bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Post-Synthetic Modulation of 2D Semiconductors by Organic Materials
Authors: Kiriya Daisuke 
Published: December 2024

Modulation of materials is crucial for developing the physicochemical properties and applying them to devices. For transistors, the alignment of energy levels is critical; therefore, the corresponding modulation of carrier concentrations and material phases is a fundamental issue. In this talk, I will focus on the modulation of 2D semiconductors, known as transition metal dichalcogenides (TMDCs), to modulate electronic properties by interfacing with organic materials.
About a decade ago, we demonstrated molecular doping to a TMDC material, MoS2, to modulate the carrier concentration effectively and achieve a degenerately doped level [1]. Various molecules come out after the work. I would discuss the modulation of carrier concentrations of bulk and monolayer MoS2 by interfacing with organic materials from the point of transport behaviors and sensor applications [2].
In addition to the carrier modulation, we are tackling the modulation of phases of TMDCs. The usual semiconductive phase is known as 1H or 2H phase in the case of MoS2. If we can convert the crystalline phase to 1T/1T' phases, it would be interesting to apply it to electronics as a metallic material or quantum devices. Since the 1H and 2H phases are thermodynamically stable, it is not easy to convert MoS2 to 1T/1T' phases. I will show our current state of modulating the phases by applying chemical techniques.
[1] D. Kiriya, et al., Air-stable surface charge transfer doping of MoS2 by benzyl viologen, J. Am. Chem. Soc. 2014, 136, 7853.
[2] K. Matsuyama, et al., Metallic transport in monolayer and multilayer molybdenum disulfides by molecular surface-charge transfer doping, ACS Appl. Mater. Interfaces, 2022, 14, 8163; A. Fukui, et al., Unusual selective monitoring of N,N-dimethylformamide in a two-dimensional layered field-effect transistor, ACS NANO, 2023, 17, 14981.
Modulating Electronic Properties through Synthesis of Single-Layer Metallic Janus Crystal NbSSe
Authors: Sailus Renee , Tongay Sefaattin 
Published: December 2024

Janus crystals represent a family of 2D materials with structures that feature a metal cation between two different atomic species on the top and bottom faces. This unique structure with its broken mirror and inversion symmetry enables a host of fascinating quantum effects including formation of an internal electric field at the monolayer-limit, unique topological phases, and colossal polarization field. In particular, the metallic Janus crystal NbSSe is predicted to be a stable 2D polar metal of the kind theorized by Anderson and Blount and offers possible applications in nanoscale ferroelectric devices. In this talk I will introduce advances in realizing synthesis of metallic 2D Janus crystal NbSSe at Arizona State University. NbSSe is experimentally demonstrated via a surface-limited technique of plasma-driven atomic replacement at the surface to convert parent TMD crystals 1H-NbSe2 and 1H-NbS2 into 1T-NbSSe. Microscopic, topographical, and spectroscopic techniques are carried out to elucidate the structural transformation, air- and photo-stability, and electronic properties attributed to metallic Janus NbSSe1-6.
References

Anderson PW, Blount EI. 1965. Symmetry considerations on martensitic transformations: “Ferroelectric” metals? Phys. Rev. Lett. 14(7):217–219

Y. Qin, M. Sayyad, A. R.-P. Montblanch, M. S. G. Feuer, D. Dey, M. Blei, R. Sailus, D. M. Kara, Y. Shen, S. Yang, A. S. Botana, M. Atature, S. Tongay, Reaching the Excitonic Limit in 2D Janus Monolayers by In Situ Deterministic Growth. Adv. Mater.2022, 34, 2106222.

D. B. Trivedi, G. Turgut, Y. Qin, M. Y. Sayyad, D. Hajra, M. Howell, L. Liu, S. Yang, N. H. Patoary, H. Li, M. M. Petrić, M. Meyer, M. Kremser, M. Barbone, G. Soavi, A. V. Stier, K. Müller, S. Yang, I. S. Esqueda, H. Zhuang, J. J. Finley, S. Tongay, Room-Temperature Synthesis of 2D Janus Crystals and their Heterostructures. Adv. Mater.2020, 32, 2006320.

Fei, Z., Zhao, W., Palomaki, T.A. et al.Ferroelectric switching of a two-dimensional metal. Nature
560, 336–339 (2018). https://doi.org/10.1038/s41586-018-0336-3

Zhou, W. X. and Ariando Ariando. “Review on ferroelectric/polar metals.” Japanese Journal of Applied Physics 59 (2020).

Yagmurcukardes, M.; Qin, Y.; Ozen, S.; Sayyad, M.; Peeters, F. M.; Tongay, S.; Sahin, H., Quantum properties and applications of 2D Janus crystals and their superlattices. Applied Physics Reviews
2020,
7 (1).

Figure 1
(Invited) Metal Oxide Nanowire Array to Overcome Odor Sensing Limits
Authors: Nagashima Kazuki 
Published: December 2024

Toward developing advanced cyber-physical system (CPS), interest for a molecular recognition electronics is rapidly increasing for collecting chemical information in our daily life. Among various sensor technology, artificial olfactory sensor targeting on chemical data collection of odor is growing research field due to its promise in wide applications for non-invasive medical diagnosis, environmental monitoring, factory automation, security, smart agriculture, etc. In such applications, a lack of molecular sensing system having both material robustness and capability of molecular discrimination in complex mixtures has been a critical issue for the long-term collection of chemical information. Inorganic nanowires, especially for metal oxide nanowires, are a class of promising materials to overcome such issues due to their excellent material robustness in air and huge surface-to-volume ratio beneficial for effectively capturing and concentrating volatile molecules on their surface. Although a highly sensitive electrical detection of volatile molecules has been demonstrated using semiconducting nanowires up to date, poor understanding and design capability of molecule-to-surface interactions on nanowire surface have substantially limited their performance in artificial olfactory sensor systems which require molecular discrimination in complex mixtures.
In this presentation, we demonstrate that designing a coordination structure of ionic species at nanowire surface is of critical importance to control the adsorption, reaction and desorption properties of volatile molecules. The enhanced sensing performance and the molecular selective adsorption property of nanowire were successfully achieved as the results of designed surface coordination structure. In addition, molecular filter/molecular transport controller using nanowire array integrated with sensor device is conceptualized as novel artificial olfactory sensor system to discriminate molecules in complex mixture beyond the previous sensing limits.

References: ACS Sens.
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3, 10252 (2020) / Commun. Mater.
1, 58 (2020) / Nano Lett.
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19, 2443 (2019)
(Invited) 3D Oriented Metal–Organic Framework Dmof-1 Thin Films Functionalized with Azobenzene as Photo-Stimuli-Responsive Materials
Authors: Klokic Sumea , Amenitsch Heinz 
Published: December 2024

Profound knowledge on the structural transformations of photo-switchable Metal-Organic Framework films is fundamental to optimize their switching performance and to use them as stimuli-responsive materials.
In an epitaxial oriented DMOF-1-on-MOF film system [1] comprising azobenzene in the DMOF-1 pores (DMOF-1/AB) we studied the temporal evolution of the structural transformation after photo excitation. Therefore we employed time-resolved Synchrotron Grazing Incidence Wide-Angle X-Ray Scattering [2] and infrared measurements to track in depth the structural response of the DMOF-1/AB film upon altering the length of the azobenzene molecules by photo-isomerization (trans-to-cis, 343 nm; cis-to-trans, 450 nm). The DMOF-1/AB response occurred fully reversible and over several switching cycles by cooperative photo-switching of the entire oriented film within seconds [3].
For a deeper understanding of the switching behavior, we further investigated (i) the influence of substituting the terephthalic acid linkers in DMOF-1 with chloro-functionalized derivatives (Cl-DMOF-1) and (ii) enlarging its crystallite size with increasing growth times. Here, we could show that Cl-DMOF-1 reduces the structural flexibility, leading directly to a significantly slower response. In contrast, small crystallite sizes show entirely rigid frameworks (10-60 min) and more flexible ones with prolonged growth times (90 - 270 min) [4].
This work opens possibilities to tailor the functional behavior of light triggered mechanical storage systems e.g. [5].
References:
[1] M. Linares‐Moreau, L. A. Brandner, T. Kamencek, S. Klokic, F. Carraro, K. Okada, M. Takahashi, E. Zojer, C. J. Doonan and P. Falcaro, Adv. Mater. Interfaces, 2021, 8, 2101039.
[2] ) M. Burian, B. Marmiroli, A. Radeticchio, C. Morello, D. Naumenko, G. Biasiol, H. Amenitsch, J. Synchrotron Rad. 2020, 27, 51.
[3] S. Klokic, D. Naumenko, B. Marmiroli, F. Carraro, M. Linares-Moreau, S. D. Zilio, G. Birarda, R. Kargl, P. Falcaro and H. Amenitsch, Chem. Sci., 2022, 13, 11869–11877.
[4] S. Klokic, B. Marmiroli, D. Naumenko, G. Birarda, S. Dal Zilio, M. de J. Velásquez-Hernández, P. Falcaro, L. Vaccari and H. Amenitsch, CrystEngComm, 2024, DOI: 10.1039/D4CE00221K
[5] J. Wieme, S. M. Rogge, P. G. Yot, L. Vanduyfhuys, S.-K. Lee, J.-S. Chang, M. Waroquier, G. Maurin and V. Van Speybroeck, J. Mater. Chem. A., 2019, 7, 22663–22674.
(Invited) Investigating New Avenues for the Bulk Single Crystal Growth of BN
Authors: Metzger Florian , Dooley Jacob , Valenzuela Jonny , Sherpa Tenzin , Stoddard Nathan , Landskron Kai , Pimputkar Siddha 
Published: December 2024

Boron nitride (BN) is a fascinating ultra-wide bandgap semiconductor offering extreme material properties that can be leveraged in a range of potential applications including (opto-)electronic and quantum devices. Availability of high-quality, large-area and volume, single-crystal material would provide a significant boon to the community facilitating or enabling development of devices. BN has been successfully grown using high pressure, high temperature presses and precipitation from a solvent on the order of a few millimeters. While these methods have yielded high-quality material, scaling of these approaches is challenging motivating the search for additional bulk synthesis methods. This talk will present foundational work being performed in the pursuit of bulk BN growth using two industrial scalable methods: the ammonothermal method and a flux-based approach.
The ammonothermal method utilizes supercritical ammonia at temperatures and pressures around 400—600 °C and 100—250 MPa, respectively. One or more mineralizers are added to the solution to enhance the solubility of BN. This talk will demonstrate temperature-dependent solubility of BN in basic ammonothermal solutions containing alkali [1] and/or alkaline earth metals. Initial crystal growth experiments were performed using sodium as the mineralizer yielding the spontaneous nucleation and growth of sub-mm sized hexagonal and rhombohedral BN.
The flux-based method uses a solvent exhibiting exceptionally high solubility of nitrogen and boron. A dedicated growth system has been developed and initial growth runs have demonstrated the solubility and growth of BN from solution. Preliminary growth campaigns have successfully demonstrated the growth of ~ >0.1 mm sized BN crystals after 1-2 days.
This work has been supported by NSF DMR 1832824, NSF CAREER 2046468, ARL DEVCOM UWBG RF Electronics Center, and Lehigh Startup Funds.
[1] Dooley, J., Stoddard, N., Landskron, K. & Pimputkar, S. On the solubility of boron nitride in supercritical ammonia-sodium solutions. J. Cryst. Growth
621, 127381 (2023). doi: 10.1016/j.jcrysgro.2023.127381
Nanoconfined Lanthanum Hydride Nanoconfinement in Functionalized Carbon Hosts
Authors: Shivanna Mohana , Elmslie Timoth , Duwal Sakun , Spataru Catalin , Piontkowski Zak , Teprovich Joseph , Allendorf Mark D. , Sharma Peter , Stavila Vitalie 
Published: December 2024

Metal hydrides with a high hydrogen content have long been considered for materials-based hydrogen storage and but are now attracting attention as potential high-temperature superconductors.1 Recently, we showed that cryo-milling lanthanum improves hydrogen diffusion, yielding a higher hydrogen-to-metal ratio of lanthanum hydride up to LaH4.2 Another strategy for improving the thermodynamics and hydrogen desorption kinetics of metal hydrides is nanoconfinement within porous hosts.3,4 However, this has not previously been achieved for lanthanum hydride (LaHx) due to the difficulty of isolating nanoparticles of La or La-hydrides.
In this work we demonstrate that LaHx can be infiltrated into two porous carbons: nitrogen-doped CMK-3 (NCMK-3) and undoped CMK-3, both with average pore size 4-5 nm. Transmission electron microscopy (TEM) images reveal that LaHx species are distributed uniformly throughout these hosts in NCMK-3 and CMK-3 with rod and spherical morphologies, respectively. X-ray absorption spectroscopy (XAS) and X-ray photoelectron microscopy (XPS) were used to probe the coordination environment of the LaHx species and composition lanthanum and nitrogen. Sieverts measurements indicate that LaHx@NCMK-3 desorbs up to 0.7 wt % hydrogen, which is higher than the non-nitrogen functionalized CMK-3 (0.5 wt%H). Density Functional Theory (DFT) and ab initio molecular dynamics (AIMD) calculations predict that host-guest interaction energies are favorable for porous carbon with pyridinic, pyrolic, or pyridonic nitrogen defects on a graphene surface, consistent with experimental data. Moreover, high-pressure experiments were conducted to understand the tunability of hydrogen content in presence of ammonia borane as a hydrogen source. These revealed that the as-prepared materials underwent an increase in H:La ratio from 1.5 to 3.0 with pressure. Our results demonstrate that nitrogen-doped nanoporous carbons can confine lanthanum hydrides, favor higher H:La ratios, and could serve as a platform for developing superconducting materials at relatively low pressures (compared with diamond anvil cells) and temperatures.

-W. Guan, R. J. Helmley, V. Viswanathan Combining pressure and electrochemistry to synthesize superhydrides PNAS
2021, 118, e2110470118.

Duwal, V. Stavila, C. Spataru, M. Shivanna, P. Allen, T. Elmslie, T. C. Seagle, J. Jeffries, N. Velisavljevic, J. Smith, P. Chow, Y. Xiao, Y. Meng, M. Somayazulu, P. A. Sharma Enhancement of hydrogen absorption and hypervalent metal hydride formation in lanthanum using cryogenic ball milling Phys. Rev. Mater., 2024, submitted.

Stavila, S. Li, C. Dun, M. A. T. Marple, H. E. Mason, J. L. Snider, et al.
Angew. Chem. Int. Ed.
2021,
60, 25815-25824.

Schneemann, L. F. Wan, A. S. Lipton, Y.-S. Liu, J. L. Snider, A. A. Baker, et al. ACS Nano
2020,
14, 10294-10304.
Effects of Anion or Cation Structures on the Interaction of Ionic Liquid with Cu3(BTC)2 Metal-Organic Frameworks
Authors: Koseki Kaito , Zheng Yumeng , Kinoshita Kentaro 
Published: December 2024

Metal-organic frameworks (MOFs) are a class of porous materials with highly periodic nanopores and enormous specific surface area, which allow us to achieve gas adsorption and catalytic applications superior to those based on conventional porous materials [1]. However, the structural degradation due to moisture absorption and fragility in many MOFs led to challenges for practical application. We have found a solution to inhibit this moisture degradation by filling ionic liquid (IL) into the nanopores of MOF; the composite materials are referred to as IL@MOF. In addition, in IL@MOF, it was also clarified that the fragility was improved while keeping the crystal structure [2]. However, the reason is still unclear.
In this study, we focus on the interaction of IL with MOF and the effects of IL types on the crystal structure of MOF. IL@MOF samples were prepared by filling imidazolium-based [Cnmim][Tf2N] with different cation alkyl side chain lengths (n = 2, 4, 8) into single crystal HKUST-1 MOF (Cu3(BTC)2), which was synthesized by the solvothermal method [3]. Here, the sample was given a name according to the cation alkyl side chain length, i.e., Cu3(BTC)2 filled with [C2mim][Tf2N] is named C2@ Cu3(BTC)2. X-ray photoelectron spectroscopy (XPS) was used to analyze the binding energy (B.E.) of MOF frames, and X-ray diffraction (XRD) was used to measure the lattice spacing of MOF.
XPS spectra of C 1s, O 1s, Cu 2p3/2 for Cu3(BTC)2 and C4@Cu3(BTC)2 are presented in Figs. 1(a), (b), and (c). The XPS spectra were corrected so that the peaks corresponding to the C–C (285 eV) for both Cu3(BTC)2 and C4@Cu3(BTC)2, confirmed by peak separation, became the same, as shown in Fig. 1(a). It was found that the B.E. of Cu 2p3/2 and O 1s decreased with IL filling. The decrease in B.E. from B.E. of Cu3(BTC)2 was larger for shorter alkyl side chain lengths (Fig. 1(d)). This may be attributed to the coordination of the anions of the ILs to Cu, which effectively decreased the oxidation number of Cu. The decrease in the oxidation number of Cu is expected to reduce the Cu–O interactions and elongate the Cu–O bonds. This was verified by the result of XRD measurement shown in Fig. 1(e), indicating that the lattice spacing of the (222) plane of Cu3(BTC)2 increased after IL filling. The increase in the lattice spacing by IL filling is larger for shorter alkyl side chain lengths. These results suggest that IL filling elongates the Cu–O bonds in Cu3(BTC)2, and that the effect is more significant for shorter side chain lengths. We will discuss the IL species dependence of the MOF framework modulation including anions in detail in the presentation.
[1] YU, Jia, et al., Materials Horizons, 2017, 4.4: 557.
[2] S. G. Koh, et al., J. Phys. Chem. C 2022, 126, 6736
[3] L. Li, F. Sun, J. Jia, T. Borjigina, and G. Zhu, CrystEngComm, 2013, 15, 4094.

Figure 1
Enhancing Energy Solutions and Environmental Remediation: Piezocatalysis in Ferroelectric High-Entropy Oxides and 2D Materials
Authors: Wu Jyh-Ming 
Published: December 2024

Hydrogen is the most abundant element on Earth, and it is a safe and efficient source of energy. Through electrocatalysis and photocatalysis water molecules can be split into O and H2, which can then be used for fuel. This has been widely studied as a promising approach to reduce CO2 emissions and reliance on fossil fuels. A solar-assisted electrochemical process that generates H2 without toxic byproducts is being investigated. Solutions involving the remediation of water pollutants, water splitting, and clean energy alternatives have been widely investigated. However, most semiconducting photocatalysts are not very efficient when used in water-based solutions, because they have a low quantum yield. This talk will report how the piezocatalyts and flexocatalysts can proceed with electrochemical reactions for highly efficient wastewater treatment and hydrogen production. Considering the piezophototronic effect in the visible range, we combined a ferroelectric component with a high entropy oxide (HEO) compound, which can significantly enhance the charge transfer of the HEO's surface, enhancing the catalytic activity (Figure 1). Theoretical calculations revealed that a ferroelectric component could create an inner electric field at interfacial phase boundaries and effectively moderate free carriers, strengthening the charge separation in the ferroelectric HEO catalyst. When an external mechanical force was coupled with photoirradiation, the photoinduced charge separation coupled with piezoelectric polarization enhanced the charge transport in trapping sites. In this talk, I will provide an overview of High Entropy Oxide (HEO) ferroelectric catalysts, along with advancements in piezocatalysts within 2D materials and ferroelectric domains. The concepts presented will pave the way for designing next-generation piezo-photocatalysts.
References

Y. T. Lin, S. N. Lai, J. M. Wu*, Advanced Materials 32 (34), 2002875, 2020.

SC Chang, HY Chen, PH Chen, JT Lee, JM Wu*, Applied Catalysis B: Environmental 324, 122204, 2023.

Figure 1
High-Loading Intermetallic PtCo Nanoparticles Supported on S-Doped Carbon for Oxygen Reduction Reaction Catalysts
Authors: Yang Hyunwoo , Chang HyunWoo , Lee KwangHo , Yang HyunWoo , Cho EunAe 
Published: December 2024

Improving catalysts for the oxygen reduction reaction (ORR) is crucial for commercialization of proton exchange membrane fuel cells (PEMFCs) due to the sluggish kinetics of ORR at the cathode. Current ORR catalysts face challenges such as high costs associated with precious metals and poor durability. A common approach to improve catalyst activity is to alloy Pt with transition metals, such as cobalt and nickel, to control the d-band center. Instead of the disordered PtM, Pt intermetallic compounds show improved ORR intrinsic activity and enhanced stability. Also, doping carbon supports with heteroatoms such as nitrogen and sulfur is a feasible strategy to enhance the interaction between the metal nanoparticles of the catalyst and its support, which leads to improved performance and stability of the catalysts.
In this study, we synthesized high-loading intermetallic PtCo nanoparticles supported on sulfur-doped carbon. High metal loading catalysts have significant advantages for practical PEMFC applications as they accelerate mass transport, leading to a reduction in voltage loss, especially under high current densities. To synthesize high-loading intermetallic PtCo nanoparticles, uniform sulfur doping on commercial carbon support is introduced, since sulfur sites can anchor metal nanoparticles even during a harsh heat treatment process. The sulfur sites not only minimize sintering, but also improve the electrochemical performance. Using this approach, high-loading (52.5 wt%) sub-5 nm PtCo intermetallic compounds with a Pt-rich shell (PtCo@Pt/S-BP) were successfully synthesized. The morphology and characteristics of the PtCo nanoparticles were confirmed through various techniques, including XRD, TEM, ICP-OES, HAADF-STEM, EDS mapping, and XPS analysis. In the half-cell test, PtCo@Pt/S-BP exhibited over 5-fold enhancement in mass activity and 6-fold increase in specific activity compared to commercial Pt/C. Additionally, the performance of PtCo@Pt/S-BP was maintained even after 50,000 cycles due to thermodynamically stable structure of the intermetallic phase and Pt-rich shell. This synthesis strategy provides a promising pathway for practical application of Pt-based catalysts in future PEMFCs.