bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient CO and Acrolein Coproduction via Paired Electrolysis
Authors: Wang Xue , Li Peihao , Li Peihao
Published: December 2024

Interest has grown recently in paired electrolysis: the combining of a productive cathodic reaction, such as CO2electroreduction (CO2RR), with selective oxidation on the anode. Unfortunately, direct electro-oxidation reactions typically exhibit limited Faradaic efficiencies (FEs) towards a single product. Here we pursued paired electrolysis and focused on acidic CO2RR and the model organic oxidation reaction of allyl alcohol oxidation reaction (AOR) to acrolein. We report a system having (96 ± 1)% FE of CO2 to CO on the cathode; and (85 ± 1)% FE of allyl alcohol to acrolein on the anode. We thereby lower, as a result of this pairing with organic oxidation on the anode, the full-cell voltage of the system by 0.7 V compared to the best previously-reported full-cell acidic CO2-to-CO studies at the same 100 mA cm-2 current density. The acidic cathode avoids carbonate formation, enabling us to document a single-pass utilization of CO2 of 84% on the cathode, fully a 6× improvement in the atom-efficiency of CO2 utilization relative to the best prior CO2-to-CO reports undertaken above 100 mA cm-2. Energy consumption analysis suggests that, when producing the same amount of CO, this CO2RR-AOR system reduces energy consumption by an estimated 1.6× compared to the most energy-efficient prior acidic CO2-to-CO ambient-temperature electrolysis systems.

Figure 1
Optimization of Operating Conditions to Improve the Performance of Brine Electrolyzer for Minerialization of Waste Cement and Steel Slag
Authors: Jung Kwang-Deog , Kim Jaewon , Rizvi Syed B.H. , Lee Ki Bong , Ha Heung Yong
Published: December 2024

The most important unit in mineralization to produce nano-CaCO3 from waste inorganic materials is the electrolyzer producing both HCl and NaOH at the applied potential less than 1.5 V, because both the extraction efficiency of Ca ions from waste concrete and steel slag using 0.5M HCl and the carbonation efficiency to produce CaCO3 are almost about 100% in the mineralization process [1,2]. The nano-CaCO3 can be produced through CO2 bubbling into Ca(OH)2 slurry, which is prepared from the purified fitrate solution using 1 M NaOH produced from the electrolyzer. The impurities such as Fe, Al and Mg are removed in the purification step. One of the drawbacks of the electrolysis of NaCl is that it is very difficult to improve reaction rate, because the applied potential for the electrolyzer should be less than 1.5V to achieve the objective of CO2 mitigation. Another one is to maximize the caustic efficiency. Unfortunately, both the applied potential and caustic efficiency have a trade-off relationship. This study aims to develop a way to improve the performance of electrolyzers by optimizing operating conditions. It has been found that the applied voltage and operating temperature among others can effectively enhance the reaction rate and caustic efficiency simultaneouly. Under the optimal conditions, the reaction rate is significantly enhanced more than 2 times and the caustic efficiency more than 1.5 times compared to those obtained under standard conditions. This is because the relative permeation rate of Na+ over H+ through a Nafion membrane is elevated by increasing temperature and applied voltage. Analytical work has been conducted to reveal the mechanism of performance improvement by investigating the permeation behaviors of the ions through the Nafion membrane. It is found that the permeation rate of an ion through membrane is interfered by the presence other ions. That is, the permeation of sodium ions is significantly hindered by protons, but this interference is dramatically overcome by raising temperature and applied voltage. A long-term test more than 1500 hours is also carried out to test the stability and feasibility of the electrolyzer. In this study, we have proven that the performance of brine electrolyzer could be successfully improved by optimizing the operating conditions such as temperature and applied voltage.

References

Lee J., Ryu K.H., Ha H.Y., Jung K.D., and Lee J.H., J. CO2 Utilization, 37 (2020) 113.

Park K.H., Lee K.R., Jo H., Park J.W. Lee J.H., Jung K.D., CO2 Utilization, in revision.
Effect of Polarity Reversal on Mitigating Passivation Layer during Iron Electrocoagulation
Authors: Jang Gyoung Gug , Dutta Swapnamoy , Su Yi-Feng , Jun Jiheon , Keum Jong , Kim Kyungho , Chellam Shankararaman , Tsouris Costas
Published: December 2024

Iron based electrocoagulation (Fe-EC) is a promising contaminant removal technology based on electrochemical dissolution of iron from steel electrodes; however, the Fe-EC performance declines over extended operation associated with fouling layer formation. In this study, we characterized the fouling layer growth in a continuous-flow EC reactor for silica and hardness removal from secondary effluent of wastewater. The fouling layer exhibited a passivating effect, requiring a higher anode potential to maintain the desired electrical current, thus significantly decreasing Faradaic and pollutant removal efficiencies. To better understand the evolution and composition of the passivation layer, we conducted time-resolved microscopy, X-ray spectroscopy, and electrochemical analysis to obtain critical insights into the structure, morphology, and elemental composition of the fouling layer at different stages of formation. Experimental observations indicated that an initial thin, porous iron oxide layer formed on the anode surface. During extended operation, this oxide layer thickened to a dense, over 100-µm black iron oxide layer containing magnetite due to limited oxygen availability near the surface where iron ions were released. To address the challenge posed by the fouling layer, polarity reversal was applied to break up the fouling layer and restore anode reactivity, resulting in recovering Faradaic and pollutant removal efficiencies. The mechanism responsible for this improvement could be associated with the evolution of gas at the cathode surface after electrode reversal, which effectively removed the fouling layer. This work not only provides a deeper understanding of fouling-layer formation in Fe-EC, but also presents a practical approach to maintain the reactivity of the electrodes and optimize the effectiveness of Fe-EC systems.
Analyzing Bismuth Catalysts for Nitrogen and Nitrogen Oxides Reduction: A DFT Study Comparing Activation Mechanisms and Examining Dopant Effects
Authors: Lee Dong-Kyu , Jeong Yujin , An Tae-Yong , Kim Tae-Hoon , Kim Mincheol , Kim Jung Kyu , Sim Uk
Published: December 2024

Considerable research has been dedicated to synthetic ammonia production for hydrogen energy carriers as well as fertilizer constituents. However, the intensive energy demanding of the Haber-Bosch process have raised concerns. Electrochemical ammonia synthesis emerges as a promising alternative, with the efficacy of the electrochemical catalyst being paramount. Bismuth, renowned for its ability to forge robust bonds with nitrogen owing to its p-electrons, has exhibited potential as a catalyst for this process. These characteristics enable not only the adsorption of nitrogen but also the effective adsorption of nitrate. In this investigation, we confirmed electrochemical performance of nitrogen and nitrate reduction (NRR and NO3RR) and utilized density functional theory (DFT) calculations to explore the mechanisms underlying the conversion of nitrogen and nitrogen oxides to ammonia on bismuth catalysts. In the NO3RR, we obtained a yield of 533.28 μg h-1 mgcat
-1 and an FE of 20%, while in the NRR, we achieved a yield of 19.424 μg h-1 mgcat
-1 and an FE of 3.20%. Our objective is to assess the impact of doping various elements into the catalysts during the reduction reaction and propose a coordination strategy to bolster ammonia production. Based on the computational results, metals like Mn, In, W, Zn, Cu, Co, along with several other elements, were identified as candidates. By comparing our theoretical projections with experimental outcomes, we evince the selectivity of bismuth and emphasize its potential for electrochemical ammonia synthesis.
Modeling Framework for the Assessment of a Sustainable Hydrogen Production and Supply Chain Network in California
Authors: Zaki Mohammed Tamim , Jeong Seongeun , Weber Adam Z. , Breunig Hanna
Published: December 2024

The cost-effective and sustainable deployment of hydrogen supply and demand networks, especially in large economic regions like California, can be challenging considering the spatial-temporal availability and variability of the different actors across the network such as production processes, distribution modes, and end-users. In this presentation, we will provide an overview and demonstration of a modeling framework used to assess the environmental, economic, and human health impacts of plausible hydrogen production and supply chain networks in California. Scenarios focus on green hydrogen production pathways using water electrolysis and biomass gasification. End-use applications included in the model are transit, medium and heavy-duty trucking, port authorities, and power and aviation companies that currently consume natural gas, diesel, and aviation fuel for their day-to-day operation. Representative locations for hydrogen production and end-use are based on recent projections of the hydrogen economy in California.

All mass and energy flows, as well as estimated emissions, are based on H2A process model designs and projections of technology performance, literature review, and LBNL process, economic and life cycle modeling, and not on company data for the sake of this presentation. Human health impacts are included following methodologies developed for the University of California Irvine HyDeal project. Life cycle phases associated with hydrogen production include feedstock preparation (water and biomass), energy production and consumption (renewable, grid, and combination of renewable and grid electricity), maintenance (chemical utilization in electrolysis and natural gas combustion in gasification), carbon sequestration, hydrogen storage (compression and liquefaction), and distribution (truck and pipeline). We apply the framework utilizing California specific emission factors, financial data, and human health damages and explore the impact of network characteristics on results. Example variations include: the inclusion of policy incentives or not, different representations of the electricity grid and source, electrolysis versus gasification versus combinations of both for production, liquefaction versus compression based on producer capacity cutoffs, transportation truck versus pipeline based on existing infrastructure, and ultimate end use. Comparison of these different scenarios can help inform future projects by demonstrating the trade-offs among environmental, economic, and human health impacts. This model, automated in R, is a starting platform upon which new analysis, modeling capabilities, locations, and emission factors can be rapidly tested and integrated.
Atomic Layer Deposition of Noble Metal Single Atoms and Nanoparticles for Electrocatalytic Applications
Authors: Macak Jan M. , Bawab Bilal , Rodriguez Pereira Jhonatan , Zazpe Raul
Published: December 2024

Platinum group metals such as Pt, Ru, Pd, Ir, etc., have superior performance for various catalytic applications [1]. Due to their scarcity, efforts were being made to reduce the mass/loading or replace these noble metals. Atomic Layer Deposition (ALD) is one among the best technique to facilitate lowering of loading mass on a support of interest [2,3]. Due to the governing surface energy variations between noble metals and support surfaces, the growth initiates as nanoparticles (NP) and with a further increase in ALD cycles the agglomeration among NP’s dominates over the individual NP size increase, thus developing thin films of relatively higher thickness.

For electrocatalytic applications, it is important to choose the right substrates. Among available substrates, carbon papers and titania nanotube layers are best choices considering their physio-chemical properties, availability and low costs incurred.

The uniform decoration of these substrates by NPs of catalysts proved to be highly efficient in electrocatalysis, as shown in our recent papers [3-6].

The presentation will introduce and describe the synthesis of different noble metal NPs by ALD on important substrates. It will also include the corresponding physical and electrochemical characterization and encouraging results obtained in electrocatalysis.

References:

[1] Huang, Z. F. et al. Advanced Energy Materials vol. 7 (2017) 1700544.

[2] Yoo, J. E. et al. Electrochem. commun. 86 (2018) 6

[3] Anitha, V. C. et al. J. Catal. 365 (2018) 86.

[4] Sitaramanjaneya M. Thalluri & Macak, J. M. Small 19 (2023) 2300974.

[5] Bawab, B. & Macak, J. M., et al., Electrochim. Acta 429 (2022) 141044

[6] Bawab, B. & Macak, J. M., et al., Chem. Eng. Journal 482 (2024) 148959
(Invited) Development of High-Bandwidth GaN-Based Micro-LEDs for Visible Light Communication
Authors: Tian Pengfei , Zhang Zhen , Jin Zuxin , Lin Runze
Published: December 2024

With the expectation of extremely high-capacity requirement of 6G networks, visible light communication (VLC) has abundant frequency resource and excellent performance in 6G integrated communication in space, air, underwater, indoor, and car networks [1]. The micro light emitting diode (micro-LED) is regarded as a reliable light source for high-speed VLC and is capable of illumination while providing communication. Compared to the traditional light source, micro-LED possesses better characteristics such as high bandwidth, low power consumption, long lifetime and high reliability [2-3].

In this work, we made improvements in the micro-LED fabrication compared with the common negative doped GaN (common-n) devices we produced by shallow etching before [4]. Micro-LEDs can be manufactured into completely separate pixels for independent control by deep etching. For green micro-LEDs with a wavelength of 510nm, the light output power of deep etching one increased. At the same working current density, the -3dB bandwidth of deep etching micro-LED has an average growth of 50% compared to shallow etching one. Benefit from the promotion of optical power and -3dB bandwidth, micro-LED with independent etching structure have a better performance in VLC system. A record date rate of 6.58Gpbs was achieved by single green micro-LED employing the orthogonal frequency division multiplexing (OFDM) modulation scheme, which proposes a feasible optimization direction for the integration of micro-LED high-speed VLC and lighting.

REFERENCES:

[1] Chi N, Zhou Y, Wei Y, et al. Visible light communication in 6G: Advances, challenges, and prospects[J]. IEEE Vehicular Technology Magazine, 2020, 15(4): 93-102.

[2] James Singh K, Huang Y M, Ahmed T, et al. Micro-LED as a promising candidate for high-speed visible light communication[J]. Applied Sciences, 2020, 10(20): 7384.

[3] Lin R, Jin Z, Qiu P, et al. High bandwidth series-biased green micro-LED array toward 6 Gbps visible light communication[J]. Optics Letters, 2022, 47(13): 3343-3346.

[4] Zhu S, Qiu P, Shan X, et al. Micro-LED based double-sided emission display and cross-medium communication[J]. IEEE Photonics Journal, 2022, 14(3): 1-5.

Figure 1
Effect of Polymer Type Additives in Selective Wet Etching of Si1-XGex- to Si-Film to Enhance Etch Rate Selectivity
Authors: Lee Changjin , Lee Ji-Eun , Jang Eun-Woo , Kim Ji-Hoon , Park Jinsub , Park Jea-Gun
Published: December 2024

To extend the scalability of the logic transistor beyond the 3-nm process, the architecture of the metal-oxide-semiconductor field-effect transistor (MOSFET) has changed from FinFET to gate-all-around FET (GAAFET). In addition, to continue the scaling of MOSFET further, various concepts of nanosheet architecture devices, including GAAFET, Forksheet FET, and Complementary FET, have been vigorously researched. To fabricate nanosheet devices, releasing Si channels via selective etching of Si1-xGex- to Si-layer is a key process. However, during the selective etching of Si1-xGex- to Si-layer, simultaneous etching of Si- with Si1-xGex-layer is inevitable. Therefore, protecting the Si-layer while selective etching of the Si1-xGex-layer is a major challenge to acquire uniform channel layers (i.e., Si-layers).

In this study, to protect the Si-layer during the selective wet etching of Si1-xGex- to Si-film, we came up with an idea based on the concept of selective chemisorption of polymers on Si- rather on Si1-xGex-film. Functional groups of polymers can chemisorb onto the Si surface, followed by building the hindrance layer that prohibits the etching of Si-film. Thus, we tested the effect of polymer type additives in selective wet etching of Si1-xGex- to Si-film depending on the functional groups (carboxylic group, amine group, alcohol group, etc.) and the molecular weight. To characterize the etching amount of the Si-film during the selective wet etching of Si1-xGex- to Si-film, the wet etching of epitaxially grown 3-periods of Si1-xGex/Si multilayer on Si substrate was performed followed by high-resolution transmission electron microscopy (HR-TEM) analysis. When using a specific type of polymer additive during wet etching, the etching amount of Si-film was >0.5 nm within 2 minutes, while that using without any additive was ~0.8 nm within 2 minutes, indicating that polymer type additive can produce the hindrance layer successfully onto Si-film preventing the etching of Si-film. The HR-TEM images depending on polymer types and mechanism of protecting Si-film during the selective wet etching of Si1-xGex- to Si-film will be presented in detail.

Acknowledgement

This work was supported by the Technology Innovation Program (20022475, Development of wet Etchant capable of high selection etching in microprocesses below 10 nm) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea)

References

[1] Lee, Seung-Jae, et al. "Extremely high selective Si1−xGex-film wet etchant generating highly dissolved oxygen via peracetic acid oxidant for lateral gate-all-around FETs with a logic node of less than 3-nm." Chemical Engineering Journal 475 (2023): 146257.
(Invited) Graded Index Silicon Germanium Photonics Circuits in the Mid-Infrared
Authors: Turpaud Victor , Nguyen Thi Hao Nhi , Bricout Annabelle , Dely Hamza , Frigerio Jacopo , Calcaterra Stefano , Hartmann Jean-Michel , Coudevylle Jean-René , Villebasse Cedric , Bouville David , Alonso-Ramos Carlos , Vivien Laurent , Isella Giovanni , Marris-Morini Delphine
Published: December 2024

Mid-infrared (mid-IR) spectroscopy can be used to identify chemical and biological substances. Indeed, most molecules absorb light at specific wavelengths in the mid-infrared (mid-IR). Mid-IR photonic circuits on silicon chips have recently gained a lot of attention. Indeed, they can provide high-performance with a low power consumption, while being cheap, compact, and light. Germanium (Ge) and silicon-germanium (SiGe) alloys with a high Ge concentration are particularly interesting because of the wide transparency window of Ge extending up to 15 µm. It has been demonstrated for a few years now that a Ge-rich graded SiGe platform relying on a graded SiGe layer epitaxially grown on a Si substrate can be used as a photonics platform for mid-IR operation in a wide spectral range.

In this invited talk, recent developments concerning graded SiGe photonic integrated circuits will be presented. First, passive devices will be reviewed. It will be shown that graded-SiGe waveguides can be used in an unprecedented spectral range, e.g. up to 11 µm. Mach Zehnder interferometers, resonators and integrated Fourier transform spectrometers will be discussed. Then, a large bandwidth light source based on non-linear optical effects in SiGe waveguides [1] will be presented, together with results on integrated mid-IR optoelectronic modulators [2, 3]. Tunable electro-optical frequency-comb generation around 8 µm wavelength based on such integrated modulators will also be discussed [4]. Finally, the recent scale-up of this platform will be shown, with the first demonstration of low-loss mid-infrared waveguides fabricated on a Ge-rich SiGe strain-relaxed buffer grown on an industrial-scale 200 mm wafer [5].

Acknowledgment:

This work was co-funded by ANR Light-up Project (ANR-19-CE24-0002-01) and by European Union (ERC, Electrophot,101097569). This work was partly supported by the French RENATECH network.

References:

[1] M. Montesinos-Ballester, et al, ACS Photonics, 7, 3423-3429, (2020).

[2] T.H.N. Nguyen, et al, Optics Express, 30, (26), 47093 (2022).

[3] T.H.N. Nguyen, et al, Advanced Photonics Research, 2200237 (2022).

[4] V. Turpaud, et al, Laser & Photonics Reviews, 2300961 (2024).

[5] V. Turpaud, et al, to be published, 2024.
Foundational Machine Learning Interatomic Potential to Study Li-Ion Battery Cathode Phase Transformation with Charge Transfer
Authors: Deng Bowen , Zhong Peichen , Jun KyuJung , Riebesell Janosh , Han Kevin , Bartel Christopher J. , Ceder Gerbrand
Published: December 2024

Large-scale simulations with complex electron interactions remain one of the greatest challenges for atomistic modeling of electrochemical systems. Our recent work, Crystal Hamiltonian Graph Neural Network (CHGNet), presents foundational graph-neural-network-based machine-learning interatomic potential (MLIP). The inclusion of charge information by magnetic moment prediction enables CHGNet to better describe both atomic and electronic degrees of freedom, which opens the possibility for a better understanding of electron-redox coupled behaviors that are essential for applications such as battery cathode materials for energy storage.

We demonstrate the use of CHGNet MLIP in electrochemistry by modeling in detail the process by which orthorhombic LixMnO2 transforms to a spinel-like structure. This transformation is facilitated by the valence-dependent Mn migration and charge disproportionation which can only be modeled accurately with an MLIP that captures the very different chemical behavior of transition metals’ different valence states. Moreover, we show the Mn-rich disordered rocksalts (DRX) exhibit similar phase transformation to a spinel-like phase, leading to improved capacity and Li-ion transport kinetics. Our study demonstrates critical atomic-level insights into Li-ion cathode electrochemistry, which became possible with charge-informed long-time simulations at scale enabled by modern AI methods.
Development of a Highly Selective Etching Process for SiO2 over Si and SiNx Using F/H-Based Remote Plasmas and a Vapor Phase Solvent
Authors: Lee Ji Yeon , Gil Hong Seong , Park Woo Chang , Jang Yun Jong , Kim Dong Woo , Yeom Geun Young
Published: December 2024

Isotropic etching is traditionally performed using liquid-based wet etching techniques. However, with the increasing integration of devices, achieving conformal etching in high aspect ratio patterns becomes difficult, as liquid chemicals are limited in their ability to penetrate deep into these structures. Moreover, during the drying phase following chemical treatment, surface tension can lead to pattern collapse. Consequently, there is a growing need for dry isotropic etching methods to replace conventional wet etching in advanced device manufacturing.

In cases where high selectivity for SiO2 isotropic dry etching is required, mixtures of fluorine-based and hydrogen-based gases are typically used to generate HF, which acts as the etchant for SiO2. SiO2 can be etched through two main mechanisms. The first mechanism involves the direct reaction of HF with H2O or alcohol to etch SiO2. The second mechanism involves the formation of (NH4)2SiF6 salt through the reaction of HF with NH3, which occurs in a plasma containing NH3 and NF3. This (NH4)2SiF6 salt is then sublimated and removed in a subsequent heating process at temperatures above 100°C.

The reaction of HF with NH3 to form (NH4)2SiF6 can lead to the generation of ammonium salts that may act as contaminants within the etching chamber. Additionally, this approach necessitates an extra thermal treatment step to eliminate the (NH4)2SiF6 salt. HF can be supplied either directly as vapor or generated through plasma containing fluorine and hydrogen. Plasma-based methods generally offer advantages in terms of safety and process efficiency compared to direct HF vapor usage

In this study, we investigated an isotropic dry etching process in which HF etchant is generated by discharging fluorine-based and hydrogen-based gas mixtures. A vapor-phase solvent is supplied outside the discharge region to ionize HF and directly etch SiO2. When using H2O vapor as the solvent, we achieved the etch selectivity of SiO2 over SiNx and poly Si higher than 100 and 600, respectively, was obtained while having SiO2 EPC of ~30 nm/min by optimized conditions. The etching mechanism was clarified through gas-phase and surface analyses using optical emission spectroscopy (OES), quadrupole mass spectrometry (QMS), and X-ray photoelectron spectroscopy (XPS). To assess pattern collapse, we compared the wet phase and vapor phase processes applied to the Si trench pattern. The results suggest that using fluorine and hydrogen-based remote plasmas with a vapor-phase solvent is promising for highly selective isotropic SiO2 etching in the fabrication of next-generation 3D devices.
Investigation of the Impact of Different Electrode Inhomogeneities on the Voltage Response of Li-Ion Batteries
Authors: Dubarry Matthieu , Beck David
Published: December 2024

Battery degradation is a fundamental concern in battery research, with the biggest challenge being to maintain performance and safety upon usage. From the microstructure of the materials to the design of the electrodes and their assembly in cells, it is impossible to achieve perfect reproducibility. This is problematic because small manufacturing or local variations could have big repercussions on performance and reliability.

In this purely theoretical study, we investigated the potential impact of different inhomogeneities on the performance on two typical Li-ion batteries with a graphite negative electrode and either nickel manganese cobalt oxide 111 or lithium iron phosphate as the positive electrode. Our modeling results showed that out of the nine considered inhomogeneities, only three could affect performance, when at a mild level and randomly distributed, with two unlikely to happen in real cells because they would probably disappear during rest. The only one found to be impactful was inhomogeneities of resistance on the negative electrode. In that case, we predicted an impact on the voltage response that is close to the signature that was attributed to inhomogeneities in the literature. Moreover, such inhomogeneities also open the possibility of a snowball effect as it was shown to induce lithiation inhomogeneities at end of charge when the PE is limiting while the NE in the middle of a well define voltage plateau.

Our study showed that it is necessary to assess the level at which the paralleling is occurring, electrode or full cell, as the model predicts an impact on how much current is flowing within or in-between the electrodes.

While we are well aware of the limitations of this work, we believe it provides a good starting point for discussion with the community.
Data-Driven Prognosis of Lithium-Ion Batteries Thermal Runaway: A Novel Machine Learning Approach
Authors: Liu Lin
Published: December 2024

The widespread use of lithium-ion batteries in electric vehicles and energy storage systems demands accurate methods for predicting and diagnosing their performance, enhancing their safety and reliability. A significant challenge to their broader application is thermal runaway, a key factor compromising the safe use of these batteries. Addressing this issue, our study introduces innovative strategies for the precise prediction and prevention of lithium-ion battery failures. We employ a data-driven prognosis (DDP) approach to analyze battery failures attributed to thermal runaway. This technique effectively identifies anomalies in battery operation and detects faults in battery performance dynamics. Furthermore, we developed an electrochemical-thermal model that accurately represents the internal chemical reactions and thermal behaviors at the cellular level. This model is incorporated with the DDP algorithm to generate critical data-driven model inputs, enabling precise failure predictions. Our findings demonstrate the data-driven algorithm's effectiveness in identifying battery failures caused by thermal runaway, thereby enhancing the safety and operational reliability of electric vehicles and energy storage systems through timely alerts.
High-Mobility Indium Oxide Thin Film Transistors with High Reliability
Authors: Ghediya Prashant , Magari Yusaku , Sadahira Hikaru , Endo Takashi , Furuta Mamoru , Zhang Yuqiao , Matsuo Yasutaka , Ohta Hiromichi
Published: December 2024

Transparent oxide semiconductors (TOSs) based thin-film transistors (TFTs) that exhibit higher field effect mobility (μ
FE) are highly required toward the realization of next-generation displays. Among numerous types of TOS-TFTs, In2O3-based TFTs are the front-running candidate because they exhibit the highest μ
FE ~100 cm2 V−1 s−1. However, the device operation of In2O3 TFTs is unreliable; a large voltage shift occurs especially when negative gate bias is applied due to adsorption/desorption of gas molecules. Although passivation of the TFTs is used to overcome such instability, previously proposed passivation materials did not improve the reliability. Here, we show that the In2O3 TFTs passivated with Y2O3 and Er2O3 films are highly reliable and do not show threshold voltage shifts when applying gate bias. We applied positive and negative gate bias to the In2O3 TFTs passivated with various insulating oxides and found that only the In2O3 TFTs passivated with Y2O3 and Er2O3 films did not exhibit threshold voltage shifts. We observed that only the Y2O3 grew heteroepitaxially on the In2O3 crystal. This would be the origin of the high reliability of the In2O3 TFTs passivated with Y2O3 and Er2O3 films. This finding accelerates the development of next-generation displays using high-mobility In2O3 TFTs.

Reference: P. R. Ghediya, Y. Magari*, H. Sadahira, T. Endo, M. Furuta, Y. Zhang, Y. Matsuo, and H. Ohta*, Preprint at  (2024).
(Invited) Integration and Optimization of 2D Transition Metal Dichalcogenides as Switching Layers in Memristors
Authors: Capasso Andrea
Published: December 2024

Memristive devices possess the ability to dynamically adjust resistance based on previous voltage and current inputs. They represent a frontier in next-generation computational hardware, offering unparalleled potential for brain-inspired computing and neuromorphic engineering. Among the various configurations, electrochemical metallization (ECM) memristors feature a solid electrolyte layer sandwiched between two electrodes and perform resistive switching via filament formation (SET) and dissolution (RESET) [1]. Recent studies have focused on the integration of two-dimensional (2D) materials into the design of ECM memristors, aiming at improving performance and unlocking new functionalities [2-4]. 2D transition metal dichalcogenides and hexagonal boron nitride, in particular, are promising candidates for realizing memristors with ultra-low switching voltages, suitable for neuromorphic computing and artificial synapses [5, 6].

In this talk, I will focus on vertical ECM memristor in crossbar configuration using chemical vapor deposited (CVD), atomic-thick MoSe2 as switching material, and Au/Cu as bottom/top electrodes. The devices exhibit nonvolatility and bipolar resistive switching behavior, with well-defined SET/RESET voltages (below 1V in absolute value) [7]. We performed atomic-scale investigations by transmission electron microscopy to unveil the filament formation mechanism within the MoSe2 layer. Our results shed light on the Cu/MoSe2 interface, particularly critical for memristor performance, providing key information on the intermixing and diffusion mechanisms of Cu atoms within the device structure.

Furthermore, we studied the effect of XeF2 fluorination of the MoSe2 films to tune their surface properties and improve the ion transport kinetics across the interface with Cu. By carefully controlling the XeF2 process, we were able to induce structural and chemical modifications in the MoSe2, such as layer thinning and doping/implantation. This could provide a way of controlling the interface morphology and ultimately the performance and reliability of the memristive devices. Transport properties and X-ray photoelectron spectroscopy analyses provided insights into the fluorination-induced modifications on the MoSe2 surface, offering a framework for performance optimization. Overall, these findings rationalize the 2D materials-based ECM memristor operation and highlight the potential for advanced applications.

References

[1] I. Valov et al., Nanotechnol., 22, 289502, 2011.

[2] R. Xu et al., Nano Lett., 19, 2411–2417, 2019.

[3] J. Jian et al., Adv. Electron. Mater., 8, 2022.

[4] Y. Shi et al., Nat. Electron., 1, 458–465, 2018.

[5] W. Huh et al., Adv. Mater., 32, 2002092, 2020.

[6] G. Cao et al., Adv. Funct. Mater., 31, 2005443, 2021.

[7] J. Fernandes et al., ACS Appl. Mater. Interfaces, 16, 1767–1778, 2024.
Thermal Conductivity Enhancement of Single Polyethylene Oxide Nanofiber
Authors: Nguyen Anh Tuan , Lee Woochul
Published: December 2024

Thermal management is vital in the development of various electronic and optoelectronic devices, including high-power integrated circuits. A temperature rise, often caused by inadequate heat dissipation, can significantly affect these devices, leading to decreased performance and reduced lifespan. Although metals are commonly used for thermal management, there has been a continuous search for materials that are lightweight, cost-effective to produce, and chemically stable. In this context, we have explored the thermal conductivity of polyethylene oxide (PEO) nanofibers, which were fabricated using the near-field electrospinning technique. Our research revealed that the thermal conductivity of PEO nanofibers (~3 W/m·K) is significantly higher than that of their bulk counterparts (0.2 W/m·K). This increase in thermal conductivity is attributed to the improved internal structure of the nanofibers, such as enhanced crystallinity and molecular orientation. Our findings highlight the potential for using polymers like PEO nanofibers in applications that require high thermal conductivity, including electronics packaging, energy storage, and thermal interface materials.
Periodically Strained 2D Materials for Tunable Optoelectronic Applications
Authors: McLean Mitchel , Nguyen Anh Tuan , Lee Woochul , Gaillard Nicolas
Published: December 2024

An expansion in the domain of thin and flexible electronics has led to advances in strain engineering, and particularly strain induced in atomically flat two-dimensional (2D) semiconductors. An array of physical properties has been shown to be modified through strain in 2D materials, including but not limited to carrier mobility, band gap energy, and band gap type. Due to their large aspect ratio, strain can be imparted both macroscopically (“long-range strain”) as well as at the nanoscale (“short-range strain”). Periodic short-range strain allows for band gap modulation which modifies the local optical absorption spectrum over the 2D material. The overarching goal of this work is the characterization of such strained 2D systems using patterned metallic layers to induce periodic optoelectronic properties.

In this communication, we report on our progress in producing patterned metal (Au, Ag) and metal-oxide substrates which serve as a basis for imparting periodic short-range strain in 2D materials (MoS2, MoSe2). The synthesis of these substrates is accomplished by first creating a metal pattern on a silicon dioxide/silicon substrate using a combination of lithography, laser ablation, and/or deposition processes, followed by an annealing process which results in nanometer-scale hemispherical islands that are then used as a support for suspended, strained 2D semiconductors. We employ a variety of characterization techniques to study the structural and electrical properties of the systems, including Raman spectroscopy, atomic force microscopy (AFM), conductive AFM, Kelvin probe force microscopy, and scanning electron microscopy. We aim to compare experimental optoelectronic data with results from a density functional theory strain model calculated using topographic information as input parameters.
Solution-Based Processing of Two-Dimensional Materials for High-Performance and Wafer-Scale Electronics
Authors: Kim Jihyun , Kang Joohoon
Published: December 2024

The integration of two-dimensional (2D) materials into practical electronics has been hindered by the lack of scalable fabrication methods. To overcome the limitation, I will introduce a general approach for wafer-scale electronics based on 2D nanomaterial inks, which is fabricated by molecular intercalation-assisted exfoliation method, enabling highly uniform, ultrathin, phase-pure, and large lateral size 2D nanoflakes. This approach enables the printing of large-area thin films characterized by effective van der Waals (vdW) sheet-to-sheet contacts, which promote a clean interface and minimal charge trapping states. We demonstrate the versatility of the printed thin films by integrating them with various electrical functionalities—dielectric, semiconducting, and metallic—resulting in vdW thin-film devices that exhibit exceptional performance over large scales. These devices not only enhance current electronics but also expand potential applications to include photodetectors, diode, and logic gates, demonstrating their broad utility in advanced electronic systems.
(Invited) Progress in 3D-Oriented MOF Systems
Authors: Falcaro Paolo
Published: December 2024

Metal-organic frameworks (MOFs) are promising materials for a variety of applications including sensing, microelectronics, and optics. Despite their exceptional functional properties, protocols for the microfabrication of MOF-based components are still underdeveloped. However, this is a key-enabling process: controlling the geometrical position, shape, and crystal orientation in micropatterns will enable the implementation of MOF materials in technologically relevant devices.[1]

In this presentation, we will discuss recent developments in the field of 3D-oriented MOF systems;[2,3,4] specific attention will be given to those procedures using ceramics as precursor materials. Protocols for the deposition of 3D-oriented polycrystalline Cu-based MOFs via hetero-epitaxial growth from Cu-based ceramics will be presented.[2,3] A recent strategy that enables the expansion of photolithography for the microfabrication of 3D-oriented MOF patterns will be examined.[4,5] Films and patterns of 3D-oriented MOFs show polarization-dependent fluorescent properties.

References

[1] P. Falcaro, D. Buso, A.J. Hill, C.M. Doherty, Adv.Mater.
2012, 24(24):3153–68; M. Linares‐Moreau, L. A Brandner, M. de J Velásquez‐Hernández, J. Fonseca, Y. Benseghir, J.M. Chin, D. Maspoch, C. Doonan, P. Falcaro Adv.Mater.
2024, 36, 2309645

[2] P. Falcaro, K. Okada, T. Hara, K. Ikigaki, Y. Tokudome, TA.W. Thornton, A.J. Hill, T. Williams, C. J. Doonan, M. Takahashi Nat. Mater.
2017, 16(3), 342-348.

[3] M. Linares-Moreau, L. A. Brandner, T. Kamencek, S. Klokic, F. Carraro, K. Okada, M. Takahashi, E. Zojer, C. J. Doonan, P. Falcaro, Adv. Mater. Interf.
2021, 8, 2101039.

[4] M.d.J. Velásquez-Hernández, M. Linares-Moreau, L.A. Brandner, B. Marmiroli, M. Barella, G.P. Acuna, S.D, Zilio, M.F.K. Verstreken, D.E. Kravchenko, O.M. Linder-Patton, J.D. Evans, H. Wiltsche, F. Carraro, H. Wolinski, R. Ameloot, C. Doonan and P. Falcaro. Adv.Mater.
2023, 35, 2211478.

[5] M.Tu, B. Xia, D.E. Kravchenko, M. L. Tietze, A. J. Cruz, I. Stassen, T. Hauffman, J. Teyssandier, S. De Feyter, Z. Wang, R. A. Fischer, B. Marmiroli, H. Amenitsch, A. Torvisco, M. de J. Velásquez-Hernández, P. Falcaro & R. Ameloot Nat. Mater., 2020, 20, 93–99

Figure 1
(Invited) air/Liquid Interfacial Formation Process of Electrically Conductive Metal-Organic Framework Nanosheets
Authors: Makiura Rie
Published: December 2024

Development of rational methods for creating ordered two-dimensional (2D) structures with nanometer scale precision is one of the central issues in the nanoscience and nanotechnology fields because of their intrinsic physical-chemical properties which are seen in those of their equivalent bulk state. Inclusion of highly regulated nanopores into the nanosheet structure will further open the possible applications such as nanosieves, molecular/ion storage and sensor devices as well as introducing guest molecules into the nanopores tune variedly the sheet properties (electric conduction, nanoheterojunction). Utilizing molecular building units are suitable for creating such porous nanosheets because of rich variety of design and facile modification of size and shape.

Here, I present a facile bottom-up synthesis of molecular nanosheets with both positional and size regulated nanopores utilizing air/liquid interfaces[1-5]. By applying liquid interfaces, growth direction of the object can be well controlled with utilizing self-assembly feature of the molecules under mild conditions. We have succeeded to tune finely the nanosheet structures by rational modification of molecular building units . The highly crystalline structure remains after transferring a solid substrate from the liquid surface as well as without any supports. Notably, such highly oriented porous crystalline structure is obtained specifically by applying bottom up synthesis at air/liquid interfaces, not by other techniques.

I also present detailed insights into the formation process of electrically conductive MOF nanosheets composed of 2,3,6,7,10,11-hexaiminotriphenylene (HITP) and Ni(II) ions (HITP-Ni-NS) at the air/liquid interface [6-8]. The morphological and structural features of HITP-Ni-NS strongly depend on the standing time—the time without any external actions involved, but leaving the interface undisturbed after setting the ligand solution onto the metal-ion solution. We find that the fundamental features of HITP-Ni-NS are determined by the standing time with conductivity sensitively influenced by such pre-determined HITP-Ni-NS characteristics. These findings will lead towards the establishment of a rational strategy for creating MOF nanosheets at the air/liquid interface with desired properties, thereby accelerating their use in diverse potential applications.

1. R. Makiura et al. Nature Mater. 9, 565 (2010).

2. S. Motoyama, R. Makiura, O. Sakata, H. Kitagawa, J. Am. Chem. Soc. 133, 5640 (2011).

3. R. Makiura, O. Konovalov, Sci. Rep. 3, 2506 (2013).

4. R. Makiura et al. ACS Nano, 11, 10875–10882 (2017).

5. R. Makiura et al, Coord. Chem. Rev. 469, 214650 (2022).

6. R. Makiura et al, ACS Appl. Mater. Interfaces, 13, 54570 (2021).

7. R. Makiura et al, J. Colloid Interface Sci. 651, 769 (2023).

8. R. Makiura et al, Langmuir. 39, 8952 (2023).

Figure 1
Highly Flexible Electrochromic Devices Containing Photo-Curable Acrylated Viologens
Authors: Eom Sooyeon , Park Jong Seung
Published: December 2024

Electrochromic technology enables colorimetric modulation via external voltage control, driven by electron movement and reversible redox reactions. Although inorganic metal oxides provide stability, they exhibit restricted color changes confined to single-layer arrangements. Organic materials, particularly viologens, have garnered attention for their multi-color capabilities and ease of preparation. In this study, we synthesized photo-curable viologen derivatives displaying red, green, and blue hues with enhanced adhesion from acrylate end groups. We fabricated single-layer electrochromic devices (ECDs) by combining these viologens with polymer-based electrolytes. All three colors exhibited large optical contrast (over 80%), high cyclic stability (300 cycles), and moderate switching (within 20 s). Furthermore, the electrode modification was carried out by applying a coating layer of fluorinated carbon nanotubes (FCNTs). The performances of flexible ECDs were significantly improved by incorporating FCNT-modified electrodes, which led to excellent cycling stability (>300 cycles) and swift switching. We also obtained flexible and even stretchable electrodes made up of PDMS substrates with silver nanowires and PEDOT:PSS. By spray-coating FCNT to enhance flexibility and performance, the prepared flexible ECDs demonstrated a large transmittance difference, stability for extended cycles, and consistent operation. The current studies suggest promising applications in smart windows and cutting-edge wearable electrochromic devices.
(Invited) Color e-Paper Technology with Electrochemistry Toward Energy Conservation
Authors: Kobayashi Norihisa
Published: December 2024

Multifunctional electrochromic (EC) materials which control multiple colors, various color density, and specular reflection are expected to be potential candidate for light-modulation device and novel reflective display device. Electrodeposition is also attractive method to create colors1-6) because silver (Ag) nanoparticles exhibit various optical states based on their localized surface plasmon resonance (LSPR). LSPR bands of metal nanoparticles are affected by the size and shape. The control of LSPR, therefore, must enable dramatic changes in color for the surface where nanoparticles are deposited. We successfully demonstrate the first LSPR-based multicolor EC device enabling reversible control of six optical states—transparent, silver mirror, cyan, magenta, yellow and black. We will discuss the mechanism of electrodeposition and a wide range of its applications.

References; 1) Adv. Mater., 24, 122 (2012), 2) Adv. Mater., 25, 3197 (2013), 3) Chem. Mater., 26, 6477 (2014), 4) Nanoscale,
12, 23975 (2020), 5) Adv. Mater. Tech., 6, 200081 (2021), 6) Sol. Ener. Mater. & Sol. Cells, 251, 112 (2023).
2D Ga2S3 Heterostructured Catalyst with Highly Enhanced Photocatalytic Activity
Authors: Chen Chih-Yen
Published: December 2024

In contrast to most composite nanostructured catalysts, two-dimensional Ga2S3 semiconductors and ultrathin graphitic-related materials, g-C3N4 heterojunction photocatalysts, are highly efficient photocatalysts for the removal of methylene blue from aqueous solutions because of their extraordinarily stable absorption and physical and optoelectrical properties. The activities of Ga2S3 nanosheet catalysts are 40% higher than those of commercial P25-TiO2 catalysts. In comparison with the performances of Ga2S3 and g-C3N4 photocatalysts, light absorption by the Ga2S3/g-C3N4 heterostructures in the visible region was at least 2.53 and 2.97 times higher, and their photocatalytic efficiencies increased by more than 2.23 and 2.96 times, respectively. The efficient separation and prolonged lifetimes of photogenerated charge carriers enhanced the photocatalytic activity for degradation. In addition, the parameters of the synthesis process for finely uniform, promising Ga2S3/g-C3N4 heterostructured nanomaterials were investigated; such parameters included the precursor amount (Ga, S, and melamine), annealing temperature, and reaction time, and their effects on the structural properties and photocatalytic performance were studied. The detailed mechanism of the photocatalytic system was evaluated through a free radical scavenging experiment, electron paramagnetic resonance spectroscopy, and time-resolved fluorescence spectroscopy. Pseudo-first-order kinetics models were used to describe the efficient photocatalysis of methylene blue photodegradation by the Ga2S3/g-C3N4 heterostructures over different reaction times. e−, •OH, and •O2
– radicals were confirmed as the major reactive oxidative species, and the degradation products were determined. This study is beneficial because it will promote future research on the use of renewable, sustainable resources in photocatalytic applications.