bluuebunny/crossref_metadata_2025 huggingface dataset:
On-Surface Synthesis of Fused Anthracenyl Porphyrin Derivatives
Authors: Pijeat Joffrey , Baljozovic Milos , Lamare Raphael , Ernst Karl-Heinz , Campidelli Stephane
Published: July 2022

For the last fifteen years, on-surface synthesis became an extremely popular and powerful method to fabricate nanostructures which otherwise would not have been accessible by conventional wet organic syntheses. The syntheses, realized in the chamber of high vacuum scanning tunneling microscope (STM), permitted the fabrication and the characterization of atomically defined nanostructures such as polycyclic aromatic hydrocarbons (PAH), graphene nanoribbons or 2D covalent networks.1 Among the organic molecules studied by STM, porphyrins are of particular importance because of their electronic and optical properties. Initial studies were mainly devoted to the supramolecular organization of porphyrins and porphyrin derivatives on surface and it is only in 2004 that noble metal surfaces were used as catalytic surface to perform reactions on the porphyrin cores.2 Since then, examples of open-shell porphyrin derivatives3 and conjugated oligomers4 were reported.

While the synthesis of fused bis- and tetra-4,5-bis-(2,4,6-trimethylphenoxy)anthracen-9-yl porphyrins containing Ni(II) was reported by Anderson about 10 years ago,5 the formation π-extended porphyrin bearing unsubstituted anthracenyl moieties were never achieved. The formation of such compounds became possible by on-surface synthesis. Herein, we report on the synthesis of fused bis- and tetra-anthracenylporphyrin derivatives via the cyclodehydrogenation the parent meso-substituted molecules on a catalytic Au(111) surface.6 Depending on the annealing temperature, anthracenylporphyrins with the four anthracene fully linked to the porphyrin core or over-oxidized porphyrin in which the anthracene are connected two by two in 2-2’ position were observed by STM (Figure 1).

Figure 1. STM images of the fused tetra-anthracenylporphyrins and related porphyrin structures

References

Clair, S.; de Oteyza, D. G. Chem. Rev.
2019, 119, 4717-4776.

Fox, S.; Boyle, R. W. Chem. Commun.
2004, 1322-1323.

a) Sun, Q.; Mateo, L. M.; Robles, R.; Ruffieux, P.; Lorente, N.; Bottari, G.; Torres, T.; Fasel, R. J. Am. Chem. Soc.
2020, 142, 18109-18117; b) Zhao, Y.; Jiang, K.; Li, C.; Liu, Y.; Xu, C.; Zheng, W.; Guan, D.; Li, Y.; Zheng, H.; Liu, C.; Luo, W.; Jia, J.; Zhuang, X.; Wang, S. J. Am. Chem. Soc.
2020, 142, 18532-18540.

a) Mateo, L. M.; Sun, Q.; Liu, S.-X.; Bergkamp, J. J.; Eimre, K.; Pignedoli, C. A.; Ruffieux, P.; Decurtins, S.; Bottari, G.; Fasel, R.; Torres, T. Angew. Chem., Int. Ed.
2020, 59, 1334-1339; b) Mateo, L. M.; Sun, Q.; Eimre, K.; Pignedoli, C. A.; Torres, T.; Fasel, R.; Bottari, G. Chem. Sci.
2021, 12, 247-252.

a) Davis, N. K. S.; Thompson, A. L.; Anderson, H. L. Org. Lett.
2010, 12, 2124-2127; b) Davis, N. K. S.; Thompson, A. L.; Anderson, H. L. J. Am. Chem. Soc.
2011, 133, 30-31.

Baljozović, M. et al., in preparation

Figure 1
Recent Advances in Zinc Anc Cooper Phthalocyanines As Hole Transporting Materials in Perovskite Solar Cells
Authors: Sastre-Santos Angela
Published: July 2022

Recently, significant progresses have been achieved in the fabrication of highly efficient perovskite solar cells, while major challenges, such as commercial viablity of exotic materials and their instability, remain as an obstacle. Hole transporting materials (HTMs) represent a tricky choice for the fabrication of efficient solar cells and the cost uneffective Spiro-OMeTAD continue to be so far the most obvious candidate. Semiconductors molecules, such as metallophthalocyanines (MPcs)1 appeared as a promising class of p-type material, since they are less expensive and more stable.

In this communication, we will present the synthesis of novel ZnPcs,2 ZnPc dimers3 and CuPcs4 (see as examples Figure 1) as efficient, stable, and low cost HTMs in PSCs. The MPcs are substituted with functional groups that possesses a very good solubility in a wide range of organic solvents, adequate HOMO LUMO levels and thus can be applied from solution processing in a wide range of perovskite solar cell devices.

Figure 1. Different ZnPcs structures as HTMs in PSCs

References

M. Urbani, M. E. Ragoussi, M. K. Nazeeruddin, T. Torres, Coord. Chem. Rev.
2019, 381, 1-64.

P. Huang, A. Hernández, S. Kazim, J. Ortíz, Á. Sastre-Santos, S. Ahmad Sustainable Energy &Fuels.
2020, 4, 6188-6195.

a) D. Molina, M. A. Ruiz-Preciado, F. Sadegh, M. João Álvaro-Martins, M. Grätzel, A. Hagfeldt, Á. Sastre-Santos, J. Porphyr. Phthalocyanines, 2019, 23, 546–553. b) D. Molina, M. A. Ruiz‐Preciado, B. Carlsen, F. T. Eickemeyer, B. Yang, N. Flores‐Díaz, M. J. Álvaro‐Martins, K. Nonomura, A. Hagfeldt and Á. Sastre‐Santos, ChemPhotoChem, 2020, 4, 307–314.

a) L. Caliò, J. Follana-Berná, S. Kazim, M. Madsen, H. G. Rubahn, Á. Sastre-Santos, S. Ahmad, Sustainable Energy Fuels, 2017, 1, 2071-2077. b) P. Huang, A. Hernández, J. Follana-Berná, S. Kazim, J. Ortíz, Á. Sastre-Santos, S. Ahmad, ACS Appl. Energy Mater.
2021, 4, 9, 10124–10135

Figure 1
Phosphorus(V) Porphyrin: A Reductive Electron Quencher in Donor-Acceptor Systems
Authors: Poddutoori Prashanth , Zarrabi Niloofar , Bayard Brandon J , Holzer Noah , Seetharaman Sairaman , Karr Paul , D'Souza Francis , van der Est Art
Published: July 2022

Phosphorus(V) porphyrins hold an important place in porphyrin chemistry. The hexacoordinated phosphorus center in these porphyrins has a formal oxidation state of +5 and is, thus, extremely electron deficient. As a result, the midpoint potential for oxidation of the phosphorus(V) porphyrin is shifted to a much higher value (1.66 V for PTPP+) compared to the corresponding free-base porphyrin (1.01 V for H2TPP) or zinc(II) porphyrin (0.79 V for ZnTPP). In addition, the phosphorus center provides two axial sites for the covalently binding of substituents, allowing a greater range of possibilities for attaching donors and acceptors. By exploiting these properties several ‘axial-bonding’ type Donor-Acceptor systems have been prepared consisting of octaethylporphyrinatophosphorus(V) (POEP+) and tertaphenylporphyrinatophosphorus(V) (PTPP+) units. The unique structural topology of the octaethylporphyrinatophosphorus(V) (POEP+) and tertaphenylporphyrinatophosphorus(V) (PTPP+) enabled the construction of mono- and di-substituted phosphorus(V) porphyrin-naphthalene conjugates, respectively. Transient absorption studies revealed rapid deactivation of singlet excited phosphorus(V) porphyrin due to the reductive electron transfer process. I will present some of these examples and discuss their structural, redox, and photophysical properties.

Figure 1
C3N4 and C3N5 Nanosheets As Passivation Layers and Carrier Extractors for Inorganic Semiconductor Nanowires and Quantum Dots
Authors: Alam Kazi , Kumar Pawan , Laishram Devika , Jensen Charles , Degg Annabelle , Chaulagain Narendra , Hegmann Frank , Nilges Tom , Sharma Rakesh , Shankar Karthik
Published: July 2022

Inorganic semiconductor nanowires and quantum dots made of chalcogenides, III-V semiconductors and halide perovskites offer exciting potential for optoelectronic devices. The orthogonalization possible in nanowires between the normally competing processes of charge generation and charge separation have been used to project very high operating performance exceeding that of thin films and single crystals in light harvesting devices such as solar cells, photodetectors, photocatalysts and photoelectrolyzers. Likewise, inorganic quantum dots with size-tunable absorption and emission spectra are excellent candidates for light emitting devices as well as light harvesting devices. However, the practical performance of inorganic nanowire based optoelectronic devices has significantly lagged theoretical predictions. A major reason for the discrepancy between theory and experiment is the presence of surface traps and defects in nanowires and quantum dots, which exhibit a large surface area to volume ratio. Several chemical treatments and annealing regimens have been employed to heal surface defects in nanowires and quantum dots. One popular strategy involves wrapping nanowires and/or quantum dots with a thin coating of a molecular monolayer (e.g. alkanethiols) or an atomic layer deposited conformal oxide. While such core-shell architectures are frequently effective in reducing surface defects, the surface passivation is invariably accompanied by a deterioration in optoelectronic properties due to the difficulty experienced by charge carriers in tunneling through the thin shell layer. The resulting trade-off between surface passivation and carrier extraction limits performance improvements in light harvesting devices. Thus there is a strong need for passivating layers that do not negatively impact carrier extraction.

Herein, we show that graphitic carbon nitride coatings are highly effective in passivating the surfaces of inorganic nanowires and quantum dots while preserving excellent carrier transport and extraction. Three illustrative examples are provided together with in-depth spectroscopic and electrical characterization:

(1) Cesium lead bromide (CsPbBr3) quantum dots passivated by g-C3N4 nanosheets and performing spectacularly as CO2 photoreduction catalysts and water-splitting photoanodes

(2) The double helical ternary semiconductor SnIP passivated by g-C3N4 nanosheets which experienced a remarkable improvement in photoelectrochemical performance

(3) Cadmium sulfide (CdS) nanowires passivated by C3N5 nanosheets resulting in a superior photocatalytic performance
(Digital Presentation)Room Temperature Sensor Using Dielectrophoretic Trapping of Carbon Nanotubes
Authors: Ghomian Taher , Burdette Kaylee , Farimand Samaneh , Hihath Josh
Published: July 2022

This abstract presents the design and fabrication of a temperature sensor based on carbon nanotubes (CNTs). The sensor is fabricated by dielectrophoretic trapping of CNTs between two nanoelectrodes. The conductance of the sensor is highly sensitive to the temperature variation which makes it suitable for applications requiring accurate measurements. In addition, fast response and good stability and durability are the important advantages of the sensors made of CNTs.

The structure of the device is shown in the figure. CNTs are trapped in between nanoelectrodes using the dielectrophoresis (DEP) technique. Dielectrophoresis is a phenomenon in which a force is applied to a dielectric particle when it is exposed to a non-uniform electric field [1]. Although dielectrophoresis provides an accurate method for trapping materials in a predefined area, this method suffers from a costly fabrication process when dealing with nanomaterials. In this study, we used a standard photolithography method to fabricate low-cost devices and an electronic circuit is used to apply the required electric field and monitor the gap for the presence of CNTs.

The device fabrication process starts with the patterning and depositing gold nanoelectrodes and contacts using the photolithography method. The process is followed by converting the surface of the device except for the nanoelectrodes area and connection pads with an insulation layer of Silicon nitride. Since the electrodes are thin (50 nm) and CNTs are flexible, fabrication on the flexible substrates is also feasible.

References

[1] T. Ghomian et al., "High‐Throughput Dielectrophoretic Trapping and Detection of DNA Origami," Advanced Materials Interfaces, vol. 8, no. 5, p. 2001476, 2021.

Figure 1
Bulk Heterojunction Solar Cells: Porphyrins, Dpps and Bodipys As Building Blocks for Efficient Donor Materials
Authors: Gros Claude , Bucher Léo , Desbois Nicolas , Sharma Ganesh D
Published: July 2022

Among the different types of organic semiconducting materials, porphyrins, DPPs and BODIPYs based small molecules and conjugated polymers have attracted high interest as efficient semiconducting organic materials for dye sensitized solar cells (DSSC) and bulk heterojunction (BHJ) organic solar cells. Interestingly, they offer a synergistic effect when used together within a material, this coming from high complementarities of their absorption spectra, adapted prerequisites in order to be efficient energy transfer partners, and suitable frontier orbitals energy levels. We have recently designed different porphyrins, DPPs and BODIPYs based electron donor small molecules/polymers for bulk heterojunction organic solar cells (Figure), and now report their synthesis as well as the study of their electrochemical, photophysical and photovoltaic properties.

The “Consulat Général de France à Québec” and the “Programme Samuel de Champlain 2015/2016” are acknowledged for funding. We are thankful to Prof. P. D. Harvey (Université de Sherbrooke, CA) for PhD co-supervising and photophysical measurements.

REFERENCES

Bucher, L.; Desbois, N.; Harvey, P. D.; Sharma, G. D.; Gros, C. P., Solar RRL
2017, 1 (12), 1700127.

Bucher, L.; Tanguy, L.; Fortin, D.; Desbois, N.; Harvey, P. D.; Sharma, G. D.; Gros, C. P., ChemPlusChem
2017, 82, 625-630 (Biofest special issue).

Bucher, L.; Desbois, N.; Harvey, P. D.; Gros, C. P.; Sharma, G. D., ACS Appl. Mater. Interfaces
2018, 10 (1), 992-1004.

Bucher, L.; Tanguy, L.; Desbois, N.; Karsenti, P.-L.; Harvey, P. D.; Gros, C. P.; Sharma, G. D., Solar RRL
2018, 2 (1), 1700168.

Figure 1
(Digital Presentation) The Photoresponse Enhancement of Graphene Photodetector By Metasurface Under Mid-Infrared Region
Authors: Lin Kuan-Chou , Lin Chih-Ting
Published: July 2022

As a zero bandgap material, graphene has excellent optical properties and electrical doping characteristics. Graphene plasmons exhibit much larger confinement and longer propagation distances than noble-metal plasmons. The surface plasmons technique has been widely used in photodetectors because it can couple light to the devices for signal detection. In this paper, we combine graphene with existing surface-plasmon-based devices and show that the photocurrent is twice as intrinsic graphene devices under the same infrared light source. Metasurface on graphene/SiO2 under infrared light will induce plasmon–phonon quasi-particle, which will decay into electron-hole pairs and phonons. The former increases the total transport current and dominates in the graphene lightly doping condition. The latter decreases the total transport current and dominates in the graphene highly doping condition. As a result, the responsivity can be tailored by Fermi-level tuning. We demonstrate that the responsivity of the metasurface graphene photodetector can reach the ~5e-4 A/W in the mid-infrared region. It's believed that the high responsivity and photoresponse modulation has promising and flexible application scenarios in photodetectors.
Conversion of Meso-Aryl Substituted Open-Chain Pentapyrroles to Sapphyrins: Synthesis and Electrochemistry
Authors: Desbois Nicolas , Pacquelet Sandrine , Rousselin Yoann , Shan Wenqian , Kadish Karl M. , Gros Claude
Published: July 2022

Sapphyrin is a 22-π aromatic pentapyrrolic macrocycle containing one direct link and four bridging methine groups between five pyrrole subunits.1 This macrocycle is an early member of the group of “expanded porphyrins” and was obtained from a pentapyrrole, a byproduct in the synthesis of corroles. A series of open-chain pentapyrroles and sapphyrins with meso-tetraaryl groups were synthesized (Figure 1) and are characterized as to their electrochemistry and protonation reactions in nonaqueous media.2 The protonation-initiated conversion of pentapyrroles to sapphyrins upon oxidation was investigated and cyclic voltammetry was used to measure the redox potentials in CH2Cl2, PhCN, and/or pyridine (Py).

REFERENCES

1. V. J. Bauer, D. L. J. Clive, D. Dolphin, J. B. Paine, F. L. Harris, M. M. King, J. Loder, S. W. C. Wang, R. B. Woodward, J. Am. Chem. Soc. 1983, 105,6429-6436.

2. W. Shan, N. Desbois, V. Blondeau-Patissier, M. L. Naitana, V. Quesneau, C. P. Gros, Y. Rousselin, W. Huang, Z. Ou, K. M. Kadish, Chem. Eur. J.,
2017
, 23, 12833-12844.

Figure 1

Figure 1
Prussian Blue Analogues for Potassium-Ion Batteries: Application of Complementary Operando X-Ray Techniques
Authors: Le Pham Phuong Nam , Wernert Romain , Aquilanti Giuliana , Johansson Patrik , Monconduit Laure , Stievano Lorenzo
Published: July 2022

In the last 5 years, potassium-ion batteries (PIBs) have been considered as a promising post-lithium-ion battery technology, much due to cost effectiveness and a variety of electrode materials available [1]. Prussian Blue Analogues (PBAs), with advantages such as simple synthesis, high capacity, and eco-friendliness, have gained a huge interest [2–4] and here we present a detailed study on the electrochemical mechanism of K
x
Mn2/3Fe1/3[Fe(CN)6]
y
.zH2O. We do this by combining complementary operando techniques: X-ray diffraction and X-ray absorption spectroscopy, supported by ex situ
57Fe Mössbauer spectroscopy. Chemometric analysis of the operando data allows us to follow the physico-chemical and structural evolution during electrochemical cycling, providing deeper understanding. From this, a reversible phase transition between monoclinic and cubic crystal structure was observed during the oxidation/reduction of Mn species. The local geometry information on Fe and especially Mn, as obtained from the EXAFS data analysis, serves to explain the volume expansion of the Fe–CN–M (M = Mn, Fe) framework during the extraction of potassium. This paves the way for optimizing the PBA composition for PIB application.

References

[1] T. Hosaka, K. Kubota, A.S. Hameed, S. Komaba, Research Development on K-Ion Batteries, Chem. Rev. 120 (2020) 6358–6466. https://doi.org/10.1021/acs.chemrev.9b00463.

[2] X. Jiang, T. Zhang, L. Yang, G. Li, J.Y. Lee, A Fe/Mn-Based Prussian Blue Analogue as a K-Rich Cathode Material for Potassium-Ion Batteries, ChemElectroChem. 4 (2017) 2237–2242. https://doi.org/10.1002/celc.201700410.

[3] A. Zhou, W. Cheng, W. Wang, Q. Zhao, J. Xie, W. Zhang, H. Gao, L. Xue, J. Li, Hexacyanoferrate-Type Prussian Blue Analogs: Principles and Advances Toward High-Performance Sodium and Potassium Ion Batteries, Adv. Energy Mater. 11 (2021) 1–35. https://doi.org/10.1002/aenm.202000943.

[4] K. Hurlbutt, S. Wheeler, I. Capone, M. Pasta, Prussian Blue Analogs as Battery Materials, Joule. 2 (2018) 1950–1960. https://doi.org/10.1016/j.joule.2018.07.017.
(Digital Presentation) Predicting Hydrogen Diffusivity in Amorphous Titania Using Markov Chain Kinetic Monte Carlo Simulations
Authors: Chapman James , Kweon Kyoung E. , Goldman Nir , Keilbart Nathan Daniel , Heo Tae Wook , Wood Brandon C.
Published: July 2022

Understanding hydrogen transport is vital to industries focused on discovering new materials for energy storage and corrosion mitigation. However, knowledge of the physical nature of hydrogen’s diffusion pathways is often limited, especially for materials that exhibit a multitude of phases/defect classes. These materials typically have three rate-limiting structural domains: (1) bulk (2) grain boundaries, and (3) surfaces. In this work we have chosen to study hydrogen diffusion through titania due to its importance in the aforementioned application spaces. Here, we aim to understand diffusion through titania grain boundaries, which are approximated via the amorphous phase. Density functional theory (DFT) was used to calculate thousands of activation energies of hydrogen diffusion in the amorphous phase via nudged elastic band calculations using an automated hydrogen pathway generation scheme. Amorphous structures, on the order of tens of nanometers, were generated using a machine learning force field via classical molecular dynamics (MD). Markov chains were generated using the MD-derived atomic structures as their reference. Kinetic Monte Carlo (KMC) simulations were then performed over a variety of temperatures and stoichiometries, for system sizes in the tens of nanometers, allowing us to connect directly with experimental measurements. Using our KMC simulations we can directly calculate the hydrogen diffusion constant, as a function of temperature and stoichiometry, and compare these values with those determined via experiments. We also employ a graph-based characterization scheme that can quantify the subtle differences in local hydrogen diffusion networks throughout the KMC simulation, allowing us to link local hydrogen diffusivity with structural differences within the material observed along the diffusion pathway. This work sets the stage for one to perform long time-scale and/or length-scale simulations to understand how temperature and atomic structure affect properties such as diffusivity, solubility, and permeation, and connect these values directly with experiments.
(Digital Presentation) Understanding Metal Additive Manufactured Surfaces
Authors: Stull Jamie A , Gorey Timothy , Clark Courtney L , Hooks Daniel E
Published: July 2022

Metal additive manufacturing (AM) is being pursued as manufacturing technique in order to shorten development cycles and reduce cost through rapid iteration and agile design. Metal AM allows for designs that were not previously possible, optimizing the balance between mechanical strength and weight. However, rough as-built surfaces do not meet engineering specifications, with roughness measurements between Sa = 5 – 60 mm. Furthermore, depending on the build angle the surface roughness varies widely within a single part. These rough surfaces result in different surface morphology and chemistry compared to other manufacturing methods which has a direct impact on the susceptibility to localized corrosion and mechanical performance. This variation is also amplified depending on the machine used to build the material. We have extensively characterized the surface roughness, and corrosion response of AM 316L stainless steel (SS) that has been built on different machines which result in significantly different surface properties.

Our team is also developing environmentally friendly surface finishing techniques to reduce the surface roughness to meet specifications, increase corrosion performance, and drastically reduce the part-to-part variations. We have used optical methods to measure the surface roughness of as-built AM 316L SS, A20x (AM aluminum alloy), and Ti6-4. Aqueous and atmospheric corrosion measurements have been performed on 316L SS. Finally, EDS/SEM measurements reveal there is significant chemical segregation on the surface of the as-built material; however, surface treatment methods being developed by the group have been shown to remove this layer. Post-processing surface treatments result in a more homogeneous surface and improve the performance of the material.
(Digital Presentation) Effects of Surface Finish on the Corrosion Performance of Additively Manufactured Metals
Authors: Clark Courtney L , Stull Jamie A , Gorey Timothy , Hooks Daniel E
Published: July 2022

Metal additive manufacturing (AM) is becoming a transformative technology in the manufacturing industry. The as-built surfaces produced by metal AM are very different compared to wrought material, typically resulting in very rough surfaces that have different corrosion properties. There are a large number of studies that have attempted to understand the corrosion response of metal AM. However, these studies are typically performed on materials that have been printed on a single machine. As a result, there are significant inconsistencies in the literature due to the high variability in the quality of parts manufactured on different machines. We will present work that compares the corrosion response of AM 316L stainless steel (SS) that has been printed on multiple machines. Our results have shown there is significant variability observed in the corrosion performance of metal AM parts built on different machines and within a single build plate. The observed corrosion performance is likely affected by the stability of the passive film, chemical segregation, and microstructure of the surface. We also propose that surface finishing of AM 316L SS reduces the part-to-part variations observed in the corrosion performance of the material printed on different machines and within a single build plate.

This talk will discuss the corrosion properties of AM 316L SS, A20x (AM aluminum alloy), and Ti-6Al-4V parts produced by direct metal laser sintering (DMLS). The majority of our work focused on understanding the susceptibility to localized corrosion of metal additively manufactured materials with respect to build machine, surface roughness, and build angle. As a result, we also examined the corrosion performance of 316L SS built on a single instrument as we varied the build parameters. Conventional electrochemical corrosion experiments were used to characterize corrosion performance, including open circuit potential, potentiostatic electrochemical impedance spectroscopy, and potentiodynamic polarization scans. White light interferometry, optical profilometry, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were utilized to characterize the surface of the samples.
Corrosion-Resistant Sacrificial Metallic Coatings Produced By Cold-Spray for Al Alloys
Authors: Witharamage Chathuranga S , Alrizqi Mohammed A , Darwish Ahmed A , Nieto Andy , Gupta Rajeev Kumar
Published: July 2022

Corrosion is a massive disaster in many sectors that caused the loss of billions of dollars. For example, it was reported that the total direct estimated cost of corrosion was about $ 276 billion in 1998 in the US, which is 3.1% of the nation’s GDP. Therefore, a necessity to develop methods to overcome this challenge arose in the last few decades. Thus, the development of corrosion resistive coatings is significantly attracted researchers' attention. In combination with the corrosion inhibitors, organic and conversion coatings are used to improve the corrosion resistance of high-strength Al alloys. However, many corrosion inhibitors are carcinogenic: Chromate conversion coating performed very well, but alternative options need to be explored due to restrictions on its applications due to the health and environmental regulations. Moreover, organic coatings provide good corrosion resistance, but poor wear resistance and mechanical damage lead to corrosion issues. Metallic coatings are an alternative, and galvanized steel is one of the prominent examples. However, metallic coatings produced by elements such as Cr, Ni, Ti, or Ta are noble for Al or Mg-based alloys. Therefore, in any event of coating breakdown, the substrate would be more active and act as an anode and, corrode rapidly by galvanic interaction. Thus, such metallic coatings produced by the above-mentioned corrosion resistance elements are not very attractive for Al alloys.

We present a sacrificial metallic coating with outstanding corrosion resistance. Al was alloyed with V using high-energy ball milling (HEBM) which enabled the formation of a superstrated solid solution of V in Al. Al-V alloy powder produced by HEBM was used for coating the high-strength substrate using cold spray. The corrosion behavior and corrosion mechanisms of cold sprayed specimens were investigated using advanced electrochemical and analytical techniques. The cold sprayed specimens exhibit high pitting potential, low corrosion current density, and a less noble corrosion potential than the substrate. This indicates that in any event of coating breakdown, the coating would corrode (i.e., act as a sacrificial anode) and prevent the substrate from corrosion. Alloy composition is chosen such that corrosion of coating releases chemical species that could inhibit corrosion by decreasing the cathodic efficiency of the substrate.
Corrosion of Secondary Hpdc A365 (AlSi10MnMg(Fe)) Alloys for Automotive Applications
Authors: Ando Yuki , Feenstra Darren , Shankar Sumanth , Kish Joey
Published: July 2022

Al alloys with suitable mechanical properties and castability are widely used for thin-wall structural HPDC components with complex shapes. Al alloy A365 (9-11.5% Si, 0.4-0.8%Mn, 0.1-0.6% Mg, 0.25% Fe max.) is typically produced using primary Al (raw material) to control/minimize the impurity Fe content. Secondary A365, made using recycled end-of-life material, with equivalent mechanical properties as the primary alloy, provides an opportunity to reduce life cycle greenhouse gas (GHG) emissions from light-duty vehicles through improved end-of-life material recovery. The primary alloy is susceptible to micro-galvanic corrosion, where the eutectic a-Al phase serves as the anode and the eutectic Si phase, and incorporated secondary intermetallic phases serves as the cathode. The purpose of this work is to determine the extent to which utilization of end-of-life materials alters the microstructure and, in turn, corrosion (anode and cathode kinetics) of secondary A365, as revealed by electrochemical measurements.
Scanning Micropipette Contract Method Measurement of Aluminum Alloy: Effect of Approach Parameters on Corrosion Potential
Authors: Li Yuanjiao , Mauzeroll Janine
Published: July 2022

Scanning electrochemical cell microscopy (SECCM) enables direct electrochemical measurements at microscopic sits by scanning a droplet cell over a substrate surface. Scanning micropipette contact method (SMCM) is a type of single-channel SECCM. It has been used to record the spatially resolved electrochemical activities across metal surfaces to investigate corrosion at the (sub)microscale. In SMCM, the applied potential during the approach of micropipette to the substrate (Eappr), generates a transient current upon droplet contact with the substrate. Once the transient current exceeds a set threshold, the micropipette is automatically halted. In the investigation of aluminum alloy, we found that Eappr affected the subsequent measurements of corrosion potential (Ecorr) in the open circuit potential (OCP) and potentiodynamic polarization (PDP), which was considered to be inconsequential previously. For aluminum alloys, the dense oxide film restricts the surface conductivity, increasing the difficulty of droplet landing. This leads to pipette-substrate contact and droplet-substrate contact landings using different Eappr. Additional oxygen flux from the droplet-oil interface in the droplet-substrate contact resulted in more positive Ecorr(OCP). In the anodic PDP at a high scan rate of 100 mV/s, Ecorr(PDP) moved away from Ecorr(OCP) to larger extent as Eappr increased to more cathodic values. The systematic interpretation of the effect of Eappr will promote the understanding of SMCM measurement especially in the field of metal corrosion.
(Digital Presentation) Effect of Zirconium Addition on the Corrosion Behavior of Binary Magnesium-Zirconium Alloys
Authors: Chen Yi-ting , Chu Peng-Wei
Published: July 2022

Magnesium (Mg) has the characteristics of low density and high specific strength, but its poor corrosion resistance is a fatal disadvantage. Therefore, various alloying elements are often added to Mg alloys to improve their properties. Among them, zirconium (Zr) is commonly added as a grain refiner for Mg alloys. However, in most cases, Zr was added as a secondary additive, by which the effect on the corrosion properties would be shadowed by other alloying elements. Therefore, this research aims to elucidate the effect of Zr addition on magnesium corrosion with two binary Mg-Zr alloys with different Zr concentrations (0.037wt% and 0.208wt%).

In this study, scanning electron microscope (SEM) with X-ray energy dispersive spectroscopy (EDS) was used to study the Zr distribution and compositional difference in the alloys. Scanning Kelvin probe force microscope (SKPFM) was used to reveal the Volta potential difference between the Zr particles and the Mg matrix. In situ optical microscopic (OM) observation combined with open circuit potential (OCP) monitor was used to record the alloy corrosion morphology evolution. And through electrochemical impedance spectroscopy (EIS) analysis, the difference in the alloy corrosion properties was investigated. Hydrogen evolution tests were used to quantify the corrosion rates.

Through SEM/EDS analysis, the size, distribution, and Fe content of the zirconium particles in the alloy are the most important differences between the two samples. For the sample with 0.208wt%Zr, the Zr particles are larger and contain more Fe. From SKPFM analysis, we also found that the Volta potential difference between the Zr particles and the Mg matrix is larger for the sample with higher Zr addition. Hydrogen evolution tests show that the corrosion rate of the 0.208wt%Zr sample is about 5 times compared to the 0.037wt%Zr sample, which is consistent with the EIS analysis results. The driving force of corrosion mainly comes from the microgalvanic effect provided by the Zr particles. The relationship between the Zr particles and localized corrosion behavior will also be discussed.

Figure 1
2D Materials Integrated CNT Hybrid Paper Electrodes for Flexible All-Solid-State Supercapacitors
Authors: Lonkar Sunil , Busa Chiara , AlTeneiji Mohamed
Published: July 2022

Flexible supercapacitors (SCs) have attracted growing interests as the power source for portable and wearable electronics. Carbon nanotubes (CNTs) are emerged as one of the promising materials for flexible SC electrodes due to their excellent high electrical conductivity, high mechanical strength, large surface area, and functionalization ability. CNTs can be assembled into several macroscopic forms based on the applications. In the present work, the CNT buckypapers integrated with 2D materials such as graphene and transition metal sulfides (TMDs) especially, tin sulfide (SnS2) nanoparticles were prepared using a simple mould casting method. The flexible and free-standing, interface-enhanced CNT paper having homogeneously dispersed 2D materials was prepared. The hybridized CNT papers were thoroughly characterized to elucidate their structural and surface properties. Finally, such hybrid CNT papers were used as binder-free, free-standing electrodes for the fabrication of flexible-all-solid-state supercapacitors. The electrochemical performance (CV, GCD, EIS) of the as obtained the symmetric and asymmetric devices were assessed to evaluate the charge storage performance and effect of 2D materials on the charge storage capability and stability were studied.

Figure 1
Effect of Supporting Anion for Copper Corrosion in Gas Diffusion Microenvironments
Authors: Thurman Kira A. , Kempler Paul A. , Boettcher Shannon W.
Published: July 2022

Copper is used in a variety of capacities in the development of renewable energy technologies, including as a catalyst on gas diffusion electrodes in electrochemical devices such as CO2 reduction devices. By gaining a better understanding of Cu corrosion, we can learn more about the durability of devices that utilize copper. However, there are a myriad of factors that influence the kinetics of metal corrosion and deposition, which increases the difficulty to precisely analyze the fundamentals. Factors of concern include adsorbing/desorbing multiple layers of metal, uneven surfaces, defects on the electrode surface, and changes in electrode crystal facets. To mitigate these factors, obtain a more representative picture of Cu corrosion, and investigate the effect of the anions on copper, we created three model systems by employing copper underpotential deposition (UPD) on a single-crystalline Au[111] surface: 1) a phenomenal model system in sulfuric acid; 2) a bridging environment (methane sulfonic acid); and 3) a model microenvironment for gas diffusion (Nafion electrolyte). As a result, a loss in peak sharpness, as well as an increase in the number of peaks that are less resolved were observed in phenomenal and bridging environment, respectively, and a loss in ordered monolayers was seen in model microenvironment. Surprisingly, sulfuric acid and methane sulfonic acid have similar charges passed indicating the same amount of copper is deposited and stripped, whereas much less charge is passed in Nafion, demonstrating that small changes to the supporting anion can have a large effect on Cu UPD structure. As the real world does not exist in a model system, our model microenvironment will provide a better image of Cu corrosion fundamentals in a gas diffusion electrode, which is critical for electrochemical devices application.

Figure 1
(Invited) Metrology of Solution Processable 2D Materials for Electronic Applications
Authors: Lopinski Gregory
Published: July 2022

Two-dimensional materials have attracted intense interest due to their remarkable physical and electronic properties as well as their potential for a diverse range of applications. Many of these envisaged applications (i.e. printed/flexible electronics, energy storage, photovoltaics) require single or few layer flakes of a 2D material that can be dispersed in solution to facilitate deposition onto a substrate, formulation into an ink and/or mixing into a composite. A variety of powders and dispersions claiming to contain 2D materials such as graphene are now becoming available but the variable quality of these materials and lack of standardized protocols for their assessment is hampering the development of applications.

Here we will describe ongoing work at the NRC aimed at developing characterization methods and standard protocols to characterize graphene and graphene oxide (GO) powders, dispersions and inks. We employ a variety of experimental techniques including scanned probe microscopies (AFM and STM), vibrational spectroscopy (Raman and FTIR), X-ray diffraction, X-ray photoelectron spectroscopy and dynamic light scattering in order to characterize the structure and chemical composition of in-house and commercially available materials. These methods allow us to measure key parameters to assess material quality such as flake thickness and lateral size, carbon to oxygen ratio and impurity content. Conductivity and work function of ultrathin films produced from various graphene and graphene oxide containing dispersions have been also measured. The performance of these films as transparent conductors can be characterized by a figure of merit based on the optical transmission and conductivity of the film. Performance of films made via reduction of GO will be compared with those based on graphene exfoliated without oxidation.

Recently we have begun to extend this work to dispersions of other two-dimensional materials such as the transition metal dichalcogenides (TMDC). Initial characterization of commercially available TMDCs will be presented.
Advancing Science and Technology of High-k Dielectric at ECS
Authors: Misra Durga
Published: July 2022

Historically SiO2 was the main driver as the transistor gate dielectric in CMOS technology. Once the thickness of SiO2 reached the onset of direct tunneling region (<1.5 nm) HfO2 -based high-k insulators were introduced to suppress the direct-tunneling leakage current. ECS started a symposium on Physics and Technology of High-k Gate Dielectrics in 2002 describing the evolution of dielectric science in nanoelectronics. In recent years transistor has transformed from a planar device to a three-dimensional device to a gate all around device. The electrical performance in these devices depends on the dielectric deposition process, precise selection of deposition parameters, pre-deposition surface treatments and subsequent thermal budget. By considering the interface reaction kinetics and thermal budget various atomic layer deposition (ALD) schemes were identified to get a stable dielectric with a robust interface. The deposition of Hf1-xZrxO2 on both silicon and germanium, a higher mobility channel material, were discussed. By doping HfO2 with ZrO2 and modifying the structural phase provides higher dielectric constant than the standard amorphous or monoclinic phase. Some of the reliability challenges of these dialectics based on dielectric-semiconductor interface were addressed and resolved. Several applications of high-k dielectrics have emerged including ferroelectric FETs and resistive random-access memory (ReRAM) devices that are being investigated for possible implementation of artificial intelligence hardware. Dr. Dolf Landheer presented his paper in the 1st symposium and from 2nd symposium onwards he was an organizer. He contributed significantly toward the advancing science and technology of high-k dielectrics and its dissemination for a long time in addition to other areas.
Detection of Proton Carriers in Tyrosine-Rich Peptide Thin Film
Authors: Yoon Jeong Hyun , Song Min-Kyu , Kwon Jang-Yeon
Published: July 2022

Traditional Von Neumann structure, where memory and computational units are separated, is now facing significant difficulties in terms of power consumption and computing speed in big data era. Therefore, human brain-like computing architecture is now paid attention in research field owing to its high parallelism, fault tolerance and robustness1-2. In this biological system, synaptic weight which plays crucial role in memory and learning is modulated by ionic species, especially protons transmitted between synapses. Here, we focused on short length peptide Y7C (YYACAYY) thin film which induces proton coupled electron transfer (PCET) due to its Tyrosine-rich structure. The Y7C film has shown an interesting behavior in which electrical conductivity varies with humidity3-4. By this modulation, bimodal memristor using both of voltage and humidity5 input and synaptic transistor which shows dynamic reponses through humidity have been demonstrated, but direct relation between current and proton conduction is still ambiguous. Therefore, we measured transient current flow between Pd and Au electrode and detected proton conduction of Y7C film.

In previous studies, voltage & humidity controlled Y7C bimodal memristor has been reported. However, since the current regulation through humidity showed insufficient response than that through voltage, a definite relationship between moisture and current needs to be defined. To achieve that, thin film of the peptide material dissolved in Trifluoroacetic acid (TFA) 99% solution was spin coated on SiO2/Si substrate. By measuring the transient current of the Y7C film, presence of temporary charge carriers was observed. Also, the electrical impedance spectroscopy (EIS) of peptide layer showed a semicircle and a nonvertical tail, which indicate ionic conduction through the film. Lastly, film characterization of Y7C thin layer unveiled that the corresponding ions are protons as originally targeted. This research has showed principles of peptide thin film’s current increment driven by both of humidity and voltage through electrochemical reaction.

Fig.1.
Transient charge flowing through Y7C thin film measured in various atmospheric conditions and electrodes

Acknowledgment

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2020R1A2C2004864).

References

Pakkenberg B, Pelvig D, Marner L, Bundgaard M J, Gundersen H J G, Nyengaard J R and Regeur L 2003 Exp. Gerontol. 38 95

Abbott L F and Nelson S B 2000 Nat. Neurosci. 3 1178

Lee, Jaehun, et al. "Proton conduction in a tyrosine‐rich peptide/manganese oxide hybrid nanofilm." Advanced Functional Materials 27.35 (2017): 1702185.

Sung, Taehoon, et al. "Effects of proton conduction on dielectric properties of peptides." RSC advances 8.59 (2018): 34047-34055.

Song, Min-Kyu, et al. "Proton-enabled activation of peptide materials for biological bimodal memory." Nature Communications 11.1 (2020): 1-8.

Figure 1
Interface Lithiophobicity Regulation for Lithium Metal Solid-State Batteries
Authors: He Xinzi , Ji Xiao , Wang Chunsheng
Published: July 2022

Solid-state lithium batteries (SSLBs) using garnet electrolytes potentially have a higher energy density and are safer than commercial liquid organic electrolyte Li-ion batteries. However, SSLBs still face challenges of lithium dendrite growth and high interface resistance. In this work, we addressed both challenges by doping strontium (Sr) into lithium anodes. Different from all previous reported metal/metal oxide coating on garnet or lithium alloy anodes that forms lithiophilic interlayer at Li | garnet, strontium/strontium oxide are enriched on the interface between Li and garnet forming a lithiophilic/lithiophobic bifunctional layer of Li-Sr/SrO-doped-Li2O. This interlayer simultaneously reduces the interfacial resistance and suppresses the growth of lithium dendrite, which is confirmed by comprehensive material characterizations, simulations and electrochemical evaluations using Ta-doped LLZTO (Li6.5La3Zr1.5Ta0.5O12) as a model solid-state electrolyte. The unique stability of the lithiophobic SrO doped Li2O layer against Li prevents reducing the garnet and suppresses lithium dendrite, which distinguishes it from all reported alloy electron-conductor interlayers. The optimized Li-Sr | LLZTO | Li-Sr symmetrical cells have a critical current density of 1.3 mA/cm2 and can be cycled for 1,000 cycles under 0.5 mA/cm2 at room temperature. The bifunctional lithiophilic/lithiophobic interlayer provides a new strategy for high-performance garnet solid-state lithium batteries.

Figure 1
Plasma Charge Carrier Attachment Induced Transport in Solid Ionic Materials
Authors: Weitzel Karl-Michael , Wiemer Jan L. , Schäfer Martin
Published: July 2022

Lithium aluminum germanium phosphate of the stoichiometric formula Li1.5Al0.5Ge1.5(PO4)3 has been studied by means of the femtosecond laser plasma charge attachment induced transport (fs-plasma CAIT) [1]. The technique is based on attaching polarity selected charge carriers from a plasma to the front side of a sample, which induces transport of mobile charge carriers in the bulk of this sample. First, in a conductivity study, an activation energy of 0.73 eV for lithium ion transport has been measured by means of proton attachment. Second, a constant-voltage attachment experiment employing deuterium ions has been performed and subsequently analyzed by time-of-flight secondary ion mass spectrometry. The resulting concentration depth profile revealed a replacement of native lithium ions by deuterons in the first 350 nm of the sample. A theoretical analysis of the profile by means of the Nernst−Planck−Poisson equations provides access to the concentration dependent diffusion coefficient and the unique site energy distribution of the natively contained lithium ions. A full width at half-maximum of 113 meV for the SED of the Li+ ions is determined. The approach discussed can be applied to many more materials, where the potential energy landscape affects the function.

More recent efforts in studying solid state ionic materials by means of the Plasma-CAIT technique will also be presented.

[1] Jan L. Wiemer, Martin Schäfer, and Karl-Michael Weitzel, J. Phys. Chem. C, 125, 4977−4985, (2021)

Figure 1