bluuebunny/crossref_metadata_2025 huggingface dataset:
Engineering Thin Films of Silicon Phthalocyanines for Organic Thin Film Transistors
Authors: Lessard Benoit
Published: August 2024

Metal phthalocyanines (MPc) show great promise as semiconductors due to their exceptional optoelectronic properties, high thermal and photochemical stability, and ability to be easily synthesized and functionalized for specific applications. The metal/metalloid ion in the center of the MPc ring can significantly influence the electronic, optical, and magnetic properties of the compound, as well as its solubility and stability. The majority of MPc, such as copper phthalocyanine (CuPc) are used as hole-transport materials (p-type) in organic electronics. Silicon phthalocyanines (R2-SiPc) are emerging semiconductors which predominantly moves electrons and have led to high performance n-type organic thin-film transistors (OTFTs). Their low synthetic complexity paired with their versatile axial group facilitates the finetuning of their chemical properties, solution properties and processing characteristics without significantly affecting their frontier orbital levels or their absorption properties. The crystal engineering and film forming characteristics of R2-SiPc semiconductors can be tuned through appropriate axial group functionalization, therefore facilitating their integration into both OTFTs and OPVs by solution processing or vapor deposition.

Our group has developed families of R2-SiPc and integrated them into OTFTs with an emphasis on thin film processing and engineering of the interfaces for improved device performance. We have established structure property relationships of the final device performance as a function of 1) R2-SiPc axial groups and peripheral groups, 2) surface chemistry and composition and 3) thin film deposition conditions. I will also be discussing our recent work using advanced film characterization such as polarized Raman microscopy and synchrotron based scanning transmission x-ray microscopy to evaluate the resulting films and optimize the OTFT performance.

Figure 1
Structural Diversity Enables Dramatic Changes in Photocatalytic Efficiency of Porphyrinosilica Particles in Chem-Bio Binary Applications
Authors: Lee Suk Joong
Published: August 2024

Because of their potential applications in catalysis, separation, and gas storage, porous materials such as metal–organic frameworks (MOFs), porous coordination polymers (PCPs), porous organic polymers (POPs), and polymers with intrinsic microporosity (PIMs) have received much attention. Various building blocks have been introduced with various functional groups. Among the various organic building blocks, porphyrin has become one of the most important building blocks for the construction of such materials witnessed by a wide range of molecular architectures using porphyrin derivatives with various applications. In addition, they are often used to modify the surface of porous silica materials such as SBA-15, MCM-41 and MCM-48, because these porous silica materials exhibit narrow pore size distributions, high thermal stability and easy accessibility.

In this presentation, a series of highly ordered mesoporous porphyrinosilicas akin to MCM-41 will be discussed, as novel recyclable heterogeneous photocatalysts, demonstrating their efficacy in the selective oxidation. Porphyrins are recognized as efficient photocatalysts for oxidation reactions, attributed to their capacity to generate reactive oxygen species (ROS). Integrating them into a mesoporous silica framework can mitigate self-degradation, thereby yielding an efficient catalytic system with an extended operational lifetime.
Morphology-Dependent Interaction between Tetraphenylporphyrins and a Metal Oxide Surface: Electronic Signature, Photo Physics, and Chemical Interaction
Authors: Bockstedte Michel
Published: August 2024

Porphyrin-substrate hybrid systems are the building blocks in a series of materials, such as organic light-emitting diodes, chemical sensors, dye-sensitized solar cells and catalysts. Functional layers and 2D nanostructures on surfaces enable sensors, and nanoscale optical and magnetic materials. 3D porphyrin structures are for instance used in controlling and manipulating light at subwavelength dimensions. Understanding and correctly describing the way molecules interact with the substrate and in thin-film structures gives a handle on geometrical and electronic device properties. Indeed, adsorption and film-formation have a relevant effect on the molecular electronic structure even in the absence of strong covalent bonding, namely in terms of level-alignment with substrate states in the former and polarization-induced renormalization of molecular band gaps in the latter.

Using the case of Co(II)-tetraphenylporphyrin (CoTPP) on the MgO(100), we shine light on the adsorption at morphology-related low-coordinated surfaces sites and the effect of multilayer film formation from a theoretical perspective in a frame work of hybrid density functional theory and many-body perturbation theory. We simulate the photoemission spectra for relevant adsorption sites as a fingerprint with distinct site-related features in both valence and core-level regions of the electronic structure that are also observed in experiments on MgO(100) films on Ag(100) and thus aid the identification of sites. Effects of the formation of porphyrin films on the electronic and optical properties will be outlined for H2TPP and MgTPP.

We also highlight the self-metalation of H2TPP at morphology-related low-coordinated sites. Metalation is an important pathway for functionalization of porphyrin-based organic-inorganic structures. We address the self-metalation mechanism using ab initio molecular dynamics simulation at room temperature. While H2TPP is mobile on the pristine surface as the steric hindrance by phenyl rings prevents the physisorption of the macrocycle at a specific site, step edges or kink sites provide anchor points exposing low-coordinated, reactive oxygen-sites to hydrogens of the macrocycle. We report a spontaneous proton transfer at these sites forming an intermediate complex before the metalation occurs. This highlights the role of low-coordinated surface sites for the chemical interaction with the porphyrin.
Developing Methods to Interrogate Nanomaterials in Action for Electrochemical Energy Conversion Reactions
Authors: Jaramillo Thomas F.
Published: August 2024

We are observing unprecedented growth in electrified processes at industrial scales for the production of fuels and chemicals. This includes the production of hydrogen, carbon-based molecules (e.g. CO, ethylene), and ammonia, among others. Nevertheless, a number of technical challenges remain in order to meet cost targets for these technologies to scale. Understanding nanomaterials under reaction conditions is essential to designing and developing systems with improved performance and durability, addressing key needs. This paper will describe efforts to understand electrified interfaces at the nanoscale, ranging from fundamental systems to applied systems, and doing so under relevant operating regimes. Methods include X-ray techniques to observe the chemical dynamics of catalysts, vibrational spectroscopy and neutron reflectometry to monitor electrified interfaces at the nanoscale, microscopy to observe mass transport and crystallization within porous media, and inductively coupled plasma mass spectrometry to quantitatively measure corrosion phenomena. The development and implementation of these in-situ/operando techniques are providing the insights needed to advance these emerging technologies towards more widespread commercialization.
Recent Fundamental Advances in Quality of High-Performance and Highly-Scaled Carbon Nanotube Transistors
Authors: Pitner Gregory
Published: August 2024

Recently a number of breakthroughs have been reported by our team in the component qualities of transistors built on Carbon Nanotube (CNT) channels. However, any emerging channel material which seeks to outperform established semiconductors for transistor logic applications has a substantial hill to climb, given the incredible capabilities of advanced Si-based logic technology platforms. This talk will first aim to frame our progress on Carbon Nanotube CMOS technology in the broader context of the value proposition and desired component qualities needed to realize practical impact in computing applications. Next, we will share advances in the fundamental building blocks for Carbon Nanotube transistors towards these targets including channel, contact, doping, and gate-stack modules. Finally we will describe new record CNT MOSFET performance milestones achieved by integrating best available device components for first time, which gives insight into the remaining performance limiters and future directions.

[1] G. Pitner, et al., "Building High Performance Transistors on Carbon Nanotube Channel," VLSI 2023.

[2] S. Li, et al., "High-Performance and Low Parasitic Capacitance CNT MOSFET: 1.2 mA/um at Vds of 0.75 V by self-aligned doping in sub-20 nm spacer," IEDM 2023.

[3] N. Safron, et al., "Low N-type Contact Resistance to Carbon Nanotubes in Highly Scaled Contacts through Dielectric Doping," IEDM 2023.

[4] H.-Y. Chiu, et al., "Self-Aligned Contact Doping for Performance Enhancement of Low-Leakage Self-Alignment Method for High-Density Aligned CNT Array," Advanced Materials Interfaces, 2023.

[5] T.A. Chao, et al., "Small Molecule Additives to Suppress Bundling in Dimensional-Liminted Self-Alignment Method for High-Density Aligned CNT Array," Advanced Materials Interfaces, 2023.

[6] Q. Lin, et al., " Band-to-Band Tunneling Leakage Current Characterization and Projection in Carbon Nanotube Transistors," ACS Nano 2023.

[7] Z. Zhang, et al., "Complementary Carbon Nanotube Metal-Oxide-Semicondcutor Field-Effect Transistors with Localized Solid-State Extension DOping," Nature Electronics, 2023.

[8] S.K. Su, et al., " Perspective on Low-Dimensional Channel Materials for Extremely Scaled CMOS," VLSI 2022.

[9] Z. Zhang, et al., "Sub-Nanometer Interfacial Oxides on Highly Oriented Pyrolytic Graphite and Carbon Nanotubes Enabled by Lateral Oxide Growth," ACS Applied aterials & Interfaces, 2022.

[10] G. Pitner, et al., "Sub-0.5 nm Interfacial Dielectrics Enables Superior Electrostatics: 65 mV/dec top-gated Carbon Nanotube FETs at 15 nm gate length," IEDM 2020.
Self-Calibrating Fluorimetric Analysis of Single-Wall Carbon Nanotube Samples for Electronics Applications
Authors: Cherukuri Tonya , Bachilo Sergei M. , Weisman Bruce
Published: August 2024

Semiconducting single-wall carbon nanotubes (SWCNTs) are a leading candidate to replace or supplement silicon in future generation chip manufacturing. Because they are produced as structural mixtures with varied electronic properties, SWCNTs must first be carefully sorted and purified. This requires new metrology tools that can reliably measure SWCNT sample compositions to guide sorting processes and confirm product purity. We describe here a novel, self-calibrating optical instrument designed for advanced characterization of SWCNT samples. This desktop system will quickly, sensitively, and non-destructively quantify the concentrations of multiple SWCNT (n,m) species. The key advance is adding variance spectroscopy to rapid excitation-emission fluorimetry. Variance spectroscopy is a recently developed method that can determine absolute concentrations of nanoparticles by analyzing statistical variations in the fluorescence signals from small volumes of dilute samples. Measurements are made by a small accessory module linked to a standard NanoSpectralyzer. It will automatically acquire and analyze variance spectra to find the sensitivity calibration factors needed to convert raw fluorescence intensities into actual concentrations of the different SWCNT species. Those measured calibration factors are valid for subsequent samples with similar processing histories, allowing rapid quantitation from quick excitation-emission scans. We expect that this analytical capability will support advances in basic carbon nanotube science and applications.
Towards Large-Area Black Phosphorous Midwave-IR Optoelectronics
Authors: Javey Ali
Published: August 2024

High-efficiency mid-wavelength infrared (mid-IR, 3–5 µm) optoelectronics, including light emitting diodes (LEDs) and photodetectors, are of high demand for emerging applications in spectroscopy, imaging, and gas sensing. Black phosphorus (bP) has emerged as a unique optoelectronic material for mid-IR applications with performances surpassing those of conventional III-V and II-VI semiconductors of similar bandgap. In this talk, I will present recent advancements on understanding and controlling the radiative and non-radiative recombination rates as a function of bP thickness. We observe higher photoluminescence quantum yields in bP as compared to conventional III-V and II-VI semiconductors of similar bandgaps due to the smaller Auger recombination rate. As a result, bP mid-IR LEDs with external quantum efficiency of >4% are reported, outperforming the state-of-the-art in this wavelength range. Furthermore, device encapsulation and packaging technologies are explored with extrapolated half lifetime of ~15,000 hours based on accelerated lifetime measurements. Finally, I will present strategies for large-area device fabrication and processing.
Advancing Aqueous Batteries: Harnessing Trivalent Indium for Superior Capacity, Efficiency, and Extended Cycle Life
Authors: Chang Songyang , Wu Xianyong , Florez Gomez Jose , Katiyar Swati , Morell Gerardo
Published: August 2024

Trivalent indium is distinguished by its unique three-electron In3+/In redox system and has a large capacity of approximately 700 mAh g−1, similar to that of metallic zinc. In addition, indium has a good redox potential (-0.34 V compared to standard hydrogen electrode) and no dendrite growth during the plating/stripping process, which allows In||Ti asymmetric cells to achieve 99.3% to 99.8% High Coulombic efficiency. Remarkably, its polarization in symmetric cells is only 1 mV, 1 to 2 orders of magnitude superior to reported metals. The effectiveness of trivalent indium extends to full-battery applications. Taking the In-MnO2 system as an example, the battery voltage reaches about 1.2 V, the capacity reaches about 330 mAh g−1, and the cycle life is extended to 680 cycles. This study highlights the potential of trivalent indium as an anode material characterized by high capacity, efficiency, low polarization, and extended cycle life, thereby providing a compelling trajectory for the advancement of aqueous battery technology.
Unveiling Reaction Mechanisms of Non-Aqueous Zn-Ion Batteries – Zn/LiFePO4 System
Authors: Kasemchainan Jitti , Kidkhunthod Pinit , Sinthong Sasisiri , Chinnakutti Karthik kumar , Gao Hongyi , Tapia-Ruiz Nuria
Published: August 2024

Zinc-ion batteries (ZIBs) are among the most promising energy storage technologies because of their low cost, safety, and environmental friendliness. In this work, we focus on investigating the electrochemical reaction mechanisms of ZIBs with Lithium iron phosphate (LiFePO4) as an active material in the positive electrode, Zn(OTf)2+LiCl dissolving Tetraethylene glycol dimethyl ether (TEGDME) as the electrolyte, as well as metallic Zinc as the negative electrode. After testing the ZIB cells by galvanostatic cycling, the cells with TEGDME exhibit the best electrochemical performance in terms of long-term stability. The initial specific discharge capacity is 118.3 mAh g-1 and the capacity retention is 91.4% after 100 cycles at a current density of 10 mA g-1. We propose the reaction mechanisms during the charge-discharge processes involve extraction/insertion processes of Li+ into/out of the olivine structure of LiFePO4 as evidenced by X-ray near-edge spectroscopy (XANES). According to X-ray diffraction (XRD) analysis of the discharged and charged LiFePO4 electrodes, the crystal structure changes from LiFePO4 to FePO4 when charging and back into LiFePO4 again when discharging. Besides, XRD and scanning electron microscopy (SEM) confirm that the cycled Zn electrode is hardly present with passivation and/or corrosion. Therefore, this new combination of Zn/LiFePO4 and TEGDME has a potential for ZIB applications.
On-Surface Photopolymerization - What Does the Surface Do?
Authors: Ringel Eva , Grossmann Lukas , Lackinger Markus
Published: August 2024

We attained the synthesis of mesoscale-ordered 2D polymers by the topochemical on-surface photopolymerization of fluorinated anthracene triptycene (fantrip) monomers. The underlying protocol is two-staged: (1) Self-assembly of the monomers into a photopolymerizable monolayer structure, where the photoactive anthracene moieties are face-to-face stacked; (2) cross-linking of the self-assembled monolayer into a covalent 2D polymer by photochemically excited [4+4] cycloadditions between the antiparallel aligned anthracene blades. Thereby, the long-range order attained in step (1) is transferred into the covalent state.

Yet, the topochemical approach depends crucially on achieving the reactive monomer packing with the appropriate mutual alignment of the anthracene blades. For this initial self-assembly, the underlying surface plays a decisive role, which also extends to the photopolymerization.

We show that the photoactive monolayer packing of fantrip monomers can be achieved on both alkane-passivated graphite and iodine-passivated Au(111) or Ag(111). Although the fantrip self-assembly appears essentially similar on these substrates, there are distinct differences in the subsequent photopolymerization. These can be rationalized by the photoexcitation of the substrate and the subsequent transfer of hot carriers to the molecular networks.

Nat. Chem. 13, 730-736 (2021)

Eur. J. Org. Chem. 2021, 5478–5490 (2021)

Trends Chem. 4, 471-474 (2022)

Angew. Chem. Int. Ed. 61, e202201044 (2022)
Mangenese Copper Selenide Nanosheet Arrays Derived from Metal-Organic Frameworks for Efficient Solid-State Asymmetric Supercapacitors
Authors: Alhammadi Ayoob , Bahaa Ahmed , Fetyan Abdulmonem , AlKindia Tawaddod , Susantyoko Rahmat Agung
Published: August 2024

Metal chalcogenide nanostructures, particularly metal selenides, have unique properties, such as high electrical conductivity, large specific surface area, exclusive porous networks, and exceptional electrochemical properties compared to traditional nanostructures.1
2 A novel strategy is proposed to design and fabricate hierarchical Manganese copper selenide nanosheet (MnCuSe NS) arrays from metal-organic frameworks (MOFs). The hierarchical MnCuSe NS arrays can deliver enriched electroactive sites and shorten the ion/electron diffusion pathways. When evaluated as positive electrodes for supercapacitor (SC), the MnCuSe NS electrode displayed remarkable electrochemical properties with ultra-high specific capacity of ≈350.4 mA h g−
1 and an areal capacity of ≈0.94 mA h cm−
2 at a current density of 3 mA cm−
2, exceptional rate capability (≈79.5% of the capacity retention at a higher current density of 50 mA cm−
2), and outstanding cyclic stability (≈95.4 % of capacity retention after 10 000 cycles). Most importantly, the assembled MnCuSe NS//FeMnO/NG solid-state asymmetric SC exhibited a wide operating potential window of 1.6 V with an ultra-high volumetric capacity of ≈2.4 mA h cm−
3 at a current density of 3 mA cm−
2, an excellent energy density of ≈71.6 Wh Kg−
1 at a power density of ≈794 W Kg−
1, and ultra-long cycle life (≈93.4 % of capacity retention after 10 000 cycles). This proposed method provides a general protocol to design and fabricate metal selenide nanosheet arrays with superior electrochemical energy storage properties and exceptional cyclic stability, holding significant potential for future energy storage devices in commercial aspects.

Keywords: Hierarchical, Metal-organic frameworks, Metal chalcogenide, Energy density, Asymmetric supercapacitors

Reference:

(1) Han, J. H.; Kwak, M.; Kim, Y.; Cheon, J. Recent Advances in the Solution-Based Preparation of Two-Dimensional Layered Transition Metal Chalcogenide Nanostructures. Chem. Rev.
2018, 118 (13), 6151–6188. https://doi.org/10.1021/acs.chemrev.8b00264.

(2) Karuppasamy, K.; Vikraman, D.; Hussain, S.; Kumar Veerasubramani, G.; Santhoshkumar, P.; Lee, S.-H.; Bose, R.; Kathalingam, A.; Kim, H.-S. Unveiling a Binary Metal Selenide Composite of CuSe Polyhedrons/CoSe2 Nanorods Decorated Graphene Oxide as an Active Electrode Material for High-Performance Hybrid Supercapacitors. Chemical Engineering Journal
2022, 427, 131535. https://doi.org/10.1016/j.cej.2021.131535.
Corrosion Initiation on Reinforcing Steel with Mill Scale in Mortar
Authors: Doi Kotaro , Hiromoto Sachiko
Published: August 2024

Corrosion of reinforcing steel rebar is the main cause of loss of the long-term reliability of concrete structures. When the rebar is corroded, the rust induces cracks and detachment of the cover concrete. The mill scale, a thick oxide film, is formed on the rebars when the rebar is hot rolled. The role of mill scale on the corrosion resistance of rebars in concrete has not been clarified, yet. This study studied the corrosion behavior of rebars with mill scale in mortar.

The samples are commercial rebars with 19 mm diameter, which have a mill scale of several tens of micrometers in thickness. The rebars without mill scale prepared by the electrolytic polishing were used as the comparison samples. A Hyperbaric-oxygen accelerated corrosion test (HOACT) [1] was carried out using the rebars embedded in the mortar with a 5.5 mm cover thickness. To prompt the breakdown of passive film on the rebars, 2.1 M NaCl solution was mixed with the mortar. In the HOACT, pressurized oxygen gas is supplied to the sample, and the oxygen reduction reaction on the steel surface is enhanced, leading to the steel's corrosion acceleration. The oxygen pressure was 0.6 MPa and the test period was 14 days. The corrosion of the rebar with a mill scale was more significant than that without a mill scale. This result shows that the mill scale reduces the corrosion resistance of the steel rebar in concrete [2].

To investigate the effect of the mill scale on the corrosion resistance of the rebar, anodic polarization measurements of the rebars with and without the mill scale were carried out in a saturated Ca(OH)2 solution containing Cl-. The pitting potential of the rebar with mill scale was more noble than that of the sample without mill scale. However, when the mill scale was scratched, the pitting potential was significantly shifted to the less noble direction, and it was below that of the rebar without the mill scale. These results show that the mill scale improves the corrosion resistance of the rebar in concrete, in contrast, the corrosion resistance of the rebar with a defective mill scale becomes even worse than that of the rebar without the mill scale [2].

[1] K. Doi, S. Hiromoto, H. Katayama, E. Akiyama, J. Electrochem. Soc., 165(9), C582-C589 (2018).

[2] K. Doi, S. Hiromoto, T. Shinohara, K. Tsuchiya, H. Katayama, E. Akiyama, Corrosion Science, 177, 108995 (2020).
(Invited) Visualizing Electrode Assembly Movement and Lithiation Gradients in Lithium-Metal Batteries
Authors: Abraham Daniel P.
Published: August 2024

In this presentation we will introduce dilatometry and profilometry using Operando Energy Dispersive X-Ray Diffraction conducted at the Advanced Photon Source, Argonne National Laboratory. This approach is applied to a Li metal battery with a high-voltage NMC811 cathode but the method is suitable for any and all materials and electrodes.

In the technique, micrometer-wide collimated X-rays traverse the electrode assembly, and the Bragg peaks from different crystalline phases are used to track the hard edges of the solid materials as they move due to volume changes in the cell. We visualize, with submicron resolution, the movement of the oxide cathode and microporous separator: the latter is observed through the diffraction of X-rays off the lamellae in the polymer matrix. One can map movement of the cathode and also compression in the porous separator – a task that is beyond the capabilities of mechanical dilatometers. We use our approach to show periodic expansion and contraction of metallic lithium during delithiation and relithiation of the cathode and to quantify formation of mossy lithium on the metal surface. The method is universal, easy to implement in-operando, and is selective in distinguishing between different phases in materials.

Another dividend of this method is that it allows the profiling of lithiation gradients in the layered-oxide cathode. In our NMC811/Li cells, the cathode gradients are seen even with weak currents, they occur only during relithiation of the cathode, and they persist as the currents abate during constant-voltage discharge.

Other particulars of our experimental approach and observations will also be discussed during the talk.

Acknowledgement: This document has been created by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357.
(Invited) From Solid-State Li-S to Polysulfide Flow Batteries: Challenges and Opportunities
Authors: Nanda Jagjit
Published: August 2024

Despite several decades of research and development work on Li-S batteries, there are still several fundamental issues that limits their performance and life. Controlling the polysulfide dissolution remains the major bottle neck in liquid electrolyte-based system. To alleviate this issue, there has been a steady progress in transitioning to quasi solid-state gel electrolytes and solid-state sulfur. The talk will cover some recent results on soft-chemistry approach by using a polymer gel electrolyte that has high ionic conductivity at RT and buffers volume changes during electrochemical activity. One example relates to fabrication a gel S-cathode on a carbon nanotube (CNT) matrix coated with a crosslinked network of polyethyleneimine -poly (ethylene oxide) (PEI-PEO), and solvated Li salt (LiTFSI). By optimizing the salt and polymer composition the conductivity of gel electrolyte exceeded 1x10-4 S/cm at RT. Design of high-performance solid-state sulfur cathode relies on effective ionic and electronic wiring with optimal composition of solid- electrolyte and electronic diluent such as carbon nanotube of highly graphitic carbon. Achieving high loading solid-state sulfur cathode is challenging due to limited ion-transport. The talk will cover recent work on catholyte design for sulfur cathodes using sulfide based solid electrolytes. In contrast, RT Li/Na polysulfide flow batteries provide a completely different geometry and architecture where the energy and power density is dictated by the solubility of the polysulfide species in the desired solvent and membrane design and stability.

Acknowledgment

This research is supported by Asst. Secretary, Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (VTO) through the Advanced Battery Materials Research (BMR) Program and Energy Storage Program, Office of Electricity, Department of Energy, USA.
Carbon Decorated MOF for Low-Cost Aqueous Al-Ion Supercapacitors: Effect of Redox Additives
Authors: Shegokar Shyamal Gopal , De Puja , Anshu Satvik , Mandal Debabrata , Chandra Amreesh
Published: August 2024

The performance enhancement of ZIF-67 based Al-ion supercapacitors using conductive additives is presented. By using the simple co-precipitation technique, the porous ZIF-67 and composites of ZIF-67 with two distinct forms of carbon rGO and CNS were synthesized. Physiochemical characterizations like XRD, BET, FTIR, etc., were performed to confirm the successful synthesis of ZIF-67 and its composites. The electrochemical measurements were performed in the three-electrode configuration using 0.5 M AlCl3 electrolyte. Out of all, the composite of ZIF-67 with rGO (ZIF-67_rGO) outperformed all other materials because of its larger specific surface area and enhanced electrical conductivity. Further, the electrolyte modification was performed in 6 mM KFCN as a redox additive for ZIF-67_rGO composite. Here, the specific capacitance of ZIF-67_rGO composite enhanced from 245 F g-1 to 346 Fg-1 at 1 A g−1 current density. Using the redox additive, we observe an increment of almost 41% in ZIF-67_rGO composite than its pristine counterpart. The composite also delivered good cycling stability with excellent coulombic efficiency of 89% and 95% after 1000 cycles, at 5 A g-1 current density, respectively.
Next-Generation Batteries through Advanced 3D Electrode and Material Concepts
Authors: Falkowski Viktoria , Reinhold Carolyn , Rist Ulrich , Sterzl Yannic , Pfleging Wilhelm
Published: August 2024

With the rise of renewable energy sources, energy storage solutions become increasingly important as they represent a key feature for secure and constant power supply. In this regard, battery systems play a crucial role in accelerating the transition towards sustainable and green energy sources. To meet the rising global demand, further advancement of the battery technology is imperative. One optimization pathway is to use battery materials that are more sustainable while also yielding improved electrochemical performance, contributing to both environmental and functional advancements. However, innovation must go beyond the material level, and new electrode design approaches for an efficient combination of high power and high energy systems are necessary.

In this context, the three-dimensional (3D) battery concept with its increased exposed electrode surface, shows a great promise for enhanced electrochemical performance compared to the conventional flat designs of state-of-the-art electrodes. Targeting at the bottleneck of high power/high energy density systems, the incorporation of micro-structured channels within the electrodes improves lithium-ion diffusion pathways and minimize strain from volume expansion during electrochemical cycling.

Our focus is the investigation of 3D electrode architectures generated by laser-processing techniques such as ultrafast laser ablation and laser-assisted printing. Working with ultrafast lasers offers the possibility to process materials while reducing thermal impact and allows the creation of well-designed and controllable electrode surface topographies. The adoption of this concept has already shown great impact in enhancing the high-rate capability and lifetime of conventional electrodes in lithium-ion batteries.[1-3]

Expanding the scope, this work explores the applicability of laser-generated 3D electrode architectures to next-generation battery active materials such as high-voltage lithium nickel manganese oxide (LNMO) composites. On anode side, silicon/graphite and amorphous carbon is extensively investigated for lithium-ion batteries and sodium-ion batteries, respectively. To understand the impact of the manufacturing process, electrochemical evaluations are complemented by findings from laser-induced breakdown spectroscopy, SEM-EDX, Raman measurements, and Auger electron spectroscopy.

In conclusion, this contribution highlights the promising advancements achieved by applying laser-generated 3D electrode architectures to next-generation battery materials and aims to provide valuable insights into this exciting frontier of battery research.

[1] W. Pfleging, Nanophotonics 7 (2018) 549–573.

[2] W. Pfleging, Int. J. Extrem.
Manuf. 3 (2021) 012002.

[3] M. Zaeh, Appl. Energy 303 (2021), 117693.
Modified Liquid Electrolyte with Porous Liquid Type-II for Lithium-Metal Batteries
Authors: Arzani Mehran , Singh Sakshi , Berry Vikas
Published: August 2024

Liquid electrolytes modified by adding type-II porous liquid (PL) were designed and prepared to study its effect on the performance of lithium-metal batteries. Porous liquids provide internal, permanent, and empty porosity which are capable of coordinating and transporting Li+. The potential of the porous liquid to capture and transport ions with high mobility leads to enhancement in battery performance. In this study, the physicochemical properties of electrolytes, mechanism of solvation, transport, and electrical conductivity of lithium ions through the new electrolytes will be presented, and the potential of the liquid electrolyte based on the type-II porous liquid to develop the battery performance was investigated. This modification effectively improved the Li ionic conductivity of the electrolyte because of the Li+ ion solvation by type-II PL. The dissociation of Li+-TFSI− ion pairs and the formation of complexes with Li+ ions (Li-PL) were improved by using the type-II PL, resulting in an increase in the ionic conductivity of the electrolyte. Our findings suggest that the use of PL electrolytes can be a good candidate for improvement in physicochemical properties of electrolytes leading to an enhancement in Lithium-Metal Batteries.
Interplay of Interphases in Lithium-Sulfur Cells
Authors: Bhargav Amruth , Robbins Victoria , Vanheusden Karel , Bugga Ratnakumar
Published: August 2024

Lyten’s revolutionary 3D Graphene is enabling the transition to a greener future through its high energy density lithium-sulfur (Li-S) batteries. As with all battery chemistries, the electrolyte-electrode interphases formed in-situ during cell cycling not only regulate the redox processes but also strongly dictate the cycle life of the cells.

In this talk, we will describe the different interphases formed on the cathode and anode of a Li-S battery and their importance. A glimpse into how regulating these interphases using different additives affects the cycle life of cells will also be demonstrated.
Moore's Law Scaling and Chemical Mechanical Planarization (CMP)
Authors: Prince Matthew Jon
Published: August 2024

Since the invention of the first integrated circuit in 1958, chemistry and materials have played a critical role in semiconductor process technologies, which has led to an exponential growth of transistors packed into circuits. Decades ago, Gordon Moore posited there would be a doubling of components every two years (revised from his original doubling every one-year prediction). This observation became known as Moore’s law.

As Denard scaling took on more complexity, the number of new materials used to build semiconductors increased at a torrid pace. The number of elements in the periodic table, used to fabricate devices, increased roughly five-fold from the 1980’s to the 2000’s.

In the earlier years, lithography, etch, thin films, implant, and diffusion were foundational technologies used to fabricate a silicon wafer into hundreds of microchips. In the late 1980’s a new technology Chemical Mechanical Planarization (CMP) was invented. It was developed out of necessity to reduce topography, critical for lithography’s depth of focus requirements. Without this key invention, patterning and building layer upon layer from front end transistors to back-end interconnects would not have been possible.

Intel implemented CMP into manufacturing in the early 1990’s on the 0.8 micron technology node which manufactured the 486 microprocessor. CMP was required to planarize dielectric oxide used to insulate the aluminum metal interconnects. Since then, the number of CMP applications over the last three decades has exploded, enabling the scaling of Moore’s Law.

CMP is not only used to improve lithography depth of focus. CMP also enables a method of metal interconnect and contact formation called damascene. Planarization is used to create dielectric isolation trenches, discrete plugs for insulation, aid advanced patterning architectures, build through silicon vias (TSVs), and enable complex wafer and chip bonding for die-to-die interconnects for disaggregated products.

Transistor scaling alone is no longer sufficient to meet device performance, power, and cost requirements. Complex material and architectural changes are required. And novel CMP applications continue to be added at each new technology node. This author will make an argument that CMP is critical to push scaling and enable future process nodes.

Figure 1
Evolving Preston’s Equation in Chemical Mechanical Planarization
Authors: Yang Jichul , Kobata Itsuki , Suzuki Kenichi , Kajita Shinji , Shiokawa Yoichi
Published: August 2024

The evolution of semiconductor devices necessitates greater control parameters for enhancing CMP process controllability. Historically, CMP engineers have sought to improve polishing process performance by real-time control of time, pressure, and velocity using Preston’s equation. However, Preston’s equation has traditionally addressed blanket-wafer or non-patterned wafer’s vertical or horizontal scale controllability, such as wafer center to edge or the in-wafer non-uniformity expressed by percentage. However, limited control variables cannot determine patterning profile changes.

Upon closer examination of the basic Preston’s equation, other factors were considered constant or environmental parameters, excluding pressure and velocity. Current and future scaled-down devices demand additional control parameters to achieve nanometer-scale vertical controllability with patterned wafers. This presentation introduces an extended Preston’s equation by incorporating more control parameters, including temperature and slurry concentration. The study reveals that lowering and controlling the polishing temperature induces slurry selectivity changes by modulating the activation energy between the slurry and wafer. This temperature control also drives pad material changes that impact selectivity. Furthermore, the study evaluates in-situ slurry composition control to assess its real-time impact on wafer performance. When all five active parameters are combined into the extended Preston’s equation, it is demonstrated that real-time nanometer vertical scaling is achievable. The results of this study provide insights into the future design direction of CMP equipment, which will be communicated in this talk along with the concept of future CMP equipment.
Towards Digital Twin Standards in Chemical Mechanical Planarization (CMP) for Advanced Packaging
Authors: Obeng Yaw
Published: August 2024

A digital twin is an integrated multi-physics, multiscale, probabilistic simulation of a system that uses the best available physical models, sensor updates, process history, etc., to mimic and to predict the performance of the system. In the semiconductor industry, there is a need to establish such fundamental, mechanism-based, correlations between process conditions and observed process performance. Such understanding can lead to the creation of industry-wide technical standards, and digital twins (i.e., real time digital replicas of unit processes), that will enable inter-operability, ease process selection and integration, as well as help reduced cost of ownership.

In this paper, we revisit our decades old, but still relevant, quest for appropriate mechanism-based metrology to support the digitization of Chemical-Mechanical Polishing (CMP) for the back-end-of line (BEOL), with advanced packaging, specifically hybrid bonding for 3D interconnects, in mind. Here, we consider the digitization of the nanoscale tribological aspects of CMP. For example, many CMP processes use chemically unstable polyurethane pads in a variety of slurry formulations which make the process difficult to understand and to model. We had previously described how the chemical instability of the PU-pads affects the CMP process performance. Here we contextualize the historical performance data, identify data gaps, and propose some next steps towards digital twin CMP modules.
(Invited) Epitaxial Growth of Quasi-Low Dimensional Materials for Novel Thermoelectric Films
Authors: Nakamura Yoshiaki
Published: August 2024

Thermoelectric conversion devices or modules with high performance have been expected for the electrical power generation from wasted heat. Then, thermoelectric materials with high dimensionless figure of merit zT at temperature T , described as S
2
σT/κ have been intensively sought, where S is Seebeck coefficient, σ is electrical conductivity, and κ is thermal conductivity. Therein, intercorrelation among three thermoelectric properties has been a big barrier against high zT. In conventional approach, the heavy elements such as rare metals are used because they inherently bring small κ in the materials. Now, ecofriendly ubiquitous element materials without toxic, rare, or high cost elements, showing high zT, are expected in the application view.

Introduction of nanostructures into materials is one of the promising ways to increase zT because of phonon scattering [1], quantum confinement effect in low dimensional materials and by energy filtering [2], and so on. Therein, structure design determines the properties, and then, this method can be expected to bring high zT in the ecofriendly and low-cost ubiquitous element materials. Furthermore, it is recently found that low dimensional materials and quasi-low dimensional materials such as layered materials with 2D structures in the unit cell show high zT values. Therefore, low and quasi-low dimensional materials for extraordinarily high zT values have been expected to be developed.

We have been developing a lot of kinds of well-controlled nanostructure films by SiO2 film technique. One of the examples: Si-based films including ultrasmall semiconductor nanodots with controlled interfaces, strains, crystal orientations, and compositions [3]. Furthermore, we have developed the epitaxial growth method of quasi-low dimensional material films composed of ecofriendly group IV elements on Si substrates: FeGeγ including 1D Ge helical structure and Ca-intercalated multi-layered silicene films. Here, we will introduce the epitaxial growth results of quasi-low dimensional material films. Epitaxial growth of FeGeγ films on Si were achieved by using Ge epitaxial nanodots as seed crystals[4]. In the case of Ca-intercalated multi-layered silicene, silicene bucked structure was found to be deformed. The deformation enhanced Seebeck coefficient. As a result, this sub-angstrom atomic displacement brought power factor enhancement while keeping high electrical conductivity [5]. In this talk, we will present the epitaxial growth process of quasi-low-dimensional material films on Si substrates for thermoelectric film devices composed of ecofriendly and low-cost thermoelectric materials .

[1] Y. Nakamura, et al., Nano Energy 12, 845 (2015).

[2] T. Ishibe, et al., ACS Appl. Mater. Inter. 10, 37709 (2018).

[3] Y. Nakamura, et al., Sci. Technol. Adv. Mater. 19, 31 (2018).

[4] T. Terada, Acta Materialia 236, 118130 (2022).

[4] T. Terada, et al., Adv. Mater. Inter. 9, 2101752 (2022).
Advancing Towards Commercialization with Enhanced Stability and Efficiency in Lithium Metal Batteries Using TTE as a Co-Solvent in Carbonate Electrolytes
Authors: Ha Chaeyeon , Kim Young-Jun
Published: August 2024

Lithium metal batteries are considered ideal anode materials for next-generation battery systems due to their high theoretical specific capacity (3,860 mAh g-1) and low negative electrochemical potential (−3.040 V vs. the standard hydrogen electrode), which are essential for high energy density. However, the fatal dendritic growth on the lithium metal surface, which occurs during repetitive cycling, acts as a significant barrier to commercially successful lithium metal battery application. Therefore, regulating the morphology of lithium plating in commercial carbonate-based electrolytes is a critical challenge for the stable operation of lithium metal batteries. Additionally, this leads to the formation of inhomogeneous lithium dendrites in carbonate-based electrolytes, manifesting as uneven current density and lithium-ion concentration gradients. The uneven current leads to inconsistent charging/discharging rates in the corresponding Ni-rich cathode, which in turn causes overpotentials and deteriorates cell safety, culminating in a reduction of capacity. this has been clarified through Kelvin probe force microscopy analysis to demonstrate an uneven state of charge distribution in the Ni-rich cathode.

In this work, we propose a new strategy for high-performance lithium metal batteries, utilizing 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) as a co-solvent with carbonate electrolytes. By using TTE as a co-solvent, we observed a reduction in the viscosity of the electrolyte, leading to improved ionic conductivity and a decrease in the overpotential during the lithium plating/stripping process via in-situ electrochemical atomic force microscopy. This resulted in more uniform Li deposition compared to conventional carbonate-based electrolytes, forming a dense and stable Li metal layer. Furthermore, by leveraging our control over stable lithium plating morphologies via TTE co-solvent system, we observed long-term cycling stability (capacity retention of 78% at 300 cycles) with the use of an ultra-thin Li layer (40 µm). Through these results, we have effectively enhanced the stability and efficiency of high-energy-density (380 Wh kg-1) electrodes based on carbonate electrolytes, and we believe that this study can contribute to the commercialization of lithium metal batteries.

Figure 1
(Invited) Tackling Interface Challenges for Shallow Diamond Color Centers
Authors: Choy Jennifer
Published: August 2024

Spin defects in wide-bandgap semiconductors, such as color centers in diamond, can be highly sensitive to local (nanoscale) changes in magnetic field, temperature, and strain. These solid-state quantum sensors have certain advantages over their atomic counterparts owing to their room-temperature operation without the need for vacuum components and the relative ease of photonic- and RF-component integration. However, near-surface quantum defects exhibit spin decoherence and most of the light emitted is trapped within the bulk crystal due total internal reflection at the interface. In this presentation, I will summarize our recent work towards better understanding and addressing these interface challenges, including the modeling and experimental characterization of radiative emission of near-surface emitters, design of nanophotonic components to improve light extraction, and surface analysis and chemical termination techniques aimed at improving spin coherence of emitters.