Article
Chemistry, Physical
Mauricio Lopez Luna, Janis Timoshenko, David Kordus, Clara Rettenmaier, See Wee Chee, Adam S. Hoffman, Simon R. Bare, Shamil Shaikhutdinov, Beatriz Roldan Cuenya
Summary: The study investigates the structural and chemical evolution of oxide-supported iron nanoparticles during the activation stages and the CO2 hydrogenation reaction, revealing the preferential formation of iron surface oxides under reaction conditions. The results highlight the important role played by the oxide support in the final structure and composition of nanosized catalysts.
Article
Nanoscience & Nanotechnology
Deok-Yong Cho, Ki-jeong Kim, Kug-Seung Lee, Michael Lubben, Shaochuan Chen, Ilia Valov
Summary: Thin layers inserted between a metal electrode and a solid electrolyte can modify the transport of mass and charge at interfaces and affect electrode reactions. Incorporating C films in functional materials can alter the host's chemical properties and device functionalities. Using X-ray spectroscopies, it was found that inserting graphene or ultrathin amorphous C layers in a Ta2O5/Ta system can tune its chemical and electronic structures, thereby fundamentally changing the resistive switching functionalities.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Physical
Filipe C. Correia, Joana M. Ribeiro, Alexei Kuzmin, Inga Pudza, Aleksandr Kalinko, Edmund Welter, Adelio Mendes, Joana Rodrigues, Nabiha Ben Sedrine, Teresa Monteiro, Maria Rosario Correia, Carlos J. Tavares
Summary: Doped ZnO thin films with Ga3+ and Bi3+ ions exhibit distinct effects on the microstructure, with Ga3+ introducing static disorder and Bi3+ likely located at grain boundaries. Ga-doping results in compositional disorder, while Bi is not incorporated in the ZnO wurtzite cell but segregated to grain boundaries.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Yogesh Kumar, S. Tripathi, Mangla Nand, R. Jangir, V. Srihari, A. Das, R. Singh, U. Deshpande, S. N. Jha, A. Arya
Summary: This study investigated the effect of Nd doping on the structural, optical, and electronic properties of lanthanum monazite structure. Pure and Nd-doped LaPO4 powders were prepared and analyzed for their composition, oxidation states, crystal structure, and bandgaps. The results confirmed the successful substitution of Nd in the LaPO4 matrix and provided insights into the local structure using extended X-ray absorption fine structure analysis.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Multidisciplinary
Ziyi Chen, Andrew G. Walsh, Xiao Wei, Manzhou Zhu, Peng Zhang
Summary: This study investigates the electronic properties of Ag-25(SR)(18) and Au-25(SR)(18) and develops a unique method to analyze the charge transfer behavior of nanoclusters. Experimental X-ray spectroscopy is used to demonstrate the bonding properties of silver nanoclusters, with the staple motif shown to have a significant impact on their electronic properties. The effective X-ray analysis techniques developed here provide new opportunities for the site-specific study of other nanoclusters.
Review
Chemistry, Physical
Benjamin Rotonnelli, Marie-Sophie Dias Fernandes, Fabrice Bournel, Jean-Jacques Gallet, Benedikt Lassalle-Kaiser
Summary: Water electrolysis for hydrogen production provides a convenient and carbon-free option to regulate the intermittency of renewable energy sources. Efficient catalysts based on noble metals are currently used for large-scale production, but efforts are being made to reduce catalyst usage while maintaining their efficiency. Fundamental studies on catalyst structure, reaction intermediates, and failure modes support these efforts. Synchrotron-based techniques, such as X-ray photoelectron and X-ray absorption spectroscopies, can provide valuable information during the reaction. This article gives an overview of these techniques and their application to water electrolysis.
CURRENT OPINION IN ELECTROCHEMISTRY
(2023)
Article
Chemistry, Physical
Peter P. Murmu, Akhil Shettigar, Shen V. Chong, Zihang Liu, Dana Goodacre, Vedran Jovic, Takao Mori, Kevin E. Smith, John Kennedy
Summary: Oxygen vacancies have a significant impact on the phase separation and thermoelectric properties of ITO films, affecting factors such as electrical conductivity, Seebeck coefficient, optical transmission, and power factor. Tuning the stoichiometry of ITO films by adjusting oxygen partial pressure during deposition can lead to phase separation and improved optical transparency, but may result in a decrease in power factor.
JOURNAL OF MATERIOMICS
(2021)
Article
Chemistry, Multidisciplinary
Dong Young Kim, Geonhee Lee, Gil Yong Lee, Jungpil Kim, Kwangu Jeon, Keun Soo Kim
Summary: This study developed a flexible nanocomposite based on polydimethylsiloxane (PDMS), incorporating highly conductive carbon nanotubes and reduced graphene oxide, for high-performance wearable electrocardiogram (ECG) electrodes. The optimized nanocomposite demonstrated uniform surface characteristics and low contact resistance, making it a promising material for expanding the application scope of wearable electronic devices and personal health monitoring systems.
NANOSCALE ADVANCES
(2022)
Article
Physics, Applied
Juan-Jesus Velasco-Velez, Lorenz J. Falling, Denis Bernsmeier, Michael J. Sear, Pip C. J. Clark, Ting-Shan Chan, Eugen Stotz, Michael Haevecker, Ralph Kraehnert, Axel Knop-Gericke, Cheng-Hao Chuang, David E. Starr, Marco Favaro, Rik Mom
Summary: In situ x-ray spectroscopies are a powerful tool for studying the electronic structure of the electrode-electrolyte interface, but the design of spectro-electrochemical cells plays a crucial role in determining the measurements and processes that can be studied. It is important to choose the right cell design for the specific process of interest, and understanding the opportunities and limitations of different cell designs through case studies is essential for practical experiments.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Daniel Baranowski, Iulia Cojocariu, Alessandro Sala, Cristina Africh, Giovanni Comelli, Luca Schio, Massimo Tormen, Luca Floreano, Vitaliy Feyer, Claus M. Schneider
Summary: On-surface chemistry allows for the miniaturization of functional devices, with porphyrins being promising building blocks for exploring advanced nanoarchitecture. Covalently connecting molecular units can result in more stable molecular materials with improved charge transfer properties. The synthesis and properties of a covalent molecular network composed of interconnected constituents derived from halogenated nickel tetraphenylporphyrin on Au(111) are addressed in this study. The pi-extended two-dimensional material exhibits dispersive electronic features, while the functional Ni cores retain their single-active site character. The high robustness of transition metal cores provided by bottom-up constructed covalent nanomeshes opens up new possibilities.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
Miranda Martinez, Anil R. R. Chourasia
Summary: The Ti/SnO2 interface was investigated using x-ray photoelectron spectroscopy. Chemical interaction between SnO2 and the titanium overlayer at the interface resulted in the reduction of SnO2 to elemental tin and the oxidation of the titanium overlayer. The interface consisted of elemental Sn, SnO2, elemental titanium, TiO2, and Ti-suboxide. Thermal diffusion of the titanium overlayer was observed in the 200 degrees C samples, leading to complete oxidation of the titanium.
Article
Environmental Sciences
Gonzalo Bia, M. Gabriela Garcia, Nicolas J. Cosentino, Laura Borgnino
Summary: This study investigates the abundance, speciation, and dispersion of arsenic (As) in fresh volcanic ash from explosive Patagonian eruptions. Results show that the concentration, speciation, and mobility of As depend on the silica content of source magmas. Arsenic mainly accumulates on the surface of Al-silicate glass in volcanic ash. Atmospheric dispersion simulations reveal the impact of As-bearing ash on groundwater in Patagonia and surrounding areas.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Materials Science, Multidisciplinary
Yann Morizet, Valentin Jolivet, Nicolas Trcera, Tomo Suzuki-Muresan, Jonathan Hamon
Summary: The study investigated the possibility of dissolving iodine in borosilicate glasses using high-pressure synthesis, finding that I predominantly dissolves as iodide and using XPS and XAS methods to determine the speciation and surroundings of I. The results suggest that the borosilicate network is affected by the dissolution of I.
JOURNAL OF NUCLEAR MATERIALS
(2021)
Article
Materials Science, Ceramics
J. D. Eales, A. M. T. Bell, D. A. Cutforth, A. A. Kruger, P. A. Bingham
Summary: This study prepared three series of borosilicate glasses, including simple ternary sodium borosilicate glasses, complex borosilicate glasses, and high-level radioactive waste analogue glasses. The results showed that iron exists mainly as Fe3+ in predominantly distorted tetrahedral structures, and it integrates into the borosilicate network preferentially through either the silicate sub-network or the borate sub-network. The concentration of iron does not affect the boron coordination, indicating the presence of competing tetrahedral avoidance hierarchies.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2023)
Article
Chemistry, Physical
Arsene Chemin, Igal Levine, Marin Rusu, Remi Vaujour, Peter Knittel, Philipp Reinke, Karsten Hinrichs, Thomas Unold, Thomas Dittrich, Tristan Petit
Summary: This study elucidates the role of surface states on diamond materials for charge separation and emission under deep UV to visible light excitation. Four different spectroscopy methods were applied to diamond materials with different surface termination, doping, and crystallinity. Surface states were found to dominate sub-bandgap charge transfer, but the surface charge separation was drastically reduced in boron-doped diamond due to a high density of bulk defects. In a gaseous atmosphere, the oxidized diamond surface maintains a negative electron affinity, allowing charge emission. In an aqueous electrolyte, a photocurrent for illumination down to 3.5 eV was observed for boron-doped nanostructured diamond, independent of the surface termination. This study opens new perspectives on photo-induced interfacial charge transfer processes from metal-free semiconductors such as diamonds.
Article
Materials Science, Ceramics
Jin Young Oh, Dongwon Shin, Woo Seok Choi
Summary: This study uses data analytics and machine learning models to investigate the relationship between strain relaxation and physical and chemical features, and predicts the critical thickness. It provides insights for understanding the properties of thin films.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Physics, Multidisciplinary
Seung Gyo Jeong, Woo Seok Choi, Ahmed Yousef Mohamed, Deok-Yong Cho
Summary: Atomic-scale precision epitaxy of perovskite oxide superlattices provides a unique opportunity for controlling correlated electronic structures, activating effective control knobs for various functionalities. This study investigates the interplay between atomic and electronic structures of superlattices composed of correlated magnetic SrRuO3 and quantum paraelectric SrTiO3 layers. The results show that the customized octahedral distortion within the superlattices modifies the electronic structures of both Ti and Ru compounds, demonstrating the close correlation between atomic lattice and electronic structures enabled by atomic-scale epitaxy.
JOURNAL OF THE KOREAN PHYSICAL SOCIETY
(2023)
Article
Chemistry, Physical
Seung Gyo Jeong, Sehwan Song, Sungkyun Park, Valeria Lauter, Woo Seok Choi
Summary: This study presents a method of synthesizing spiral spin order through atomic-scale control, by achieving spiral spin structures in oxide superlattices composed of ferromagnetic metal and nonmagnetic insulator layers. This research contributes to the advancement of spintronic applications.
Article
Nanoscience & Nanotechnology
Deok-Yong Cho, Ki-jeong Kim, Kug-Seung Lee, Michael Lubben, Shaochuan Chen, Ilia Valov
Summary: Thin layers inserted between a metal electrode and a solid electrolyte can modify the transport of mass and charge at interfaces and affect electrode reactions. Incorporating C films in functional materials can alter the host's chemical properties and device functionalities. Using X-ray spectroscopies, it was found that inserting graphene or ultrathin amorphous C layers in a Ta2O5/Ta system can tune its chemical and electronic structures, thereby fundamentally changing the resistive switching functionalities.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Review
Chemistry, Multidisciplinary
Yoon Seok Oh, Lingfei Wang, Hyungwoo Lee, Woo Seok Choi, Tae Heon Kim
Summary: Growth and characterization of metal-oxide thin films have played a crucial role in the successful development of oxide-material-integrated thin-film devices. Functional oxide heterostructures have shown remarkable achievements in modern technologies and provided deeper insights into condensed-matter physics and materials science. The perturbations stemming from the ionic framework of an oxide, known as polar perturbations, have been extensively studied for their ability to advance functionalities and drive exotic physical phenomena in complex oxide heterostructures. The review provides a comprehensive summary of both intrinsic and extrinsic elements of polar perturbations and their potential for developing highly tunable functional properties.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Review
Chemistry, Multidisciplinary
Seung Gyo Jeong, Jin Young Oh, Lin Hao, Jian Liu, Woo Seok Choi
Summary: Unexpected and useful functionalities arise when different materials merge coherently. This review focuses on artificial oxide superlattices, specifically 4d and 5d perovskite oxide superlattices, which exhibit controllable correlated quantum phenomena due to their unique atomic and crystal structures. The review discusses various modulations and controls in crystal structures, electronic and magnetic properties, and integration of topology and correlation in these superlattices. It provides insights into the deliberate design of superlattice structures to achieve novel functionalities.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Dae-Sung Park, Aurora Diana Rata, Rasmus Tindal Dahm, Kanghyun Chu, Yulin Gan, Igor Maznichenko, Sergey Ostanin, Felix Trier, Hionsuck Baik, Woo Seok Choi, Chel-Jong Choi, Young Heon Kim, Gregory Jon Rees, Haflidi Petur Gislason, Pawel Adam Buczek, Ingrid Mertig, Mihai Adrian Ionescu, Arthur Ernst, Kathrin Doerr, Paul Muralt, Nini Pryds
Summary: Complex oxide heterointerfaces offer numerous physical properties and functionalities, leading to emerging technologies. Vertically aligned nanostructure (VAN) films, formed through a self-assembling bottom-up deposition method, show great promise in terms of structural flexibility and property tunability. This study introduces a new approach of bottom-up self-assembly using a mixture of 2D layer-by-layer film growth and 3D VAN film growth. The resulting two-phase nanocomposite thin films, based on LaAlO3:LaBO3, grown on a lattice-mismatched SrTiO3001 (001) single crystal, exhibit coexistence of multiple interfacial properties, including 2D electron gas and magnetic anisotropy. This approach offers multidimensional film heterostructures, enriching emergent phenomena for multifunctional applications.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Physical
Patrick M. Bacirhonde, Ahmed Yousef Mohamed, Byounggun Han, Deok-Yong Cho, Shrestha Devendra, Jong-Won Choi, Che-Ryong Lim, Emmanuel O. Afranie, Kyeong-Ho Baik, Kyoungin Kang, Sunny Lee, Eun-Suk Jeong, Nikhil Komalla, Nelson Y. Dzade, Chan Hee Park, Cheol Sang Kim
Summary: In this work, a binder-free Fe2-xRuxNb2O6 (FRNO) hybrid catalyst is designed for water splitting. The FRNO catalyst shows high electrocatalytic activity and stability in both acidic and alkaline media. Operando X-ray adsorption and density functional theory calculations reveal that the charge distribution of FRNO/CC is regulated, promoting water adsorption and dissociation and stabilizing *OOH adsorption on Ru and Fe, leading to improved oxygen evolution reaction (OER) performance.
ADVANCED ENERGY MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
In Hyeok Choi, Seung Gyo Jeong, Taewon Min, Jaekwang Lee, Woo Seok Choi, Jong Seok Lee
Summary: The electron-phonon coupling in synthetic crystals of SrRuO3 can be heavily modified by various intuitive tuning knobs, resulting in a 300-fold enhancement in quasi-2D SrRuO3 compared to bulk SrRuO3. This enhancement is due to the non-local nature of the electron-phonon coupling in the 2D electronic state. These findings offer valuable opportunities for engineering the electron-phonon coupling and advancing our understanding of strongly coupled charge and lattice dynamics in quantum materials.
Article
Materials Science, Multidisciplinary
Beom Yong Kim, In Soo Lee, Hyeon Woo Park, Yong Bin Lee, Suk Hyun Lee, Minsik Oh, Seung Kyu Ryoo, Seung Ryong Byun, Kyung Do Kim, Jae Hoon Lee, Deok-Yong Cho, Min Hyuk Park, Cheol Seong Hwang
Summary: This study systematically investigates the effects of TiN, Ru, and RuO2 top electrodes on the ferroelectric properties of Hf0.5Zr0.5O2 (HZO) films. The Ru top electrode significantly improves the ferroelectric performance, achieving a higher two-remanent polarization (2P(r)) value compared to TiN and RuO2 TEs. Interfacial engineering, such as inserting a HfON layer, further enhances the performance of the capacitor. This study highlights the importance of interfacial engineering in overcoming the trade-off between P-r and endurance in ferroelectric doped HfO2-based films.
ADVANCED MATERIALS TECHNOLOGIES
(2023)
Article
Chemistry, Multidisciplinary
Dongwon Shin, Hyeonbeom Kim, Sung Ju Hong, Sehwan Song, Yeongju Choi, Youngkuk Kim, Sungkyun Park, Dongseok Suh, Woo Seok Choi
Summary: Graphene and LaCoO3 hybrid heterostructure exhibits electrically tunable spin-exchange splitting, providing an opportunity for spin polarization control in spintronic devices.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Rahma Dhani Prasetiyawati, Seung Gyo Jeong, Chan-Koo Park, Sehwan Song, Sungkyun Park, Tuson Park, Woo Seok Choi
Summary: 4d transition metal perovskite oxides are used to study strongly correlated metallic properties. Among them, SrMoO3 (SMO) exhibits remarkable electrical conductivity at room temperature. The temperature-dependent resistivity (p(T)) shows Fermi-liquid behavior below the transition temperature T*, reflecting dominant electron-electron interaction. The T* can be modified significantly by-40 K in epitaxial thin films, with structural quality determining T*. The plasmonic properties are more directly governed by electron-impurity scattering, while the plasma frequency can be tuned by the change in electron-electron interaction.
CURRENT APPLIED PHYSICS
(2023)
Article
Nanoscience & Nanotechnology
Zhihao Yen, Teddy Salim, Chris Boothroyd, Peter Ferdinand Haywood, Cheng-Tai Kuo, Sang-Jun Lee, Jun-Sik Lee, Deok-Yong Cho, Yeng Ming Lam
Summary: This study demonstrates a new application of Cu-doped MILD-synthesized Ti3C2Tx MXene for urea removal. Cu doping increases the affinity of MXene for urea due to the formation of Cu-urea complexes. Cu-doped MXene follows monolayer adsorption on a homogeneous surface model.
ACS APPLIED NANO MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Ahmed Yousef Mohamed, Byoung Gun Han, Hyeonseo Jang, Jun Oh Jeon, Yejin Kim, Haeseong Jang, Min Gyu Kim, Kug-Seung Lee, Deok-Yong Cho
Summary: A Cu-deficient CuxInSe2 phase was successfully synthesized as a thin film using a two-step process. The study found that the loss of Cu in the compound resulted in changes in the chemical states and local structure of the Cu-Se-In tetrahedral networks, with a shorter In-Se bond and excessive oxidation of In ions. Furthermore, the narrowing of the bandgap was attributed to the reconstruction of the In3+ & delta; 5s orbital states, making the material suitable for photovoltaics.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
