bluuebunny/crossref_metadata_2025_split huggingface dataset:
EIS Investigation of a Single Pit on Cantor Alloy in Acidic Environment
Authors: Hou Yaojun , Sun Fan , Ogle Kevin , Gharbi Oumaïma , Turmine Mireille , Vivier Vincent 
Published: August 2024

High-entropy alloys (HEA) are an emerging class of materials with promising properties such as high strength and ductility, improved fatigue resistance, fracture toughness, and thermal stability. They show considerable potential for use as corrosion resistant alloys to support our infrastructure especially for use in extreme environments. In this work, we mainly focused on the typical Cantor alloy, which consists in a mixture of 5 elements CrMnFeCoNi in equimolar proportion. A huge amount of works has already been devoted to the study corrosion resistance of alloys in sulfuric acid [1] or in chloride containing solutions [2,3]. For the latter, the study of the pitting propagation remains challenging since this kind of corrosion initiates as a stochastic process.
Electrochemical impedance spectroscopy (EIS) is intensively used as a tool for corrosion research and is well suited for the identification of complex mechanisms. However, data analysis remains difficult in the case of pitting studies, which can be described schematically as n anodic sites in parallel at different states of evolution. In this work we report on EIS analysis performed on a single pit (Fig. 1a) in order to describe the various step of its evolution as a function of time, but also as a function of various parameters such as the chloride ion concentration or the corrosion potential. Single pits were obtained by studying the breakdown of the passive film using the pumped-micropipette delivery/substrate collection (Pumped-MD/SC) mode of scanning electrochemical microscopy (SECM). A detailed mechanism is proposed to account for EIS results obtained on a single pit (Fig. 1b) in order to explain results on usuals EIS measurements.
[1] J. Yang, J. Wu, C. Y. Zhang, S. D. Zhang, B. J. Yang, W. Emori et J. Q. Wang, « Effects of Mn on the electrochemical corrosion and passivation behavior of CoFeNiMnCr high-entropy alloy system in H2SO4 solution », Journal of Alloys and Compounds, 819, avril 2020, p. 152943, https://doi.org/10.1016/j.jallcom.2019.152943
[2] Camila Boldrini Nascimento, Uyime Donatus, Carlos Triveño Ríos et Renato Altobelli Antunes, « Electronic properties of the passive films formed on CoCrFeNi and CoCrFeNiAl high entropy alloys in sodium chloride solution », Journal of Materials Research and Technology, 9, no 6, novembre 2020, p. 13879-92, https://doi.org/10.1016/j.jmrt.2020.10.002
[3] Mengjiao Li, Qingjun Chen, Xia Cui, Xinyuan Peng et Guosheng Huang, « Evaluation of corrosion resistance of the single-phase light refractory high entropy alloy TiCrVNb0.5Al0.5 in chloride environment », Journal of Alloys and Compounds, 857, mars 2021, p. 158278, https://doi.org/10.1016/j.jallcom.2020.158278

Figure 1
High Throughput Manufacturing of Highly Ordered Mesoporous Thin Film Oxides for Hybrid-Polymer Nanocomposite Dielectrics
Authors: Colburn Thomas William , Collinson David William , Dauskardt Reinhold Horst 
Published: August 2024

Highly ordered mesoporous metal oxide thin films have potential to become integrated into widely impactful dielectric materials due to the tunable properties of the oxide and its polymer filling; however, current manufacturing techniques to form the mesoporous oxide greatly limit scalable fabrication. Sol-gel mesoporous metal oxides generated via traditional processes require multi-day aging and high temperature, prolonged curing processes to yield controlled porosity at the expense of manufacturability. Moreover, high cost and unstable alkoxide precursors require precision over the solution precursor pH and subsequent thin film aging humidity after deposition.
Solution combustion synthesis (SCS) is a next-generation method of generating metal oxides at reduced process temperatures (often <300 ºC) and using green precursors compared to the sol-gel approach. The metal oxide is typically produced from a metal nitrate, which provides both the metal cation and oxidant and an organic chelator fuel. The fuel acts to stabilize the cation against hydrolysis and to participate in the exothermic redox reaction that results in the metal oxide.
Here, we present porogen integrated rapid oxidation (PIRO) which utilizes the principles of SCS to fabricate large-area mesoporous thin films of AlOx in less than 1 hour and at a temperature of 230 ºC. The PIRO method uses low-cost precursors to generate micelles with a controllable open-cell porosity ranging from ~30 – 60% and with varying degrees of closed-packed cubic ordering at a nearly 95% reduction in overall processing time. We show the precursor chemistry can be deposited via ultrasonic spray or blade coating at up to 6 m/min to manufacture large area mesoporous oxides and demonstrate filling of the porous AlOx with TOPAS® polymer to generate a hybrid nanocomposite with a dielectric constant of 6.26.
Porous Dielectric Structure and Response Speed of Moisture Sensors
Authors: Ali Ronak , Swartz Aaron , Badhan Riasad Azim , Ilka Reza , Wang Yiju , He Jiangbiao , Chen Zhi , Ren Ning , Zhang Z George , Wu Gefei , England Roger 
Published: August 2024

Humidity sensors are typically made of alpha-alumina films as porous dielectric materials deposited through the anodic spark deposition (ASD) technique, a unique anodic oxidation method to deposit ceramic coatings on the exterior of metals. Close attention to the precise composition of electrolyte solution is crucial when mixing chemical compounds. Moreover, the ASD process, which happens during dielectric breakdown at the anode surface in an electrochemical cell, is clearly followed by visible sparking at the anode/electrolyte interface, leading to the formation of various ceramic coatings on metal substrates. Electrical breakdown happens over an anodized barrier layer, typically amorphous aluminum oxide, which has been produced on the metal anode. The local high temperature (>2000°C) produced by electrical sparks melts the amorphous aluminum oxide and converts it to alpha-aluminum oxide, forming the stable foundation for a reliable humidity sensor.
In this study, we produced a variety number of small pores to investigate the response speed of moisture sensors. The ASD current can be adjusted to control the number of small pores. The smaller current gives a greater number of small pores. We focused on low-humidity sensors, often referred to as dew-point sensors. In fabrication of dew-point sensors, Scanning Electron Microscopy (SEM) was used to examine and determine the size of pores. Three different currents, 30 mA, 25 mA, and 10 mA, have been tried for comparative analysis of small pores existing within large pores. Two pores have been measured for current 10 mA, resulting in sizes of 47 nanometer (nm) and 71 nm, respectively. Similarly, three small pores for current 30 mA were measured with sizes of 32 nm, 42 nm, and 31 nm respectively. After the testing of low-humidity (dew-point) sensors, we found that the number of small pores does not significantly affect the response speed of the sensors.
Operando and Ex-Situ Studies of Columbite Electrode Materials
Authors: Friskey Matthew Harry , Keenan Luke , Amboage Monica , Payne Julia Louise 
Published: August 2024

Storing and utilising electricity from renewable sources is of growing importance as we move away from our reliance on fossil fuels. Batteries and supercapacitors are becoming ever more present in our day to day lives; in order to improve the next generation of batteries and supercapacitors, we must understand on an atomic scale what happens to electrode materials upon charge and discharge. In order to do this, we must combine structural and electrochemical studies, using techniques which use both different length scales and different timescales. These experiments are known as operando experiments and are a valuable tool in analysing new materials for energy storage.
Transition metal niobates of the columbite structure (MNb2O6, M = transition or alkali earth metal) have previously been studied for their photocatalytic and magnetic properties but recently have garnered interest as negative electrode materials for batteries and supercapacitors.1 In this study, a series of columbite materials have been studied using a range of operando and ex-situ techniques. Samples were prepared using both solid-state synthesis2 and solution methods. Ex-situ X-ray diffraction and scanning electron microscopy were used to characterise the columbites prior to electrochemical testing. Operando X-ray absorption spectroscopy and operando Raman studies have been used to probe the changes in oxidation state of the transition metals and local structure upon charge/discharge.
References

Yang, X. Zhao, F. Liao, Q. Cheng, L. Mao, H. Fa and L. Chen, Sustain. Energy Fuels, 2021, 5, 3039

Garía Alvarado, A. Orera, J. Canales-Vázquez, and J. T. S. Irvine, Chem. Mater., 2006, 18, 3827-3834

Figure 1
Understanding the Origin of Voltage Hysteresis in Disordered Rocksalt Cathodes
Authors: Kim Byunghoon , Ceder Gerbrand 
Published: August 2024

Lithium-rich cathodes are regarded as promising energy storage materials due to their high energy densities. However, voltage hysteresis presents challenges to maximizing their energy efficiency and practical implementation. Voltage hysteresis has generally been associated with transition metal migration and oxygen dimer formation within the structure. To understand the contribution of specific structural disorder to voltage hysteresis, one needs to consider the kinetics of the formation and recovery of each of these.
In this work, we clarified the mechanism by which oxygen dimerization and transition metal migration induce voltage hysteresis using lithium-rich disordered rocksalt cathodes as a model compound. We identify the type of structural transformations that occur at an exceptionally rapid rate, potentially saturating during room-temperature ab-initio molecular dynamics simulations lasting several hundred picoseconds. This clarification indicates that the formation of certain structural disorder is not always directly linked to hysteresis. Furthermore, we confirm a correlation between oxygen dimerization and transition metal migration, demonstrating that they mutually promote each other. Our work provides a mechanistic understanding of how structural disorder induces voltage hysteresis in lithium-rich cathodes, thereby reconciling the debate over the cause of hysteresis.
Phase-Field Modeling of Electrolyte Transport Properties and Elasticity Modulus in Suppression of Dendrite Growth in Solid-State-Lithium-Ion-Batteries
Authors: Pala Raj Ganesh , Kankani Komal , Chakraborty Pritam 
Published: August 2024

Dendrite formation in batteries is a critical issue that affects battery performance and lifespan. Solid-state electrolytes have gained attention due to their advantages such as compactness, higher energy density, and enhanced safety. This study investigates dendrite growth in batteries via phase field simulations utilizing a grand potential-based phase field model. The simulations are executed using the MOOSE (Multiphysics Object-Oriented Simulation Environment) framework, a Finite Element Method (FEM) based solver known for its modular approach and proficiency in handling complex multi-physics problems.
Initially, the study considers a pure lithium anode and a 1M LiPF6 electrolyte for the liquid case. To explore the benefits of solid electrolytes, a fictitious solid electrolyte with transport properties similar to the liquid electrolyte but having different mechanical properties is considered. The mechanical impact resulting from the volume changes due to lithium deposition is not accounted for in the liquid electrolyte model. However, the solid electrolyte model addresses this by modifying the Butler-Volmer kinetics and incorporating the influence of stresses on the localized lithium deposition. Sensitivity analysis is performed for various parameters in both the liquid and solid electrolytes. The results indicate that dendrite growth is reduced with decreased applied over-potential and interfacial energies. For solid electrolytes, an additional parameter, increased Young’s modulus, contributes to reduced dendrite growth.
The evaluation of dendrite growth involves quantifying surface roughness using the root mean square (RMS) approach. The elasticity modulus significantly influences dendrite formation, with higher values in materials like LLZO, and glass Li3PS4 exhibiting lower dendrite growth, while lower values in polymer-based materials like P(VDF-HFP) and PVDF/CAB/PE exhibit higher dendrite growth. The solid electrolyte acts as a crucial mechanical barrier, influencing the dendrite tip growth rate and ensuring uniform electrodeposition throughout the dendritic structure. Furthermore, the work investigates the impact of the cathode on dendrite growth. The contraction of the cathode provides additional space for dendrites to move, leading to reduced compressive stresses and increased dendrite growth. Conversely, higher compressive stresses suppress dendrite growth.
Transient Chemo-Mechanical Model of Lithium Plating Impacted by External Pressure
Authors: Meyer Julia , Mukherjee Partha P. , Roberts Scott A. 
Published: August 2024

To meet the ever-growing need for high capacity, fast-charge batteries, lithium anodes have been considered a direct upgrade to previous commercial anode materials thanks to their high gravimetric density and low coulombic efficiency. However, their implementation into crucial applications such as electric vehicles has been hindered by safety issues during and at the end of their operational lifetime. Over hundreds of cycles, nonhomogeneous plating and stripping of lithium on the anode surface encourages the growth of dendrites, which eventually lead to capacity loss, cell failure, and fire. The application of stack pressure has been found to mitigate dendrite growth to an extent; however, the impacts of long-term pressure application on lithium deposition, and subsequent lithium plastic deformation and creep, are not well understood. In this work, we present a novel method for accurately modeling the interplay between mechanical deformation and electrochemical deposition. We develop a 3D, finite-element, transient model of lithium plating and stripping at the mesoscale. A stack pressure is applied to a lithium anode in contact with a polymer separator, and the electrochemical response to an applied current density is evaluated. The lithium protrusion is then reshaped to model incremental plating or stripping, thus simulating the cumulative interfacial movement over a full charge-discharge cycle. Mechanical complexities of the materials, such as lithium plastic deformation and separator porosity, are accounted for. The interfacial response is studied with respect to applied stack pressure and assumed lithium yield strength. Through this work, the impacts of stack pressure on dendrite growth at the microscale are explored. The lithium yield strength assumption is found to be crucial for accurately predicting deposition behavior.
Supported by the Laboratory Directed Research and Development program at Sandia National Laboratories, a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525.
(Invited) Tuning the Optoelectronic Properties of Inorganic and Carbon-Based Quantum Dots for Highly Efficient Luminescent Solar Concentrators
Authors: Ibrahim Kassa Belay , Hassan Mahnoor , Shifa Tofik Ahmed , Vomiero Alberto 
Published: August 2024

Luminescent solar concentrators (LSCs) are an old class of devices based on semitransparent windows, in which luminophores are embedded in a transparent matrix.[1] The luminophores can absorb and re-emit solar light and are able to generate electric power by collecting the re-emitted light at the borders of the slab. In the past, lab-to-fab transition of such devices was impeded by intrinsic limitations of the luminophores in terms of low quantum yield, strong resorption due to small Stokes shift, low optical and photoconversion efficiency of the final device. In the last years, a renaissance of such devices has been driven by the development of new 0-dimensional nanostructures, with tunable optical properties, which can guarantee good performance of LSCs.[2,3] Specifically, high quantum yield can be obtained; resorption losses can be limited by modulating the Stokes shift; final color of the window can be tuned by tuning light absorption properties; UV and IR parts of solar spectrum can be exploited without affecting window transparency. We will give examples of different 0-dimensional systems, which have been developed toward high efficiency LSCs, among which inorganic quantum dots and carbon dots.[4,5] Several strategies will be illustrated to tune the optoelectronic properties of the luminophores, including doping, core-shell structuring, and surface treatments.
References
[1] R. Mazzaro, A. Vomiero. Advanced Energy Materials, 2018, 8 (33), 1801903.
[2] Y. Zhou et al. Advanced Energy Materials, 2016, 6 (11), 1501913.
[3] H. Zhao et al. Energy & Environmental Science, 2021, 14 (1), 396-406.
[4] X. Gong et al. Materials Chemistry Frontiers, 2021, 5 (12), 4746-4755.
[5] G. Liu et al. Journal of Materials Chemistry A, 2023, 11 (16), 8950-8960.
(Invited) Colloidal Quantum Dot Laser Diodes: Three Decades in the Making
Authors: Klimov Victor I. 
Published: August 2024

It has been 30 years since the first demonstration of lasing with semiconductor nanocrystals embedded in glass matrices1 – the samples akin to standard colored glass filters. Following this discovery, it took three years to realize lasing with epitaxial QDs2 and six more years to demonstrate the effect of amplified spontaneous emission (ASE) – a precursor of lasing – with colloidal QDs.3

So far, all reported studies into colloidal QD lasing have utilized optically excited samples. However, most of the prospective technological applications require electrically pumped devices, that is, laser diodes. The realization of such devices is complicated by multiple problems, widely deemed insurmountable. These include extremely fast nonradiative Auger recombination of optical-gain-active multicarrier states, poor stability of QD films under high current densities required for lasing, and unfavorable balance between optical gain and optical losses in electroluminescent (EL) devices wherein a gain-active QD medium is a small fraction of an overall device stack comprising multiple optically lossy charge-transport layers.
Here we resolve these problems and achieve strong ASE with electrically driven QDs.4 To demonstrate this effect, we employ compact, continuously graded QDs with strongly suppressed Auger recombination incorporated into a low-loss photonic waveguide integrated into a pulsed light-emitting diode capable of operating at current densities of up to ~2000 A cm-2. These prototype ASE-type laser diodes exhibit strong, broad-band optical gain and demonstrate low-threshold, room-temperature ASE which leads to intense, edge-emitted EL whose instantaneous power reaches ~200 mW.
1. Vandyshev, Y. V., Dneprovskii, V. S., Klimov, V. I. & Okorokov, D. K. Lasing on a transition between quantum-well levels in a quantum dot. JETP Lett.
54, 442-445 (1991).
2. Kistaedter, N., Ledentsov, N. N., Grundmann, M., Bimberg, D., Ustinov, V. M., Ruvimov, S. S., Maximov, M. V., Kopev, P. S., Alferov, Z. I. & Richter, U. Low threshold, large To injection laser emission from (InGa)As quantum dots. Electron. Lett.
30, 1416 (1994).
3. Klimov, V. I., Mikhailovsky, A. A., Xu, S., Malko, A., Hollingsworth, J. A., Leatherdale, C. A., Eisler, H. J. & Bawendi, M. G. Optical gain and stimulated emission in nanocrystal quantum dots. Science
290, 314-317 (2000).
4. Ahn, N., Livache, C., Pinchetti, V., Jung, H., Jin, H., Hahm, D., Park, Y.-S. & Klimov, V. I. Electrically driven amplified spontaneous emission from colloidal quantum dots. Nature
617, 79-85 (2023).
(Invited) Photoluminescence Properties of Single InAsP Quantum Dots Embedded in InP Nanowires
Authors: Haffouz Sofiane , Poole Philip J , Northeast David , Williams Robin L. , Dalacu Dan 
Published: August 2024

Non-classical light emitters that can generate single photons with a negligible multiphoton probability are one of the key components for quantum information technologies. Deterministically grown III-V semiconductor nanowires containing quantum dots are gaining interest as a viable platform for quantum key distribution applications. In this talk, we will report on our recent development of the fabrication of InAsP single quantum dots embedded within InP photonic waveguide nanowires. In particular, we outline the importance of the photonic waveguide design for optimum photon generation and coupling to external optics [1]. The measured count rate dependence on normalized wire diameter, D/λ (figure 1) of the nanowire sources is consistent with calculations of the spontaneous emission rate into the fundamental HE11 nanowire waveguide mode (ΓHE11). Manipulating dot growth conditions and engineering the band structure around the dot (dot-in-a-rod configuration) are applied [2] to enhance the photoluminescence emission rate at 1310 nm and 1550 nm. Single photon emission with very low multiple photon probability is demonstrated at O- and C-band [3,4]. Temperature dependent, second-order correlation measurements on the 1310 nm source show that these nanowire sources can generate single photons up to temperatures of 220 K [3].
[1] S. Haffouz, et al., Nano Letters, 18, 3047 (2018).
[2] S. Haffouz, et al., Applied Physics Letters, 117, 113101 (2020).
[3] P. Laferriére, et al., Nano Letters, 23, 962 (2023).
[4] A.N. Wakileh, et al., arXiv:2309.13381 (2023).

Figure 1
(Dielectric Science & Technology Thomas Callinan Award) Rare-Earth Luminescence in Silicon-Based Thin Film Structures
Authors: Azmi Fahmida , Khatami Zahra , Mascher Peter 
Published: August 2024

For Si-based materials to be used in solid-state lighting and silicon photonics schemes it is necessary to have precise control of the optical emission from these materials. This can be accomplished using rare earth dopants such as Ce, Tb, and Eu to obtain blue, green, and red emissions, respectively. In this talk, we first will provide a review of our work in this field and then focus on Eu-doped films, which are particularly attractive for silicon photonic applications due to their intense emission in the visible spectral region [1]. We will also discuss the benefits of introducing a novel hybrid radio frequency (RF) magnetron sputtering source in the electron cyclotron resonance (ECR) plasma enhanced chemical vapour deposition (PECVD) reactor chamber [2], using the example of Tb-doped SiON films [3]. This approach contrasts with traditional doping methods which use metal-organic precursors or ion implantation to introduce rare-earth dopant species into the host matrix.
[1] F. Azmi et al., “Tunable Emission from Eu:SiOxNy Thin Films Prepared by Integrated Magnetron Sputtering and Plasma Enhanced Chemical Vapor Deposition”, J. Vac. Sci. Technol. A 40, 043402 (2022); DOI: 10.1116/6.0001761
[2] J.W. Miller et al., “Integrated ECR-PECVD and Magnetron Sputtering System for Rare-Earth-Doped Si-Based Materials”, Surface and Coatings Technology 336, 99 (2018); DOI: 10.1016/j.surfcoat.2017.08.051
[3] Z. Khatami et al., "A comprehensive calibration of integrated magnetron sputtering and plasma enhanced chemical vapor deposition for rare-earth doped thin films", J. Mater. Res. (2023); DOI: 10.1557/s43578-023-01207-2