bluuebunny/crossref_metadata_2025 huggingface dataset:
Inverted Glasses As Ductile Lithium Ion Conductors for Solid State Batteries
Authors: Kalnaus Sergiy , Westover Andrew S , Yang Guang , Kornbluth Mordechai , Herbert Erik , Dudney Nancy
Published: August 2024

Inorganic electrolytes for solid state batteries with Li metallic anodes must combine properties such as high ionic conductivity, chemical stability, and resistance to failure due to propagation of Li dendrites. Abundance of experimental evidence suggests that cracking of the solid electrolytes due to pressure exerted by lithium plating into the material defects is the primary source of failure [1]. This is due to inherent brittleness of the ceramic ionic conductors, i.e. their inability to reduce stress by means other than fracture. Unlike ceramics, plastic deformation in glass can be achieved via shear and (or) by densification. Both mechanisms can be operational in glasses with reduced content of glass formers relative to the content of glass modifiers – i.e. inverted glasses. Using the example of lithium phosphorous oxynitride, Lipon, we demonstrate how these two mechanisms are capable of accommodating applied stress while avoiding creation of new surfaces by cracking. We investigate the resistance to fracture in Lipon-like glasses and the underlying connection to their composition via instrumented nano-indentation, Raman spectroscopy, and numerical simulations. We observe enhancement of isochoric shear with increase of Li content, similarly to the reports of increased plasticity in sodium aluminoborate glases with high alkali content [2]. Nano-indentation demonstrates that Lipon is extremely resistant to fracture, compared to other inorganic solid electrolytes [3].

[1] Porz, T. Swamy, B.W. Sheldon, D. Rettenwander, T. Fromling, H.L. Thaman, S. Berendts, R. Uecker, W.C. Carter, Y.-M. Chiang, Mechanism of lithium metal penetration through inorganic solid electrolytes. Adv. Energy Mater. 7, 1701003 (2017)

[2] Sellappan, T. Rouxel, F. Celarie, E. Becker, P. Houizot, R. Conradt, Composition dependence of indentation deformation and indentation cracking in glass. Acta Mater. 61, 5949–5965 (2013)

[3] Kalnaus, A. Westover, M. Kornbluth, E.J. Herbert, N.J. Dudney, Resistance to fracture in the glassy solid electrolyte Lipon. J. Mater. Research, 36, 787-795 (2021)
Functional Protective Coatings Based on Polysaccharides and Single-Ion Conducting Polymers for Li Metal Batteries
Authors: Vargas Ordaz Mariana , Gastaldi Matteo , Gerbaldi Claudio , Gaberscek Miran , Dominko Robert
Published: August 2024

This work aims to study a protective coating based on cellulose and P(LiMTFSI) single-ion conductor polymer and its effects on Li metal anode stability and reversibility. The strategy used involves the physical mixture of the aforementioned polymers to enhance the electrochemical performance through Li-ion flux homogenization at the Li metal surface, promoting the formation of a dense plating. Single-ion conducting polymers (SICPs) are incorporated due to their beneficial effects such as enhancing lithium ion transport, boosting lithium transference number (𝑡𝐿𝑖
+), and diminishing the effects of concentration polarization, avoiding the initiation and propagation of high surface area lithium (HSAL). Furthermore, a quasi-solid-state Li metal battery system is explored which brings additional advantages over the typically used organic electrolytes. In this sense, during this study we propose using the protective coating based on cellulose and P(LiMTFSI) to tailor an adequate interphase that creates a good adhesion, by taking advantage of the polymers film formation ability, and therefore improving the lifespan and safety of the battery. The coating effectiveness is tested by casting the solution on an activated lithium surface and performing lithium platting/stripping protocols in Li/Li and Li/Cu pouch cells under selected current densities (0.5, 1 and 2 mA/cm2). Complementary electrochemical tests are carried out to study transport, conductivity parameters, and its performance in full cell coupled with LFP cathode. Finally, we analyze the correlation with the physicochemical properties and electrochemical performed based on spectroscopic techniques and microscopy to study the most relevant parameters influencing a high Coulombic Efficiency.

Acknowledgments

This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska – Curie Grant Agreement N° 945357, and co-financing from the Slovenian Research and Innovation Agency (ARIS) is fully acknowledged.
Ex Situ Synthesis of Ti3C2@Fe-Ni-NC Heterostructure Towards an Efficient Bifunctional Electrocatalyst for High-Performance Zinc-Air Batteries
Authors: Gopalakrishnan Mohan , Kao-ian Wathanyu , Limphirat Wanwisa , Yonezawa Tetsu , Mohan Gopalakrishnan
Published: August 2024

Zinc-air batteries (ZABs) with sustainable electrocatalysts have seen a lot of efforts to address oxygen reaction challenges to increase their lifespan and energy efficiency. Metal-organic frameworks (MOFs) and their derived materials are potential bifunctional electrocatalysts for addressing the oxygen reactions kinetics. However, under operational circumstances, MOFs and derived materials typically exhibit subpar electrochemical and conductivity. In this study, embedding MOF derived FeNi-N-C porous material in a few layer MXene nanosheets was effective strategy, enabling adequate conductivity, stability, and exposure number of active sites with better electrocatalytic activity towards oxygen reduction and oxidation reactions (ORR and OER). The resulting FeNi-NC@Ti3C2 hybrid exhibits notable bifunctional activities with a half-wave potential of 0.85 V and a low overpotential of 1.56 V, remarkable long-term cycle durability, as well as strong alcohol tolerance in an alkaline electrolyte. In addition, there is conductive MXene scaffold to achieve the highest ORR and OER activities with an ΔE value of 0.70 V. Furthermore, the FeNi-NC@Ti3C2 air-cathode-based assembled ZAB exhibits remarkable long-term cycling stability at 10 mA cm-2, a peak power density of 201 mW cm-2, and a high open circuit voltage (OCV) of 1.5 V. Ti3C2 MXene nanosheets provide a synergistic effect between two different materials in addition to protecting the surfaces of composite. This work provides a useful technique for enhancing ZAB's oxygen redox reactions, which could be used to aid in the development of efficient MOF@MXene based catalysts for electrochemical energy reactions.
One-Step Fabrication of Semi-Transparent Nanofibrous Lithium-Ion Battery
Authors: Mentbayeva Almagul , Tatykayev Batukhan , Shalabayev Zhandos , Bakenov Zhumabay
Published: August 2024

Flexibility and transparency of batteries greatly expand their application and offer new opportunities to electronic devices making them foldable, bendable, and not obstracting. Herein was proposed a facile and beneficial strategy to solve “hot” issues of such type of batteries by providing a uniform and stable framework for bendable, portable and semi-transparent "all-in-one" lithium-ion batteries (LIBs). The “all-in-one” flexible LIB was fabricated by one-stage electrospinning of PEO and PVDF-HFP-based precursor solution loaded with active materials. The electrochemical performance of the anode and cathode membranes was investigated in lithium half cells. To improve the electron-conductivity, CNTs were introduced inside the nanofibers in anode and cathode parts. The nanofibers containing active materials were successfully fabricated with the use of pre-synthesized nanosized LFP/C and graphite powders and loading them into the electrospinning solutions of the cathode and anode, respectively. The use of the same polymer to produce all three parts of the battery (anode, separator and cathode), as well as optimized electrospinning conditions, made it possible to obtain all-in-one flexible solo membrane. The concept was based on the application of nanofibers containing pre-synthesized active materials without carbonization, sintering or any other post-treatment. The developed “all-in-one” membrane assembled within copper and nickel meshes acting as anodic and cathodic current collectors demonstrated semi-transparency as can be seen from the figure. It is enabled by the swollen polymer fibers network, which provides transparent substrate for nano-sized particles of active materials. Additionally, the thin metallic mesh used as current collectors could maintain the overall transparency of the cell. Alternatively ITO glass and/or membrane with high content of CNT were used as a current collectors to provideimproved transparency and flexibility.

Acknowledgment

This research is funded by the Committee of Science of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. BR21882402)

Figure 1
(Invited) Stereoselective Synthesis of Molecular Nanographenes
Authors: Martin Nazario , Buendía Manuel , Fernández-García Jesús Manuel , Perles Josefina , Filippone Salvatore
Published: August 2024

Chirality is an important and fascinating concept which has not been properly addressed in carbon nanoscience [1]. We have previously reported the first inherently chiral bilayer nanographene with a helicene linker, both as the racemate and the M isomer [2,3]. Helical bilayer nanographenes (HBNGs) are chiral π-extended aromatic compounds consisting in two π-π stacked hexa-benzocoronenes (HBC) joined by a helicene, thus resembling van der Waals layered 2D materials. Recently, we have synthesized and compared [9]HBNG, [10]HBNG and [11]HBNG helical bilayers endowed with [9], [10] and [11]helicenes embedded in their structure, respectively. Interestingly, the helicene length defines the overlapping degree between the two HBCs (number of benzene rings involved in π-π interactions between the two layers), being of 26, 14 and 10 benzene rings, respectively, according to the X-ray analysis [4]. More interesting, this overlapping also controls the properties.

Compounds constituted only by carbon atoms, such as optically active molecular nanographenes have, so far, been obtained as racemates followed by time-consuming chiral chromatographic separations. In this presentation, an enantioselective strategy of a new bilayer nanographene which uses two pivotal stereocontrolled key synthetic steps to introduce and extend stereogenic elements into a polycyclic aromatic Csp2-based structure will be discussed. The resulting helical core of six ortho-fused rings embedded in the nanographene ensures stereochemical stability and good chiroptic activity [5].

Acknowledgements

: This work has been supported by the Ministerio de Educación, Cultura y Deporte of Spain (Grant PID2020-114653RB-100).

References

[1] J. M. Fernández-García, P. J. Evans, S. Filippone, M. A. Herranz, N. Martín, “Chiral Molecular Carbon Nanostructures”, Acc. Chem. Res. 2019, 52, 1565-1574.

[2] P. J. Evans, et al., Angew. Chem. Int. Ed. 2018, 57, 6774 –6779.

[3] Z. Zhou, J. M. Fernández-García, et al.
Angew. Chem. Int. Ed.
2022
, 61, e20211574.

[4] Patricia Izquierdo-García,et al. J. Am. Chem. Soc.
2023, 145, 11599-11610.

[5] M. Buendía-Mateos, et al. Manuscript submitted,
2023.
(Invited) Spironanographenes: Chemospecific Scholl Reaction, Unexpected Formation of Bilayers and Donor-Acceptor Behavior
Authors: Fernández-García Jesús Manuel , Izquierdo-García Patricia , Lión-Villar Juan , Martin Nazario
Published: August 2024

Bottom-up benchtop synthesis of nanometric fragments of graphene, molecular nanographenes (NGs), allows the design and monodisperse preparation of molecules with structures, and thus properties, at will. The most commonly employed methodology has mainly consisted in the π-extension of a central scaffold followed by a graphitization step, in which the honeycomb pattern of the final molecular nanographene is formed. The vast majority of syntheses involving molecular nanographenes, employ the Scholl reaction as graphitization step. This dehydrogenative C–C coupling, first described by Roland Scholl in 1910, has now become one of the most powerful reactions in NGs synthesis, although its mechanism pathway is still under debate.

In this connection, in early 2023, we reported a chemospecific Scholl reaction depending on the electronic nature of the central scaffold. The formation of stabilized trityl cations using anthracene as central scaffold, led to the formation of spirocycles under Scholl reaction conditions, without interrupting the graphitization process, for the first time (Figure a).1 In contrast, the destabilization of the trityl cation by including fluorine atoms afforded helically arranged NGs (Figure b).2

Furthermore, in order to study the electronic communication in spironanographenes, recently we have extended the π-system of spirobifluorene yielding to two-fold chiral spironanographenes (Figure c). Surprinsingly, the π-π interactions of the graphitic moieties avoid their orthogonal disposition yielding a bilayer that could lead to important electronic features due to the overlap of the two fragments (Figure d).3

[1] P. Izquierdo-García, J. M. Fernández-García, J. Perles, I. Fernández, N. Martín. Angew. Chem. Int. Ed. 2023, 62, e202215655

[2] P. Izquierdo-García, J. M. Fernández-García, I. Fernández, J. Perles, N. Martín. J. Am. Chem. Soc. 2021, 143, 11864–11870.

[3] P. Izquierdo-Garcia, J. M. Fernandez-Garcia, S. Medina Rivero, M. Samal, J. Rybacek, L. Bednarova, S. Ramirez-Barroso, F. J. Ramirez, R. Rodriguez, J. Perles, D. Garcia-Fresnadillo, J. Crassous, J. Casado, I. G. Stara, N. Martin, J. Am. Chem. Soc.
2023, 145, 11599.

Figure 1
(Invited) Carbon Phase Adjustment by Multi-Configuration Ligand in Endohedral Metallofullerene Derivatives Gd@C82(morpholine)7 Under High Pressure
Authors: Yao Huanli , Yao Haodong , Li Xiaodong , Zhao Lina , Sun Baoyun
Published: August 2024

Metallofullerenes present an ideal research object for developing new carbon structures with improved properties under high pressure. In this presentation, high pressure investigation is realized on metallofullerene derivatives (Gd@C82(morpholine)7) by applying in situ synchrotron XRD, Raman, and IR spectroscopy, combined with high pressure density functional theory (DFT) calculations. The regulations of multi-configuration morpholine ligands avoid the direct collapse of the carbon cages commonly happened to fullerenes, making the fine structure transformation possible for the first time, including ligand configuration exchange, anisotropic shrinkage of cage, new constructed bonds, and even the encaged metal’s movement with increasing pressure. The charge-transfer principle as the beneath driving force of structural transition is found. These findings demonstrate that multi-configuration ligand maps an innovative strategy for phase transition control of metallofullerenes under high pressure, thus providing deep insight, step by step, into the phase transition mechanism of these hybrid molecular systems on molecular level.
(Nanocarbons Division Poster Award, 2nd Place) Rare-Earth Families of Metallofullertubes or Metallofullerenes?
Authors: Davidson Tanisha , Stevenson Steven
Published: August 2024

In our quest to isolate larger carbon cage fullertubes (e.g., C90-C130), we have explored the effect of adding metal atoms to the plasma of an electric-arc reactor. In the extracted metal-containing soot, we observe the typical array of Gd@C2n, Gd2@C2n, and Gd3N@C2n endohedral metallofullerenes that have been characterized for decades. However, upon addition of aminopropanol to the extracted endohedral soot, we are able to observe interesting metallo-carbon clusters which have not yet experimentally isolated or characterized (i.e. unknown structures). In this presentation, I will discuss our recent findings from 4 rare-earth families of endohedral species (e.g., Er, Gd, Lu, Ho).
Distinct High-Pressure Responses of Halide Perovskites from Bulk to Low Dimension
Authors: Yin Tingting
Published: August 2024

Hybrid organic-inorganic perovskites (HOIPs) are low-cost and highly efficient optoelectronic and photovoltaic materials for applications in solar cells, light emitting diodes (LEDs), and so on, which is correlated with their intrinsic structures. Now the hybrid perovskite families include three-dimensional (3D) (CH3NH3PbBr3), two-dimensional (2D) ((C4H9NH3)2(CH3NH3)n-1PbnI3n+1) and nanostructured ((CH3NH3PbBr3 nanoparticles) materials. Herein, well understanding the relationship between the cystal structures and the related functional properties of HOIP materials is essential to the application point of view. High pressure up to gigapascal, offers a comprehensive way to study the structure-property correlation of solid materials in the atomic level, where both crystal structures and electronic properties are changed dramatically.

In this presentation, high pressure induced dramatically inorganic and organic part changes in 2D HOIPs are comprehensively studied[1,2], as shown in Figure 1. On the other hand, structural phase transition and morphology changes are also explored in 3D HOIP and their nanoparticles[3], as shown in Figure 2. All the high pressure-induced inorganic structural transition is resolved by in situ X-ray powder diffraction (XRD) measurements, morphology change is resolved by transmission electron microscopy (TEM), the correlated optical responses are investigated by absorption and photoluminescence spectroscopy. And the rotational isomerism is evidenced by the vibrational properties of the organic BA chain by Raman spectroscopy combined with the Ab initio calculations.

Reference:

[1] T Yin, B Liu, J Yan, Y Fang, M Chen, WK Chong, S Jiang, J-L Kuo, J Fang, P L, S-H W, K-P Loh, T-C Sum, T J. White, and Z Xiang, J. Am. Chem. Soc. 141, 1235 (2019).

[2] Yin T, Yan H, Abdelwahab I, Lekina Y, Lü X, Yang W, Sun H, Leng K, Cai Y, Shen Z, Loh KP, Nat. Commun. 14, 411 (2023).

[3] T Yin, Y Fang, WK Chong, KT Ming, S Jiang, X Li, J-L Kuo, J Fang, T-C Sum, T J. White, J Yan, and Z Xiang, Adv. Mater. 30, 1705017 (2018).

Figure 1
Elucidating the Impact of the Dielectric Environment on Excitons and Trions in 2D Semiconductor Electrodes
Authors: Tews Austin , Almaraz Rafael , Sambur Justin
Published: August 2024

Transition metal dichalcogenides (TMDs) (MX2; M = Mo, W; X = S, Se) are a promising class of materials for photoelectrochemical solar energy conversion applications due to their optimal bandgaps and natural abundance. In this configuration, TMDs are placed onto a conductive substrate and employed as a photoelectrode. A key step in the solar energy conversion process is to photo-excite the semiconductor and dissociate the photogenerated excitons to drive a reaction of interest (e.g., H2 evolution). Because these materials are so physically thin, the excitons are sensitive to the local environment. In this work, we characterize the exciton and trion formation behavior as a function of solvent dielectric, ionic strength, and chemistry. As the dielectric constant of the solvent decreases, trion formation increases. The lower dielectric solvent causes lower Coulombic screening, increasing the probability that an exciton will encounter another electron to generate a trion. I will discuss how these findings relate to a working photoelectrochemical cell.
(Invited) Electronic Doping in Two-Dimensional Semiconductors
Authors: Blackburn Jeff , Hermosilla Palacios Martha Alejandra , Ferguson Andrew J
Published: August 2024

Quantum-confined semiconductors provide highly tunable optical and electrical properties for a wide variety of emerging applications. Two-dimensional semiconductors possess tunable bandgaps, high charge carrier mobilities, and strong light-matter interactions that can enable applications in photovoltaics, quantum information processing, and spintronics. Electronic doping, the intentional introduction of controlled charge carrier density and type (electrons or holes) is a fundamental enabler for many emerging applications of two-dimensional semiconductors. While electrostatic doping in transistor geometries is useful for certain applications, it is important to develop additional methods based on e.g. molecular redox doping and substitutional atomic doping that can provide tunable Fermi level control in the absence of an applied bias. In this presentation, I will discuss our efforts to develop such doping strategies for a variety of two-dimensional semiconductors. I will discuss how electronic doping modulates opto-electronic properties, including ground-state absorbance, charge transport, and excited-state dynamics in these 2D semiconductors. These studies provide fundamental insights into the degree to which molecular and substitutional doping strategies can modulate Fermi level, charge transport, and excitonic optical transitions in 2D semiconductors.
(Invited) Electrical, Optical, and Mechanical Properties of Two-Dimensional Materials
Authors: Perebeinos Vasili
Published: August 2024

Atomically thin two-dimensional materials are direct bandgap semiconductors with a rich interplay of the valley and spin degrees of freedom, which offer the potential for electronics and optoelectronics. A strong Coulomb interaction leads to tightly bound electron-hole pairs or excitons and two-electron one-hole quasiparticles or trions. We solve the two-particle and three-particle problems for the wavefunctions for excitons and trions in the basis set of the model- Hamiltonian for single particles. The calculated linear absorptions, photoluminescence spectra, and polariton spectra as a function of doping and temperature explain the experimental data in 2D monolayers and predict novel spectroscopic features due to the many-body Coulomb interactions. Exciton lifetime plays a crucial role in optoelectronic applications. I will also discuss the phonon-assisted Auger non-radiative decay mechanism of excitons in doped 2D materials. Finally, I will discuss the strain engineering in monolayer 2D materials transferred on 1D and 2D patterned substrates. This material is based upon work supported by the Air Force Office of Scientific Research under award number FA9550-22-1-0312.
(Digital Presentation) Graphene as Barriers to Prevent Phosphoric Acid Leaching in High-Temperature PEMFCs
Authors: Liu Zimeng , Ji Zhaoqi
Published: August 2024

High-temperature PEMFCs running at 120-200℃ with the simplified water management has attracted more attention [1]. However, phosphoric acid molecules in polybenzimidazole membrane electrolyte (PA/PBI) are easily leaching to electrodes, which block pores of carbon fiber electrodes and impact gas transfer. Finally, the power density and durability of PEMFCs are extremely reduced [2].

Graphene is a kind of two-dimensional (2D) structure of honeycomb lattice material and can block the penetration of almost all molecules and atoms, which is able to prevent PA molecules leaching as [3]. Our group has investigated a nitrogen-modified reduced graphene oxide (NrEGO) prepared by the electrochemical exfoliation, which has shown excellent performance in enhancing the activity and stability of catalysts [4]. Meanwhile, our previous research developed a single layer graphene loaded electrode. The power density of high-temperature PEMFCs is improved compared with commercial cells after accelerated stress test [5].

Therefore, this work used NrEGO flakes as barriers to prevent phosphoric acid leaching to gas diffusion layer with lower Pt loading. In the present results, when the ratio of NrEGO and CB is 2 to 3 and the Pt loading is 0.25 mgPt/cm2, the cell improves 20% of the maximum power density and shows more stable with a decay of voltage by only 0.02 mV/h, which is quiet lower compared with that of 1.14 mV/h in commercial Pt/C.

References

[1] J. Lobato, H. Zamora, J. Plaza, P. Canizares, M.A. Rodrigo. Enhancement of high temperature PEMFC stability using catalysts based on Pt supported on SiC based materials. Applied Catalysis B: Environmental. 2016. 198: 516-524.

[2] Z.M. Guo, M. Perez-Page, J.N. Chen, Z.Q. Ji, S.M. Holmes. Recent advances in phosphoric acid-based membranes for high-temperature proton exchange membrane fuel cells. Journal of Energy Chemistry. 2021. 63: 393-429.

[3] S. Hu, M. Lozada-Hidalgo, F. C. Wang, A. Mishchenko, F. Schedin, R. R. Nair, E. W. Hill, D. W. Boukhvalov, M. I. Katsnelson, R. A. W. Dryfe, I. V. Grigorieva, H. A. Wu, A. K. Geim. Proton transport through one-atom-thick crystals. Nature. 2014. 516: 227-230.

[4] Z.Q. Ji, J.N. Chen, M. Pérez-Page, Z.M. Guo, Z.Y. Zhao, R.S. Cai, M. T.P. Rigby, S. J. Haigh, S. Holmes. Doped graphene/carbon black hybrid catalyst giving enhanced oxygen reduction reaction activity with high resistance to corrosion in proton exchange membrane fuel cells. Journal of Energy Chemistry. 2022. 68: 143-153.

[5] J.N. Chen, J. J. Bailey, L. Britnell, M. Perez-Page, M. Sahoo, Z. Zhang, A. Strudwick, J. Hack, Z.M. Guo, Z.Q. Ji, P. Martin, D. J.L. Brett, P. R. Shearing, S. M. Holmes. The performance and durability of high-temperature proton exchange membrane fuel cells enhanced by single-layer graphene. Nano Energy. 2022. 93: 106829.

Figure 1
Surface Modification of Prussian White Cathode to Improve Air and Cycling Stability in Sodium-Ion Batteries
Authors: Thomas Charlotte , Garman Kaitlin , Flitz Evan Summerwill , Singstock Nicholas Ryan , Ban Chunmei
Published: August 2024

Sodium (Na)-ion batteries (NIBs) are promising alternatives to lithium-ion batteries, because they use abundant and inexpensive sodium-based raw materials and have similar manufacturing processes to lithium-ion batteries. Prussian White (PW) cathodes in NIBs rival the lithium iron phosphate cathode for lithium-ion batteries; they have high energy density, tunable redox potentials, and they are inexpensive and easy to synthesize. Despite their benefits, PW materials are hygroscopic and suffer structural instability associated with the adsorption of water. Additionally, side reactions with and dissolution into the electrolyte can cause PW cathode degradation during cycling. While the synthesis of PW for NIBs often requires acidic conditions that evolve HCN, we have developed a neutral aqueous synthesis method for an iron-manganese based PW cathode that uses non-hazardous, inexpensive materials. Furthermore, surface modifications including metallic doping were studied to better understand the impact that surface stabilization has on the electrochemical behavior of PW cathodes. In this study, we have employed characterization techniques including X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, inductively coupled plasma-atomic emission spectrometry, and x-ray photoelectron spectroscopy, as well as extensive electrochemical testing to study how our synthesis and post-synthesis modifications impact the performance of PW cathodes. We show that our PW cathodes have improved stability against moisture and improved cycling stability.
Electrochemistry of 2D Nanosheets Based on Platinum Group Metals
Authors: Sugimoto Wataru , Muramatsu Keisuke , Takimoto Daisuke
Published: August 2024

Electrocatalysts and electrode materials based on platinum group metal (PGMs) and thier oxides are one of the most well studied materials for energy storage and conversion applications.1,2 As such materials are scarce, downsizing is critical for practical applications and various nanomaterials have been synthsized so far. 2D nanostructures (nanosheets) are particularly promising, owing not only to the high surface/volume ratio, but also to the stability originating from the 2D extended bonds. This talk will attempt to provide a summary of state-of-the-art PGM nanosheets and a critical assessment on the possible applications of such innovative nanomaterials. We will present and discuss recent advancement on the synthesis and structure-property relation of PGM oxide nanosheets based on RuO2 and IrO2 for supercapacitor3-5 application as well as electrocatalysts.6,7 In addition, electrocatalytic activity of Pt and core-shell Pt nanosheets will be presented.8-11

1. W. Sugimoto, Electrochemistry, 86, 281–290 (2018) DOI: 10.5796/electrochemistry.18-6-E2668.

2. W. Sugimoto and D. Takimoto, Chem. Lett., 50, 1304–1312 (2021) DOI: 10.1246/cl.210087.

3. W. Sugimoto, H. Iwata, Y. Yasunaga, Y. Murakami, and Y. Takasu, Angew. Chem. Int. Ed., 42, 4092–4096 (2003) DOI: 10.1002/anie.200351691.

4. K. Fukuda, T. Saida, J. Sato, M. Yonezawa, Y. Takasu, and W. Sugimoto, Inorg. Chem., 49, 4391–4393 (2010) DOI: 10.1021/ic100176d.

5. K. Sonobe, S. Tominaka, and W. Sugimoto, J. Am. Chem. Soc., 144, 15008–15012 (2022) DOI: 10.1021/jacs.2c05951.

6. D. Takimoto, K. Fukuda, S. Miyasaka, T. Ishida, Y. Ayato, D. Mochizuki, W. Shimizu, and W. Sugimoto, Electrocatalysis, 8, 144–150 (2017) DOI: 10.1007/s12678-016-0348-4.

7. D. Takimoto, Y. Ayato, D. Mochizuki, and W. Sugimoto, Electrochemistry, 85, 779–783 (2017) DOI: 10.5796/electrochemistry.85.779.

8. K. Fukuda, J. Sato, T. Saida, W. Sugimoto, Y. Ebina, T. Shibata, M. Osada, and T. Sasaki, Inorg. Chem., 52, 2280–2282 (2013) DOI: 10.1021/ic302720d.

9. D. Takimoto, T. Ohnishi, J. Nutariya, Z. Shen, Y. Ayato, D. Mochizuki, A. Demortière, A. Boulineau, and W. Sugimoto, J. Catal., 345, 207–215 (2017) DOI: 10.1016/j.jcat.2016.11.026.

10. J. Nutariya, E. Kuroiwa, D. Takimoto, Z. Shen, D. Mochizuki, and W. Sugimoto, Electrochim. Acta, 283, 826–833 (2018) DOI: 10.1016/j.electacta.2018.07.005.

11. D. Takimoto, S. Toma, Y. Suda, T. Shirokura, Y. Tokura, K. Fukuda, M. Matsumoto, H. Imai, and W. Sugimoto, Nat. Commun., 14, 19 (2023) DOI: 10.1038/s41467-022-35616-4.
Fast-Kinetics Electrochemcial Charge Storage by 2D Layered Materials
Authors: Yu Minghao
Published: August 2024

Electrochemical energy storage technologies have garnered significant attention due to their efficient and sophisticated approaches for storing, transporting, and supplying energy derived from sustainable resources.[1-2] The demand for power and energy supply is crucial in practical applications and is poised to expand further in the future. Hence, there is a pressing need to either design new electrode materials or intelligently reconstruct existing ones for energy storage devices to address the power-energy tradeoff effectively. In this presentation, I will highlight our recent endeavors in the exploration of 2D layered materials for sustainable energy storage applications.[3] Specifically, I will outline various interlayer engineering strategies developed for inorganic 2D layered materials. These strategies aim to regulate ion transport behaviors and enhance the power-energy performance of the assembled energy storage devices.[4-7]

References:

[1] Yu et al., Chem. Soc. Rev. 2021, 50, 2388-2443.

[2] Yu et al., Joule 2019, 3, 338-360.

[3] Yu et al., J. Am. Chem. Soc. 2020, 142, 12903-12915.

[4] Yu et al., Angew. Chem. Int. Ed. 2021, 60, 896-903.

[5] Yu et al., Nat. Commun. 2020, 11, 1348.

[6] Yu et al., Adv. Mater. 2022, 34, e2108682.

[7] Yu et al., Adv. Energy Mater. 2023, doi: 10.1002/aenm.202302961.
3D Printable Mxene for Chemoresistive Sensing
Authors: Song Kenan , Thummalapali Sri Vaishnavi , Fonseca Nathan
Published: August 2024

The demand for smaller microenvironments in modern electronics has prompted a search for new solutions, with the MXene (Mn+1XnTx) family emerging as a strong candidate due to its unique properties. This research focuses on incorporating microelectronics into micropatterned structures using cost-effective methods, opening up possibilities for smart devices and microsystems. The study details the synthesis and processing of titanium carbide (Ti3AlC2)-based MXene nanoparticles, with a novel in situ etching method to create multi-layered MXene (Ti3C2Tx) nanosheets. Water-based Ti3C2Tx inks in various concentrations were examined, and 3D printing was used to create micropatterned MXene layers with anisotropic electrical properties and energy storage potential, making them promising for 3D printable devices.
Tuning Van Der Waals Heterostructure of WS2/SrTiO3 Via in Situ Transmission Electron Microscopy
Authors: Lin Chih-Yen , Sung Hsin-YA , Lin Yu-Chuan , Yang Jan-Chi , Wu Wen-Wei
Published: August 2024

Monolayer two-dimensional (2D) materials have been widely researched and discussed in recent years, while multi-layers have received comparatively less attention. Nowadays, combining different materials to create heterostructures has become mainstream. In semiconductor industry, heterostructure can form devices such as lasers, light-emitting diodes, fast transistors and so on. Heterostructures can create well electronic properties by combining two different materials together. Therefore, heterostructures become a great tool to manipulate the electronic structures. In traditional heterostructures, the interfaces between two different materials are formed by covalent bonds, hence it requires similar lattice constants and structures. On the other hand, novel van der Waal heterostructures (vdW-heterostructure), formed by 2D materials, do not require the same strict similarity as traditional ones. VdW-heterostructures, which create 3D structures through van der Waals forces, provide a new perspective. In this study, we created a vdW-heterostructures by stacking tungsten disulfide (WS2) with single-crystal strontium titanate, SrTiO3 (STO), shown in Figure 1a,b. The crystalline atomic-layer WS2 and STO were synthesized by chemical vapor deposition (CVD) and pulsed laser deposition (PLD), respectively. They are analyzed by high-resolution transmission electron microscope (HRTEM) shown in Figure 1c-h. Once the vdW-heterostructures are formed, we conducted in situ heating by TEM. Through the advanced in situ technique, we observed the change of the twisted stacking angle by heating the vdW-heterostructure. Ultimately, the lattices will shift and rotate, minimizing the free energy, so that the vdW-heterostructure will be aligned and formed epitaxially. In addition, we utilized atomic resolution scanning transmission electron microscope (STEM) to identify the stacking images and the moiré pattern of the vdW-heterostructure. During the rotation, we can observed different moiré patterns by various twisted stacking angles. These different moiré patterns can produce different electrical properties, which can be applied to advanced semiconductor devices.

Keywords: high-resolution TEM/STEM, in situ heating, 2D materials, van der Waal heterostructures, moiré pattern

Figure 1. The vdW-heterostructure of STO/WS2. a) The diagram showing that the formation process of WS2/STO vdW-heterostructures which have different twisted stacking angles. b) The low-magnification SEM image showing that the single crystal STO thin film is transferred onto the TEM heating chips. The circles in the middle are the observation windows for transmission electrons. c-e) HRTEM images. f-g) Diffraction patterns of HRTEM. c,f) Single crystal STO thin film with d-spacing (1−10) = 0.284 nm. d,g) Monolayer single crystal WS2 with d-spacing (−110) = 0.274 nm. e,h) WS2(red)/STO(yellow) vdW-heterostructure with stacking angle 3.6°.

Figure 1
(Invited) Drug Delivery System of Photoresponsive Donor-Acceptor-Linked Molecules to Mouse Retina
Authors: Murakami Tatsuya
Published: August 2024

Neurotransmission is mediated by electrical pulses that are generated by coordinated activation and deactivation of ion channels in the plasma membrane of neuronal cells. The ion channels control the plasma membrane potential (V
m) by influx/efflux of ions. In our retina, the V
m is controlled by light and photo-excitable ion channels in photoreceptor cells and voltage-dependent ion channels in neuronal ganglion cells, which transmit visual signal to the brain. In contrast, patients with visual impairment and blindness, e.g., with age-related macular degeneration, lose response to light due to irreversible elimination of photoreceptor cells. Therefore, restoring vision is potentially possible by direct photoexcitation of neuronal ganglion cells with photoresponsive V
m-controlling molecules. As one of such molecules, we have focused on donor-acceptor-linked molecules (D–A molecules) capable of photoinduced intramolecular long-lived charge separation [1–4]. In this symposium, I will introduce my recent research mainly on drug delivery system of D–A molecules to the retina in mice [5].

REFERENCES

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[2] Numata, T. et al., J. Am. Chem. Soc.
2012, 134, 6092–6095.

[3] Takano, Y. et al., Chem. Sci.
2016, 7, 3331–3337.

[4] Numata, T. et al., Cell. Physiol. Biochem.
2020, 54, 899–916.

[5] Fukuda, R. et al., Adv. Therap. 2023, 6, 2300186.
(Invited) Development of Bright and Stable Luminescent Radicals
Authors: Albrecht Ken
Published: August 2024

Luminescent radicals are gathering attention as fourth generation luminescent material for OLED applications and other applications such as bioimaging and quantum sensing.1,2 TTM (tris(2,4,6-trichlorophenyl)-methyl) radicals are the most popular luminescent radicals but suffer from low photostability. The attachment of donor units, such as carbazole, can enhance the photostability and increase the photoluminescence quantum yield (PLQY).3 In this lecture, recent results from our group will be presented, and methods to increase the PLQY and photostability of luminescent radicals will be discussed. 4,5,6

[1] Q. Peng, A. Obolda, M. Zhang, F. Li, Angew. Chem. Int. Ed.
2015, 54, 7091.

[2] X. Ai, E. W. Evans, S. Dong, A. J. Gillett, H. Guo, Y. Chen, T. J. Hele, R. H. Friend, F. Li, Nature
2018, 563, 536.

[3] V. Gamero, D. Velasco, S. Latorre, F. Lopez-Calahorra, E. Brillas, L. Julia, Tetrahedron Lett.
2006, 47, 2305.

[4] R. Xiaotian, W. Ota, T. Sato, M. Furukori, Y. Nakayama, T. Hosokai, E. Hisamura, K. Nakamura, K. Matsuda, K. Nakao, A. P. Monkman, K. Albrecht, Angew. Chem. Int. Ed.
2023, 62, e20230255.

[5] K. Matsuda, R. Xiaotian, K. Nakamura, M. Furukori, T. Hosokai, K. Anraku, K. Nakao, K. Albrecht, Chem. Commun.
2022, 58, 13443.

[6] K. Nakamura, K. Matsuda, R. Xiaotian, M. Furukori, S. Miyata, T. Hosokai,. K. Anraku, K. Nakao, K. Albrecht, Faraday Discuss.
2023, in press. DOI: 10.1039/D3FD00130J
(Invited) Role of the Energy Offset in the Charge Separation at the Donor: Acceptor Interface
Authors: Tamai Yasunari
Published: August 2024

The trade-off between the short-circuit current density and open-circuit voltage has been one of the largest bottlenecks for further improving the device performance of organic solar cells (OSCs). Therefore, understanding the limit to which the energy offset can be reduced and the physics underlying the trade-off relationship is crucial. This study provides a threshold energy that can ensure high charge photogeneration efficiencies for Y-series nonfullerene acceptor-based OSCs and discusses the role of the energy offset in charge separation. In this study, we used transient absorption spectroscopy to track the time evolution of electroabsorption caused by electron-hole pairs generated at donor:acceptor interfaces. We found that an insufficient energy offset led to not only slow charge transfer at the donor:acceptor interfaces, but also inefficient long-range spatial dissociation of the charge transfer states. Our findings highlight the importance of overcoming the trade-off between fill factor and open-circuit voltage for further improving the power conversion efficiency.
(Invited) Luminescent Coordination Complexes as a Molecular Probe in Supramolecular Organic-Inorganic Assemblies
Authors: Horiuchi Shinnosuke
Published: August 2024

Guest molecules entrapped in a confined space can show unusual chemical and physical properties because their behaviors are manipulated by multiple noncovalent interactions from the interiors of the space. Thus, it is important to understand the local environment in the confined space and noncovalent interactions between the guest molecule and the interiors for establishing a new molecular system based on the unusual chemical and physical phenomena from the trapped molecules. Photophysical properties of coordination complexes are easily adjusted by variation of metal ions and organic ligands, leading to a fine-tuning of their excited states related to photoluminescence. In particular, a charge-transfer excited state in the coordination complexes is an environment-sensitive feature and thus they will act as a molecular probe for elucidating a local environment around the complexes. Herein we confirmed the photophysical properties of IrIII complexes within a hydrogen-bonded hexameric capsule, which are derived from their mixed states of 3MLCT/3LLCT excited states. The photophysical properties of IrIII complexes were altered by the encapsulation within the hydrogen-bonded capsule, owing to the effective modulation of a local environment around the complex by noncovalent interaction. This result also provides us a better understanding of the internal space within the hydrogen-bonded capsule.

Figure 1
(Invited) Synthesis and Optical Properties of Circularly Accumulated Carbazole Oligomers
Authors: Takase Masayoshi
Published: August 2024

Carbazole oligomers were synthesized to elucidate the physical properties arising from the interaction between circularly accumulated carbazoles. Aromatic nucleophilic substitution reactions were used to synthesize the target compounds, in which carbazoles were substituted for benzene, naphthalene, and anthracene. Structure-property relationships were evaluated by single-crystal structure analysis, theoretical calculations, and optical measurements including ultrafast time-resolved spectroscopy.
(Invited) An Unsymmetrical 5,15-Disubstituted Tetrabenzoporphyrin: Effect of Molecular Symmetry on the Packing Structure and Charge Transporting Property
Authors: Yamada Hiroko , Miyazaki Kazuya , Matsuo Kyohei
Published: August 2024

One of the key issues in the development of organic field-effect transistor (OFET) materials is the improvement of charge mobility. Since charge mobility depends on intermolecular interactions in solid state, it is important to control the crystal structure. In the current mainstream OFET materials, such as acenes and heteroacenes, which have one-dimensionally (1D) extended polycyclic aromatic frameworks, the effect of substitution on the crystal structure has been intensively studied. On the other hand, some bulky (trialkylsilyl)ethynyl-substituted derivatives such as 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) have been known to afford brickwork packing. In comparison, two-dimensionally (2D) extended π-conjugated molecules tend to form a sandwich herringbone, a co-facial herringbone, and a 1D columnar structure, due to their enhanced π−π interaction. The molecular design strategy to control the crystal structure of two-dimensional (2D) π-extended organic semi-conductors has not been intensively explored.

We synthesized an unsymmetric tetrabenzoporphyrin derivative (TIPS-Ph-BP) to demonstrate the effect of molecular symmetry on crystal packing.1 An unsymmetric structure would make 2D π-stacking more stable than a one-dimensional (1D) columnar structure to counteract steric and electronic imbalance in the crystal. TIPS-Ph-BP formed an antiparallel slipped π-stacking and 2D herringbone-like structure as expected, but, it formed a dimeric herringbone packing consisting of slipped π-stacking in an antiparallel manner in the crystal. OFETs using TIPS-Ph-BP achieved the maximum hole mobility of 0.71 cm2 V-1 s-1 due to the partially 2D packing structure.

Although TIPS-Ph-BP gave dimeric herringbone packing, this strategy could be used to control the crystal structures of various 2D extended π-conjugated systems. Further modification of the porphyrin substituents is ongoing.

Reference

K. Miyazaki, K. Matsuo, H. Hayashi, M. Yamauchi, N. Aratani, H. Yamada, Org. Lett.
2023, 25, 7354-7358
(Invited) Development of Novel Wavelength-Selective Organic Semiconductors for Agrivoltaics and Transparent Phototransistors
Authors: Ie Yutaka
Published: August 2024

Development of organic semiconductors based on pi-conjugated systems for use in solar cells, field-effect transistors, light-emitting diodes, and phototransistors has become an active area of research because of the potential applicability of these materials to large-area, lightweight, and flexible devices. Another advantage of such organic materials is the ease of tuning the molecular properties, which can be realized by versatile molecular design in organic chemistry. In this contribution, we will focus on the development of green-light or near-infrared wavelength-selective organic semiconductors, which can be applied to agrivoltaics and organic phototransistors, respectively.
(Invited) Fast Room-Temperature Phosphorescence of Organic Molecules: Mechanism and Molecular Design
Authors: Tani Yosuke
Published: August 2024

The mechanism and molecular design for fast and efficient room-temperature phosphorescence of organic molecules in solution will be presented.
(Invited) Interfacial Coupling between Nanostructures and Molecular Chromophores
Authors: Lubert-Perquel Daphne , Martinez Marissa , Feingold Benjamin , Pompetti Nicholas , Beard Matt C , Blackburn Jeff , Johnson Justin
Published: August 2024

The combination of nanostructures with molecular chromophores offers new opportunities to control excited-state photophysics and photochemistry for several potential applications and has fundamental interest for tuning the exciton states that lie at the interface. Semiconductor quantum dots (QDs) are naturally decorated with molecular ligands that can be exchanged for those with tailored properties. We have chosen polyacene ligands with the potential to create and shuttle triplet photoexcited states across the surface of the PbS QDs with tunable rates and efficiencies. Changing the tetracene orientation and packing density with respect to the surface alters the states involved and the rate of energy/charge transfer. The mechanism of this process is unclear, and we present a systematic control of key variables to elucidate the important features of the hybrid system. We find transfer times varying from femtoseconds to nanoseconds, depending on the extent of coupling at the interfaces.

Similarly, two-dimensional materials such as transition metal dichalcogenides (TMDCs) can be combined with molecules to provide intimate contact between the two species. The molecular layer can influence the properties of the TMDC, including altering the exciton population and spin-valley relaxation time. Through control of a molecular layer thickness (i.e., vanadyl phthalocyanine) deposited onto monolayer tungsten diselenide (WSe2), we discover that hybrid exciton states undergo ultrafast decoherence if molecular layers are less than 10 nm thick. Thicker layers produce slower spin-valley relaxation, presumably through exciton dissociation that reduces exchange coupling but without hybridization that destroys the initial spin character in the WSe2. We further characterize this effect through temperature dependence and a suite of spectroscopic and structural experiments.