bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and Characterization of Epitaxially-Fused Quantum Dot Superlattices at the Single Grain Limit
Authors: Abelson Alex , Qian Caroline , Law Matt 
Published: August 2024

Epitaxially-fused superlattices of colloidal quantum dots (QD epi-SLs) may exhibit electronic minibands and high-mobility charge transport, but doing so requires epi-SLs with extremely high degrees of spatial and chemical (compositional) uniformity. In this talk, I will discuss both our efforts to understand and improve the epi-SL formation process, as well as recent charge transport studies on single epi-SL grains.
Epi-SLs are synthesized from a parent SL structure, typically composed of QDs with long insulating ligands. Over the past several years, we have developed insight into the physical and chemical mechanisms by which this parent SL structure is converted into an epi-SL. I will present detailed, multi-model structural characterization of the SL structures, which unveils the astonishing choreographic process by which millions of QDs rotate and translate, in concert, to form the epi-SL.
This structural transformation is initiated by chemical changes to the QD ligand layer, usually through manual introduction of liquids into the SL film. Mechanistic studies into this ligand-exchange process reveal a multi-step chemical sequence that initiates with a simple acid-base reaction. We exploit this insight to fabricate epi-SLs by means of photochemical triggering (using ultraviolet illumination) rather than alternative “hands-on” techniques which suffer from poor experimental control and pronounced chemical inhomogeneity and structural damage in the films. The use of light to trigger the SL conversion process enables much finer control in both the temporal and spatial domains, opening the door to much larger-area SL films and direct photopatterning of epi-SLs.
In the latter portion of the talk, I will present recent work charge transport studies in individual, highly-ordered PbSe QD epi-SL grains. One technical challenge in making these devices is the inherent mismatch in using traditional microfabrication techniques to make single-grained devices of air-sensitive materials. Here, we demonstrate the air-free fabrication of microscale field-effect transistors (μ-FETs) with channels consisting of single PbSe QD epi-SL grains (~ 1 -10 µm grain sizes) and analyze charge transport phenomena in these samples. The devices exhibit p-channel or ambipolar transport with a hole mobility as high as 3.5 cm2 V–1 s–1 at 290 K and 6.5 cm2 V–1 s–1 at 170–220 K, one order of magnitude larger than that of previous QD solids.
Using Three-Dimensional Carbon and Boron Nitride to Improve the Properties of Polyethylene Oxide-Based Solid-State Electrolytes for Li Ion Batteries
Authors: Wong Andrew Barnabas 
Published: August 2024

Polyethylene oxide (PEO)-based solid-state electrolyte (SSE) is attractive due to its excellent adhesion with electrodes and good processability. However, lithium dendrites easily penetrate PEO because of their soft nature, which results in inferior battery performance and safety issues. In this talk, we will discuss the development of 3D (insulating) amorphous carbon and 3D amorphous BN to improve the properties of polyethylene oxide (PEO)-based solid-state electrolytes for Li ion batteries.
For the 3D amorphous carbon, we developed a novel self-healing PEO-based SSE is prepared by incorporating 2 wt% amorphous three-dimensional carbon (3DC). This SSE possesses suitably low electronic conductivity for battery applications (on the order of 10^−9 S/cm), which is five orders of magnitude lower than its ionic conductivity (10−4 S/cm) at 60 °C. In addition, the improved fluidity and strong adhesion between the 3DC and the PEO matrix contribute to the self-healing ability of SSE, which will repair the cracks of SSE formed during battery cycling. Moreover, this SSE shows enhanced ionic and thermal conductivities and mechanical strength, suppressing the formation and growth of lithium dendrites. As a result, this SSE exhibits excellent electrochemical stability, achieving 5000 h of stable cycles in lithium symmetric cell (0.1 mA cm−2, 0.1 mAh cm−2) and 850 long-term stable cycles for the LFP//Li full cell at 1 C (0.31 mA cm−2).
For the 3D amorphous BN, we have developed the first synthesis of powdery hexagonal boron nitride (h-BN). This synthesis introduces a novel NaCl-glucose assisted strategy to synthesize micron-sized 3D h-BN with a honeycomb-like structure. When incorporated into polyethylene oxide-based electrolytes for Li-ion batteries, 5 wt% of 3D h-BN significantly enhances ionic conductivity and mechanical strength. Consequently, this composite electrolyte demonstrates superior electrochemical stability; it delivers 300 h of stable cycles in the lithium symmetric cell at 0.1 mA cm-2 and retains 89 % of discharge capacity (138.9 mAh/g) after 100 cycles at 1 C in the LFP//Li full cell.
These two approaches reveal that 3DC and 3D h-BN can be used to improve the properties of PEO-based electrolytes of Li-ion batteries.
(Keynote) Science and Art of Additives for Electrodeposition of Soft High Magnetic Moment Alloys
Authors: Brankovic Stanko 
Published: August 2024

Current trends demonstrate that electrodeposited soft high magnetic moment (SHMM) alloys will be the material of choice for fabrication of future magnetic nanostructures in magnetic recording, microelectronics, and MEMS technologies. The research in these areas is driven by the need for ultimately soft magnetic alloys with high magnetic moment, high electrical resistivity, good corrosion resistance and low stress levels. A common approach to achieve these properties is use and formulation of different additives. Our understanding of their effects/action is essential and has to be improved and quantified1,2.
In this talk, a review of the current state of the art in understanding of the additive action will be presented. This includes additive incorporation mechanisms3,4 and their relation to observed properties of SHMM alloys (CoFe, CoNiFe, and NiFe). Additive adsorption phenomenon is critically reviewed in correlation to stress in SHMM alloys, grain size, and surface morphology. Results and analytical models describing the effect of additives as a function of their formulation in the plating baths are discussed.
References:
1) E. I. Cooper, C. Bonhote, J. Heidmann, Y. Hsu, P. Kern, J. W. Lam, M. Ramasubramanian, N. Robertson, L. T. Romankiw and H. Xu, IBM J. Res. & Dev., 49, 103 (2005)
2) S. Riemer, J. Gong, M. Sun, I. Tabakovic. J. Electrochem. Soc., 156, D439, (2009).
3) S. R. Brankovic , R. Haislmaier, and N. Vasiljevic, Electrochemical and Solid State Lett. 10(6), D67 (2007).
4) J. George, S.-E. Bae, D. Litvinov, J. Rancheler, and S. R. Brankovic, Journal of the Electrochemical Society, 155 (9) D589 (2008).
(Invited) Electrochemical Marine Carbon Dioxide Removal (mCDR)
Authors: Loretz Jeremy 
Published: August 2024

Ebb Carbon is developing an electrochemical system to safely remove carbon dioxide from the atmosphere and store it in the ocean as dissolved inorganic carbon. The core process uses bipolar electrodialysis (BPED) to process incoming seawater into aqueous acid and alkaline seawater. The acid is kept on land and used for beneficial purposes that result in its neutralization. The alkaline seawater is returned to the ocean, shifting the carbonate buffer system toward carbonate, resulting in the removal of CO2 from the air into oceanic bicarbonate as air-sea equilibration is restored.
For the mCDR system to be impactful on a global level, it must reach gigaton scale while being energy efficient and cost effective.The BPED stack dominates the energy demand of the system and is a prime design task for Ebb Carbon. The stack and system are undergoing development and testing in Ebb Carbon’s labs as well as at the labs of institutional partners. Combining all of these system elements requires a multitude of scientific and engineering disciplines to work together. In this talk, I will discuss the potential for improving the energy and Faradaic efficiencies of these systems, including the opportunity for collaboration with the electrochemical research community.
Reversible Carrier Concentration Control on Ultra-Thin in2O3 By Viologen Molecules Charge Transfer Method
Authors: Wang Sung-Tsun , Chen Jiun-Tai , Lien Der-Hsien 
Published: August 2024

Ultra-thin Oxide semiconductor fabricated by atomic layer deposition (ALD) is one of the promising candidates, due to their ultra-thin thickness and being highly compatible with the silicon process.[1] However, further tuning the oxide semiconductor's carrier concentration is still an interesting issue. Although annealing is a widely used way, the increase in thermal budget is unwilling to be met. To adjust the carrier concentration without increasing the thermal budget, viologen molecule, a strongly n-type dopant which have been successfully applied to different material systems including 2D,[2] CNT,[3] ultra-thin Ⅲ-Ⅴ,[4] has been used in the In2O3 transistor(as shown in Figure 1a). After viologen treatment, the viologen dopants increased the carrier concentration and caused a difference of n
2D, which is 2 × 1012 cm-2 of 2 nm thickness in In2O3, without degrading the mobility under the same overdrive voltage. The In2O3 transistor achieves an electron sheet density of 6.8 × 1012 cm−2. To further expand the function, viologen dopants are modified by hydroxy group. With hydroxy group modifying, the viologen dopants can be removed by acetone and be re-treated back on the In2O3 again. The reversible cycle of viologen treatment can be repeated multiple times without harming the In2O3 device (as shown in Figure 1b). Precise control of the threshold voltage allows for fine-tuning of the transistor between depletion mode and enhancement mode. Based on this, a depletion load inverter has been demonstrated. This result shows that the viologen dopants and In2O3 have the potential to be further integrated with other low dimensional materials in BEOL without raising the thermal budget while tuning the carrier concentrations.

Figure 1. a) Schematic representation of the structure of a In2O3 bottom-gate transistor and the viologen charge transfer process. b) The transfer characteristics of In2O3 transistors repeatedly treated and removed of OHV for four cycles.

References

(1) Si, M.; Lin, Z.; Chen, Z.; Sun, X.; Wang, H.; Ye, P. D. Scaled Indium Oxide Transistors Fabricated Using Atomic Layer Deposition. Nat. Electron.
2022, 5 (3), 164-170. DOI: 10.1038/s41928-022-00718-w.
(2) Kiriya, D.; Tosun, M.; Zhao, P.; Kang, J. S.; Javey, A. Air-Stable Surface Charge Transfer Doping of MoS2 by Benzyl Viologen. J. Am. Chem. Soc.
2014, 136 (22), 7853-7856. DOI: 10.1021/ja5033327.
(3)Kim, S. M.; Jang, J. H.; Kim, K. K.; Park, H. K.; Bae, J. J.; Yu, W. J.; Lee, I. H.; Kim, G.; Loc, D. D.; Kim, U. J.; Lee, E.-H.; Shin, H.-J.; Choi, J.-Y.; Lee, Y. H. Reduction-Controlled Viologen in Bisolvent as an Environmentally Stable n-Type Dopant for Carbon Nanotubes. J. Am. Chem. Soc.
2009, 131 (1), 327-331. DOI: 10.1021/ja807480g.
(4) Takei, K.; Kapadia, R.; Li, Y.; Plis, E.; Krishna, S.; Javey, A. Surface Charge Transfer Doping of III–V Nanostructures. J. Phys. Chem. C
2013, 117 (34), 17845-17849.

Figure 1
Selective Isotropic Dry Etching of SiO2 Using F/H-Based Pulsed Remote Plasma and a Vapor Phase Solvent
Authors: Lee Ji Yeon , Kim Dae Whan , Gil Hong Seong , Kim Doo San , Jang Yun Jong , Kim Dong Woo , Lee Jiyeon 
Published: August 2024

Isotropic etching generally employs liquid-based wet etching techniques. However, due to the high integration of devices, conformal etching is challenging in patterns with a high aspect ratio because liquid chemicals struggle to penetrate inside the pattern. Additionally, during the drying process after chemical treatment, pattern collapse is observed due to surface tension. Therefore, there is a need for dry isotropic etching techniques to replace wet etching techniques in next-generation device manufacturing processes.
Typically, when high selectivity SiO2 isotropic dry etching is required, F-base/H-based gas mixtures are utilized to form HF, which serves as an etchant for SiO2. SiO2 can be dry etched through two different mechanisms. First, HF reacts directly with H2O or alcohol, etching SiO2. The other way is to produce (NH4)2SiF6 salt from the reaction of NH3, which can be formed in a plasma containing NH3 and NF3. This (NH4)2SiF6 salt is sublimated and removed by a following heating process at a temperature over 100ºC.
The process above has some disadvantages, such as lowering the etch selectivity of SiO2 over Si and Si3N4 because Si and Si3N4 can be etched by F radicals remaining in the plasma. This study aimed to overcome these disadvantages by controlling the F radical through pulsing the remote plasma during the discharging of F-based/H-based gas mixtures for the formation of HF. By pulsing the remote plasma, SiO2 could be selectively etched at a higher etch rate relative to those of Si and Si3N4. Additionally, various types of H/F-based gas mixtures that do not contain nitrogen while producing HF were investigated to prevent the formation of ammonium powders, which can be a source of contamination in the chamber. Futhermore, the etching mechanisms were identified through gas phase anlysis and surface analysis. Also, any possible surface damage during the etching process was investigated.
Investigating Ion-Coupled Electron Transfer of Conducting Polymers
Authors: Altuğ Fatma , Ülgüt Burak 
Published: August 2024

After years of basic and applied studies of electron transfer in redox active films, the fundamentals of ion transfer during the exchange remain to be understood. Empirically, the processes are ion-transport limited. Using a conducting polymer as a model system, we aim to study the relationship between electron and ion transfer during redox switching.
We work on electrochromic conducting polymers because of their observable and detectable color changes in addition to the current during the redox switching. Tracing optical signals can enhance the understanding of electrical signals from redox reactions. When a potential is applied to the electroactive polymer, its color will change from lighter to darker or vice versa. Keeping in mind that absorbances are additive, the ratio of the contents that make up the overall color of the polymer changes. This ratio change is directly proportional to the amount of matter under inter-conversion during the redox reaction.
This study aims to explore the ion-electron mechanism in conductive polymers using the simultaneous Spectro-CV method. To achieve this, we conducted cyclic voltammetry at exceptionally high scanning rates, leveraging the conductive polymer's color-changing property. At these high rates, ion movement was restricted due to limited time for forward and backward motion, potentially reaching a point of stagnation. The investigation focused on whether the polymer would continue changing color, providing insights into ion-electron transfer. In addition, we are conducting EIS measurements alongside simultaneous Spectro-CV measurements and attempting to fit the impedance response of the polymer with an appropriate model. We aim to track the time constants provided by the polymer at different voltage values and understand the corresponding physical processes associated with these time constants. Additionally, we aim to use our EIS model to validate the desired redox current information obtained from optical data. We mathematically reach the faradaic portion of the total current with EIS and compare the results obtained from optical data.

References

[1] Nicholson, R. S., Shain, I. (1964). Theory of stationary electrode polarography. single scan and cyclic methods applied to reversible, irreversible, and kinetic systems. Analytical Chemistry, 36(4), 706–723.
2 Laviron, E. (1979). General expression of the linear potential sweep voltammogram in the case of diffusionless Electrochemical Systems. Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 101(1), 19–28.
3 Lyons, M. E. G. (1994). Electroactive Polymer Electrochemistry

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(Invited) Ga2O3 Semiconductor Devices for High-Temperature Operation
Authors: Zakutayev Andriy 
Published: August 2024

Beta phase of gallium oxide (Ga2O3) has attracted a lot of attention as an ultra-wide band gap semiconductor for applications in high-power electronic devices. High power operation often comes with increased temperatures of the devices due to joule heating, especially in semiconductors like Ga2O3with low thermal conductivity. However, electrical performance and reliability of the Ga2O3based diodes and transistors at very high temperature, above 400C, is not well established.
In this talk, I will present our recent experimental results on fabrication of Ga2O3semiconductor devices for applications as high-temperature diodes and hydrogen gas sensors. The fabricated Ga2O3/NiO p-n heterojunctions allow for device operation with >100-1000 rectification ratio up to 400-600C [1]. Despite the stable ultrathin Ohmic contact [2], the device performance degrades over tens of temperature cycles and hundreds of hours at these elevated temperatures, likely due to instability of the rectifying contact. We propose and implement alternative interfacial rectifying contact layers, that enable both high performance and long reliability of these high temperature Ga2O3 semiconductor devices.
[1] Sohel, Zakutayev et al Physica Status Solidi (a) 220 2300535 (2023)
[2] Callahan, Zakutayev et al J. Vac. Sci. Technol. A 41, 043211 (2023)
(Invited) Scalable Manufacturing and Application of Piezoelectric Biomaterials
Authors: Wang Xudong 
Published: August 2024

Piezoelectric materials are a group of important functional building blocks that interfacing the human body by coupling biomechanical energy and electricity. So far, many technology innovations have advanced piezoelectric materials and composites toward a broad range of biomedical applications, which possess unique biocompatibility and flexibility. Fundamentally, materials design and engineering draw the boundary where this technology may advance. In this talk, I introduce our most recent development of piezoelectric materials and composites that are particularly designed for implantable nanogenerator applications. First, I present our wafer-scale approach to creating piezoelectric biomaterial thin films based on amino acids. The self-assembled sandwich film and truss-like structures enabled both strong piezoelectricity and largely improved flexibility. Then, new ferroelectric composites are presented as a new material used in 3D printing for directly manufacturing of piezoelectric architectures with tunable piezoelectric and mechanical properties. Toward the end, novel applications of implantable piezoelectric materials are introduced, which enable the closed-loop electrostimulations for many biomedical therapeutics.
References:
J Li, C Carlos, H Zhou, J Sui, Y Wang, Z Silva-Pedraza, F Yang, Y Dong, Ziyi Zhang, T.A. Hacker, B. Liu, Y. Mao, X. Wang, Nature Communications 14, 6562 (2023).
J. Li, Y. Long, Z. Zhang, L. Wang, J. Sui, Y. Dong, Y. Wang, R. Taylor, D. Ni, W. Cai, P. Wang, T. Hacker, X. Wang, Science, 373, 337–342 (2021).
Simulation of a Passive Osmosis-Integrated Electrolyzer for Seawater Electrolysis
Authors: Ghasemi Masoomeh , Al Murisi Mohammed , Mustain William Earl , Shimpalee Sirivatch 
Published: August 2024

The requirement for extremely pure water in electrolysis, combined with the abundant presence of seawater, has prompted extensive research into the creation of direct seawater electrolysis technology for decades [1]. However, these efforts have had limited success due to other limiting issues that arise, including competition with the chloring evolution reaction, increased membrane resistance, corrosion of electrode materials and electrode scaling due to the presence of multivalent cations. To avoid these issues, seawater is typically first desalinated using reverse osmosis, but that comes with additional energy cost. Therefore, our project has proposed a new reactor that integrates passive osmosis (extracting fresh water from seawater) with electrolysis.
In this presentation, we will discuss the operation of the osmosis-integrated electrolyzer and show theoretical predictions of the osmotic pressure differential and water flux/velocity profiles under different conditions. The numerical model that will be presented was applied to three different cell designs that have been physically developed. The first cell consists of two anion exchange membranes (AEMs) with two side chambers containing KOH and a middle chamber containing Sodium Chloride (NaCl). The second cell has KOH in one outer compartment and H2SO4 in the other. The central compartment containing NaCl is separated from KOH compartment by an AEM and the H2SO4 compartment by a cation exchange membrane (CEM). The third cell eliminates the central compartment and allows the osmosis to occur outside of the cell.
The simulation results show that by increasing the concentration of KOH and H2SO4 in the side chambers for all three models, the amount of water transferred from the middle chamber, containing of NaCl to the side chambers increases. The simulation results were validated by experiments (Figure 1). In addition, the model is able to quantify the transport of ions in the system, including chloride ions through the AEM. Lastly, the mass transfer model is integrated with an electrochemical model where an anode and cathode are added to the system to consume the water that is transported through the membranes.
Reference:
[1] M. A. Khan, T. Al-Attas, S. Roy, M. M. Rahman, N. Ghaffour, V. Thangadurai, S. Larter, J. Hu, P. M. Ajayan, and M. G. Kibria, “Seawater electrolysis for hydrogen production: a solution looking for a problem?” Energy & Environmental Science, 14, 4831 (2021).

Figure 1
(Invited) Overview of Ion-Conducting Polymer Membranes and Membrane Separators for Water Electrolysis
Authors: Bae Chulsung 
Published: August 2024

Traditional liquid alkaline electrolyzer uses a porous diaphragm to allow diffusion of hydroxide ion from a feed of concentrated KOH solution while separating anode and cathode and suppressing mixing of produced H2 and O2 gases. Although liquid alkaline electrolyzer is considered as a matured technology, recent renaissance of new electrode separators suggests there is significant potential for improvement in efficiency and cost reduction by lowering area specific resistance and increasing operation current density.
Ion-conducting polymers (e.g., proton or hydroxide) are used as a key component of polymer electrolyte membranes, such as acidic proton exchange membrane (PEM) and alkaline anion exchange membrane (AEM), in electrochemical energy conversion and storage technologies including water electrolyzers. For example, the state-of-the-art PEM electrolyzers have used Nafion for a PEM and ionomer catalyst binder for decades, though it is not ideal proton-conducting membrane material for those applications. Recent pressure on perfluoroalkyl substrates (PFASs) from government and environmental activist groups due to their environmental and health hazard has attracted the development of alternative polymer electrolyte membranes based on hydrocarbon polymers within electrochemical society. Compared to perfluorosulfonated Nafion, hydrocarbon ion-conducting polymers (both PEMs and AEMs) can offer advantages of flexible synthetic tunability, lower gas permeability, and importantly lower production cost.
In this tutorial, an overview of recent progress in the development of advanced porous membrane separators, PEMs and AEMs, their key membrane properties, and the state-of-the-art performance in applications of water electrolyzers will be discussed.

Figure 1