British patent 8667 and US patent 870937, 1906 et 1907
[2] J. BOGI, Phosphate conversion coatings on steel, J Mater Sci (1977) 12, 2235-2240
[3] A. ULMAN, Formation and structure of self-assembled monolayers, Chem. Rev. 1996, 96, 1533-1554
[4] Devarayan, Kesavan, Green Inhibitors for Corrosion of Metals: A Review, Chem Sci Rev Letts, (2012)
[5] M. MEHDIPOUR, Electrochemical noise investigation of Aloe plant extract as green inhibitor on the corrosion of stainless steel in 1M H2SO4, J. Ind. Eng. Chem, (2015), 21, 318-327

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(Invited) Magneto-Ionic Control of Heterostructures and Interfaces
Authors: Liu Kai 
Published: May 2020

Magneto-ionic approaches for modifying ion distributions in metal/oxide heterostructures offer exciting potentials to control material properties. Our recent studies show that such magneto-ionic effect, even though initiated at metal/oxide interfaces, can extend deep into the rest of the oxide films and drastically tailor their physical properties [1-4].
In antiferromagnetic systems, we have previously demonstrated a controllable positive exchange bias in GdFe/NiCoO [1], and that the oxygen migration can be reversibly driven by an electric field [2]. Recently, we have observed a strong exchange bias in Gd/NiCoO due to the magneto-ionic effect, above the Gd Tc. After electric biasing, up to 35% enhancement of the exchange bias is observed, which can be reset by field-cooling.
In studies of cuprates, we show a simple, scalable approach to tune superconductivity [4]. A thin Gd layer (up to 20 nm) deposited onto epitaxial YBCO films (100nm), is found to leach oxygen from deep within the YBCO and suppress the superconductivity. These effects arise from the combined impact of redox-driven electron doping and modification of the YBCO microstructure.
In ferromagnets chemisorbed with submonolayer oxygen, we have observed strong DMI induced by chemisorption at room temperature. The sign of this DMI and its surprisingly large magnitude are derived by examining the oxygen coverage dependent evolution of domain wall chirality. The large induced DMI has enabled direct writing of magnetic skyrmions.
Our findings demonstrate an effective solid-state ionic approach to control a wide variety of magnetic functionalities, opening up possibilities for electric gating.
This work has been supported by the NSF (DMR-1610060, ECCS-1611424, DMR-1905468, ECCS-1933527) and the nCORE SMART center through SRC/NIST.
[1]. Gilbert, et al, Nat. Commun.,
7, 11050 (2016).
[2]. Gilbert, et al, Nat. Commun.,
7, 12264 (2016).
[3]. Gilbert, et al, Phys. Rev. Mater.
2, 104402 (2018).
[4]. Murray, et al, arXiv: 1911.07275.
Defect Chemistry and Oxygen Ionic Conducting Properties of Gd2O3 at Elevated Temperatures
Authors: Kim Sunho , Tuller Harry L. 
Published: May 2020

Gadolinium sesquioxide (Gd2O3), an oxide exhibiting outstanding thermal stability, wide bandgap (>5eV) and relatively high dielectric constant (>14), is attractive as a high-k dielectric for CMOS, particularly when high temperature processing is required. However, in contrast to its conventional application as an electrical insulator, recent research on magneto-ionic devices suggests that Gd2O3 can serve as a solid electrolyte for field driven devices operating near room temperature. [1][2] According to previous research, proton transport in Gd2O3 is relatively swift among the binary oxides. [3] However, the defect chemistry and the oxygen ion conductivity of Gd2O3 have only been researched to a limited extent. In this work, we investigate the defect chemistry and electrical properties of doped and phase controlled Gd2O3 by impedance spectroscopy, as a function of oxygen partial pressure and temperature.
Nominally undoped, as well as intentionally donor and acceptor doped cubic and monoclinic phase polycrystalline specimens of Gd2O3 were prepared. Studies on the two different phases were possible since the monoclinic phase can stabilize below ~1420 K as a metastable phase. Ca2+& Sr2+and Ce4+& Zr4+ were used as acceptor and donor dopants respectively. 2-point impedance measurements were conducted on samples over a wide range of pO2 (10-12
atm – 1 atm) and for 5 isotherms ranging from 695 – 895 ˚C.
By analyzing the measured conductivity in terms of the developed defect model, relevant thermodynamic and kinetic parameters were extracted. In bixbyite (defective fluorite) phase Gd2O3, the formation enthalpy of anion Frenkel pairs was found to be 1.8 eV, lower than those of related fluorite oxides. The monoclinic phase Gd2O3 showed a somewhat higher, but still a rather low anion Frenkel pair formation enthalpy (2.1eV). Surprisingly, the more close-packed monoclinic structured Gd2O3 exhibited higher oxygen ion conductivity than more open cubic structured Gd2O3. The most highly ionic conducting samples of each phase were Ce doped cubic and Sr doped monoclinic Gd2O3, although the donor doped cubic had a significantly lower ionic conductivity and larger migration energy (1.7 eV and 0.8 eV respectively). All the Gd2O3 specimens showed mixed ionic and p-type conduction in synthetic air within the measured temperature range, implying excess oxygen nonstoichiometry.
Study of Si(100)-SiO2 Interface Trap Time Constant Distributions in Large Area Conventional MOSFETs-Comparison with Submicron Devices
Authors: Bauza Daniel , Guenifi Naima 
Published: May 2020

It seems well accepted now that Pb0 centers are the main defects at the Si(100)/SiO2 interface in conventional MOS transistors, even after forming annealing.
Besides, the charge pumping (CP) technique in which a MOSFET is repeatedly switched between inversion and accumulation has been widely used for studying single capture/emission events in deep submicron transistors [1]. In CP, the minority carriers stored into the interface traps in inversion recombine in accumulation with majority carriers from the substrate (n-channel case), providing a CP current which can be studied.
When it was accepted that in submicron MOSFETs the CP current, Icp, was given by Icp = f.q.N, f being the gate signal frequency, q, the electron charge, and N, the number of traps entering Icp, recently, Tsuchiya and co-workers [2,3] studying devices having SiO2 obtained by Rapid Thermal Oxidation, pointed out step heights equal to 2.q among a number of steps from 0 to 2.q. Pb0 centers with their donor-like and acceptor-like states in the lower and upper halves of the silicon bandgap, respectively, were thus measured for the first time in such devices.
As the energy at the interface that can be probed by CP is close to that between these two states, » 0.6 eV, the authors discussed the capability of CP to account for the two components with regard to the gate pulse characteristics.
In the present paper, the traps remaining electrically active at the Si(100)-SiO2 interface in large area conventional MOSFETs after the full technological process including forming gas annealing are studied. This is achieved using techniques developed in recent years that use the variation of the gate signal frequency for different gate voltage swings [4]. Trap time constant distributions are pointed out and studied as function of gate voltage and gate signal frequency. The results are discussed with regard to those reported in [2,3], to the CP models previously proposed and to CP curves simulation [5].
[1] G. Groeseneken et al. , IEEE Trans. Electron Devices 43, 940 (1996).
[2] T. Tsuchiya and Y. Ono, Jap. J. Appl. Phys. 54, 04DC01 (2015).
[3] T. Tsuchiya and P.M. Lenahan, Jap. J. Appl. Phys. 56, 031301 (2017).
[4] Y. Manéglia, F. Rahmoune, and D. Bauza, J. Appl. Phys. 97, 014502 (2004).
[5] D. Bauza, J. Appl. Phys. 94, 3239 2003).
(Invited) Semiconductor Nanocrystal Optoelectronics of Colloidal Quantum Wells
Authors: Demir Hilmi Volkan 
Published: May 2020

Solution-processed semiconductor nanocrystals have been attracting increasingly greater interest in photonics including spectrally pure color conversion and enrichment in quality lighting and display backlighting [1,2]. These nanocrystals span different types and structures of semiconductors in the form of colloidal quantum dots and rods to a more recently developing class of colloidal quantum wells. In this talk, we will introduce the emergent field of nanocrystal optoelectronics using solution-processed quantum dots and wells. In particular, we will present a new concept of all-colloidal lasers developed by incorporating nanocrystal emitters as the optical gain media, intimately integrated into fully colloidal cavities [3]. In the talk, we will then focus on our recent work on the latest rising star of tightly-confined atomically flat nanocrystals, the quasi-2D colloidal quantum wells (CQWs), also popularly nick-named ‘nanoplatelets’. Among various extraordinary features of these CQWs, we will present our most recent discovery that the CQWs uniquely enable record high optical gain coefficients among all colloids [4]. In addition, we will show the controlled stacking and assemblies of these nanoplatelets, which provides us with the ability to tune and master their excitonic properties [5], and present the first accounts of doping them for high-flux solar concentration [6] and precise wavefunction-engineered magnetic properties [7]. Given their current accelerating progress, these solution-processed quantum materials hold great promise to challenge their epitaxial thin-film counterparts in semiconductor optoelectronics in the near future.
[1] H. V. Demir et al., Nano Today 6, 632 (2011).
[2] E. Mutlugün et al., Nano Letters 12, 3986 (2012); T. Özel et al., Nano Letters 13, 3065 (2013); X. Yang et al., ACS Nano 8, 8224 (2014).
[3] B. Güzeltürk et al., Advanced Materials 27, 2741 (2015); and ACS Nano 8, 6599 (2014).
[4] B. Güzeltürk et al., Nano Letters 19, 277 (2019).
[5] O. Erdem et al., Nano Letters 19, 4297 (2019); N. Taghipour et al., ACS Nano 12, 8547 (2018).
[6] M. Sharma et al., Advanced Materials 29, 1700821 (2017); M. Sharma et al., Chemistry of Materials 30, 3265 (2018).
[7] F. Muckel et al., Nano Letters 18, 2047 (2018).

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(Invited) Luminescent Organic Solids with Unusual Exciton Multiplicity
Authors: Perepichka Dmitrii , Hamzehpoor Ehsan , Liu Cheng-Hao 
Published: May 2020

High quantum yield luminescent organic solids are required for a number of optoelectronic applications, including organic light-emitting diodes (OLEDs) and transistors (OLETs), lasers, etc. The absolute majority of organic materials can only emit efficiently from their singlet excited states. Involving high-multiplicity states (such as triplets) in exciton dynamics has several established and potential benefits; it is required to overcome 25% theoretical efficiency in OLEDs and might enable various magneto-optical devices. We will report our recent findings of (i) purely organic (C, H, N, O only) room temperature phosphors[1] and (ii) stable free radical fluorophores with record-breaking efficiency of triplet and singlet emission, respectively. The lecture will discuss the molecular and supramolecular mechanisms in modulating the emission from high-spin excited states in organic solids.
[1] E. Hamzehpoor, D. F. Perepichka, Crystal Engineering of Room Temperature Phosphorescence in Organic Solids, Angew. Chem. Int. Ed. 2019, DOI: 10.1002/anie.201913393
Development of Modified Silicon Nanoparticles for Energy Storage
Authors: Nurpeissova Arailym , Mukanova Aliya , Bakenov Zhumabay 
Published: May 2020

Due to the outstanding electrochemical properties, lithium-ion batteries have become a widely used energy storage technology for diverse types of devices. However, rapid progress in portable electronic devices and electric vehicles requires further essential improvement in the power and energy densities of lithium-ion batteries (LIBs) [1]. Conventional LIBs technology has reached the limit of its gravimetric / volumetric energy densities and power capabilities, reducing its ability to power new electronic devices and / or work as large batteries [2].
Among the promising candidates for anode materials, silicon (Si) has several advantages, including high theoretical capacity (3579 mAh g-1 for Li15Si4 at room temperature), low reaction potential against cathode material, environmental compatibility, low toxicity, and low cost. However, for the practical implementation of Si anodes in LIBs, it is necessary to consider one big critical issue: adaptation of large volume changes. Significant change in volume (4300%) during lithiation / delitration, leads to the volume expansion and grinding of Si particles, which leads to a rapid loss of electrode capacity, as shown in Figure 1a
This work presents the development of a new technology for the preparation of a composite anode material based on spinel Li4Ti5O12 (LTO) and Si with the addition of polyacrylonitrile (PAN) by liquid-phase coating, which demonstrates a synergistic positive effect on the performance of Si anodes (Fig. 1b). The idea lies in the coating the surface of silicon particles with LTO and PAN to suppress the volume expansion and improve the conductivity. The unique structure of LTO with zero deformation during lithiation / delitiation will help to withstand the volume change whereas PAN coating will improve the conductivity of the whole system.
Acknowledgements
This work was supported by the research grant AP05133706 “Innovative high-capacity anodes based on lithium titanate for a next generation of batteries” from the Ministry of Education and Science of the Republic of Kazakhstan and Collaborative Research Program for 2020-2022 "Three-Dimensional All Solid State Rechargeable Batteries".
References
[1] J.M. Tarascon, M. Armand, Issues and challenges facing rechargeable lithium batteries, Nature. 414 (2001) 359–67. https://doi.org/10.1038/35104644.
[2] M.T. McDowell, I. Ryu, S.W. Lee, C. Wang, W.D. Nix, Y. Cui, Studying the kinetics of crystalline silicon nanoparticle lithiation with in situ transmission electron microscopy, Adv. Mater. 24 (2012) 6034–6041. https://doi.org/10.1002/adma.201202744.

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(Invited) A Thermodynamic Approach to the First Steps of Metal Deposition
Authors: Schuster Rolf 
Published: May 2020

The current response of an electrochemical system to a potential pertubation often contains contributions from many parallel processes. A prominent example is Cu underpotential deposition on Au surfaces, where the Cu deposition is accompanied by the coadsorption of anions. Conventional electrochemical methods like cyclic voltammetry mostly obtain information on the total charge and can therefore not a priori discriminate between the involved processes. Electrochemical microcalorimetry may provide additional, independent information, which may help to identify such processes. By measuring the reversibly exchanged heat during an electrochemical reaction, one directly obtains the reaction entropy of the electrochemical process, including all side reactions. Knowledge of the reaction entropy, together with information from conventional electrochemical methods may thus help to disentangle the elementary steps of an electrochemical process. In this contribution we will give examples for:
1. Anion adsorption on metal surfaces with and without metal underpotential deposition. The dependence of the entropy of the adsorption process for anion adsorption on Au(111) surfaces shows a characteristic variation with potential for all studied anions, which points to an interplay between the configurational entropy of the anion layer and structuring of water at the electrode surface. The entropy data will be corroborated by surface plasmon resonance experiments, which obtained information on the reaction volume of the processes.
2. Metal deposition and surface layer formation from metal complexes. The deposition of Ag from Ag-cyanide complexes will be discussed for different CN- Entropy data support the formation of a passivating AgCN layer from [Ag(CN)2]- at low CN- concentrations. The deposition of metallic Ag probably proceeds via direct reduction of [Ag(CN)2]- at all cyanide concentrations.
3. The steps of metal deposition from multi valent ions. The elementary steps of Cu deposition from aqueous Cu2+ solutions are studied by time-resolved heat measurements of the deposition process. The data point to a two-step process where the Cu+ - Cu2+ reaction is an electron transfer process in solution, independent of the ion transfer process to metallic Cu at the electrode.
(Invited) Synergy between Halides and Capping Molecules in the Shape-Selective, Solution-Phase Growth of Metal Nanocrystals: A Theoretical Perspective
Authors: Fichthorn Kristen , Chen Zihao 
Published: May 2020

Ag nanocrystals have promising applications in many cutting-edge technologies, which are highly dependent on their shapes. These nanomaterials are typically synthesized using the solution-phase polyol method, which involves AgNO3 salt, capping agent polyvinylpyrrolidone (PVP), and ethylene glycol as the solvent and reducing agent. Chloride and bromide are often added to achieve robust shape control. In the interest of achieving shape-selective syntheses, understanding the mechanistic origins of shape selectivity is important.
Previous theoretical/experimental studies indicate that the preferential binding of PVP to Ag(100) can produce kinetic nanocubes of sufficiently large sizes. Small nanocubes can be synthesized experimentally when chloride is present, while theory predicts that truncated nanocubes are thermodynamically preferred in the presence of chloride and truncated octahedra are thermodynamically preferred without chloride. Here, we use dispersion-corrected density-functional theory to investigate the possibility that there is a synergy in the binding of PVP and chlorine to Ag surfaces, through which nanocubes emerge as the preferred thermodynamic shape.
We study the co-adsorption of PVP dimers and Cl to Ag(100) and Ag(111). We find that the adsorption of Cl influences the binding of PVP in a facet-selective way, such that Cl weakens the binding of PVP to Ag(111) at moderate to high Cl surface coverages, while Cl strengthens the binding of PVP to Ag(100) at low to moderate coverages, before weakening it at high coverages. We construct a contour plot of Ag-PVP-Cl surface energies as a function of the solution-phase Cl and PVP chemical potentials and find the associated Wulff shapes of the Ag nanocrystals. We find that truncated octahedra are thermodynamically preferred at low Clconcentrations / chemical potentials under full protection of PVP and Ag nanocubes are obtained at high Cl concentrations. We also identify a regime at which PVP binds to Ag(100) facets with adsorbed Cl, but is absent from Ag(111) facets. In this regime, kinetic {100}-faceted nanoshapes are likely to be preferred. Time permitting, we will also discuss recent results with bromide. This synergy between PVP and halide indicate a rich ground for kinetic control of Ag nanocrystal structures.
Surfactant Removal from Colloidal Nanocatalysts Used for the the Electrochemical Reduction of CO2
Authors: Hou Yuhui , Hu Huifang , Bort Sami , Broekmann Peter 
Published: May 2020

Colloidal nanomaterials have attracted significant interest in the field of high-performance catalyst synthesis. Additives (surfactants) are commonly used in colloid chemistry to control nucleation and growth of the nano-objects from a homogeneous solution. The action of these additives often yields colloidal particles of well-defined size, shape and composition thus being a crucial pre-requisite for systematic studies on structure-reactivity correlations.1-2 However, when left behind on the colloid surface the surfactants might affect its activity or change the selectivity towards certain reaction products by sterically altering reaction sites on the colloid surface. Approaches of surfactant removal shape from the nano-objects which do not change their size and shape are therefore highly desired.
Herein, we report on a systematical investigation on various surfactant removal methods.
Among the surfactant methods studied (including but not restricted to thermal annealing, chemical washing, plasma treatment, and exposure to ozone) photonic curing stands out. Photonic curing is an exposure of matter to intense and short (µs) light pulses. This approach of catalyst activation will exemplarily be demonstrated on the basis of Cu nanowire (Cu-NW) catalysts synthesized by an oleylamine route.3 Whereas the 3D-networks of the as-synthesized Cu-NW catalysts predominantly produce hydrogen as CO2RR product, photonically cured Cu-NWs show a high selectivity towards ethylene formation reaching a Faradaic efficiency of FEC2H4 = 42.4% (JC2H4 = -7.8 mA cm-2, E = -1.1V vs RHE) which can be maintained during prolonged electrolysis of 110 h. The almost quantitative surfactant removal by the photonic curing was confirmed by XPS analysis.
A further beneficial effect of the photonic curing treatment is related to the substantially increased mechanical stabilization of the Cu-NW film on the support electrode induced by a ‘mild’ sintering of Cu-NWs which remains locally confined to their points of contact. A loss of catalyst material or delamination of the catalyst film from the support electrode during massive gas evolution can thus be prevented.
Figure 1. SEM image of Cu-NWs and CO2RR product distribution at -1.1V vs RHE (1 h electrolysis) derived from catalysts treated by various procedures for the removal of the surfactant.
References:
1. Li, J.; Chen, G.; Zhu, Y.; Liang, Z.; Pei, A.; Wu, C.-L.; Wang, H.; Lee, H. R.; Liu, K.; Chu, S.; Cui, Y., Nature Catalysis
2018,
1 (8), 592-600.
2. Gawande, M. B.; Goswami, A.; Felpin, F. X.; Asefa, T.; Huang, X.; Silva, R.; Zou, X.; Zboril, R.; Varma, R. S., Chem Rev
2016,
116 (6), 3722-811
3. Hou Y., Bolat S., Bornet A., Romanyuk Y., Guo H. P. Broekmann ACS Catal. 2019, 9(10), 9518-9529

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