Article
Chemistry, Physical
Xun Xu, Tingyu Liu, Qiuyue Li
Summary: The study investigates the relative stability and optimal positions of intrinsic defects and Cu defects in LiAlO2 crystal, showing that Cu-Li is most stable in O-rich conditions and energetically preferred under O-poor conditions, leading to the optimum OSL signal. Furthermore, other trapped-hole centers such as Cu-Li-V-Li and STH in the crystal also play a role and need to be considered for overall crystal performance.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Ceramics
Hiroki Motomura, Daiki Tamao, Kohta Nambu, Hiroshi Masuda, Hidehiro Yoshida
Summary: This study experimentally demonstrates the athermal effect of a flash event under a DC electric field on high-temperature plastic deformation in a fine-grained 3Y-TZP polycrystal, and attributes it to the reduction in activation energy.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2022)
Article
Physics, Condensed Matter
Jinsong Jiang, Tingyu Liu, Liying Yang, Wenqi Song
Summary: The formation energy of intrinsic point defects in Er2O3 crystals was investigated using density functional theory and thermodynamic calculation. The influence of vibrational entropy on formation energy should be considered at high temperatures. The most stable defect changes from oxygen vacancies to erbium vacancies as the Fermi level increases.
SOLID STATE COMMUNICATIONS
(2023)
Article
Chemistry, Inorganic & Nuclear
Pavel Karen
Summary: This study investigates the point defect equilibrium and its relationship with oxygen nonstoichiometry in (CeBaFe2O5.5)-Ba-III-O-III.
JOURNAL OF SOLID STATE CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Pavel Karen
Summary: In double-cell perovskites LnBaFe2O5+w, only lanthanoids Ln = Pr to Gd support wide equilibrium nonstoichiometry w from 0 to >0.5. Experimental data shows that NdBaFe2O5+w behaves closest to a pure undoped oxide at 1000 degrees C, while Sm and Gd demonstrate larger differences in defect equilibria. The temperature-dependent defect equilibria across this series are approximated by a formal Ln(3+) for Ba2+ donor-doping model.
JOURNAL OF SOLID STATE CHEMISTRY
(2021)
Article
Chemistry, Physical
Ying Zhou, Xin Li, Lili Xi, Jiong Yang
Summary: In this study, first-principles calculations were used to investigate the complex intrinsic defects of four ternary diamond-like ABX(2) compounds (A: Cu/Ag; B: In; X: Te/Se). The results indicate that Cu-based compounds tend to generate acceptor VA defects with p-type, while Ag-based compounds tend to form donor BA defects with n-type. These findings were analyzed using the newly introduced density of energy (DOE).
JOURNAL OF MATERIOMICS
(2021)
Article
Materials Science, Multidisciplinary
Xuemei Zhang, Michael Y. Toriyama, James P. Male, Zhenzhen Feng, Shuping Guo, Tiantian Jia, Zhuoyang Ti, G. Jeffrey Snyder, Yongsheng Zhang
Summary: Embedding isoelectronic and isostructural XTe (X = Ca, Sr, Ba) compounds in Na-doped PbTe can significantly enhance thermoelectric performance through interface engineering and phonon scattering. The formation energies of charged intrinsic and extrinsic defects are investigated in a PbTe/PbXTe/XTe pseudo-interface, with low energy defects playing a crucial role in increasing Na concentration at the solid solution interface. Understanding these lowest energy defects paves the way for designing promising thermoelectric materials with interface phases.
MATERIALS TODAY PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Mao-Hua Du, Jiaqiang Yan, Valentino R. Cooper, Markus Eisenbach
Summary: This study investigates the defect formation and dopant incorporation in MnBi(2)Te(4) and MnBi(4)Te(7) through systematic density functional theory calculations, revealing that internal heterostructure induces large-size-mismatched antisite defects and substitutional dopants. Te-rich growth conditions can reduce bulk free electron density, while Na doping is proposed as an effective way to pin the Fermi level for observing surface quantum transport. The findings suggest strategies for defect engineering and doping in MnBi(2)Te(4), MnBi(4)Te(7), and related magnetic topological insulators.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Nabeel Anwar, Robert M. Harker, Mark T. Storr, Marco Molinari, Chris-Kriton Skylaris
Summary: CeO2 (ceria) is a vital material in solid oxide fuel cells and catalysis, and its defect chemistry has been revised using DFT+U calculations. The ground state of an oxygen vacancy is associated with two neighbouring reduced cerium sites, while a cerium vacancy is the least favourable defect. Displacing an oxygen interstitial defect leads to the formation of a stable peroxide species. The energetic ordering of Schottky defects is affected by the size of the supercell, with S<111> being more favourable than S<110> for larger simulation cells.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Chemistry, Physical
Kirill Gets, Ravil K. Zhdanov, Yulia Yu Bozhko, Vladimir R. Belosludov
Summary: Based on experimentally obtained clathrate hydrates structures, new ice phases were predicted using molecular and lattice dynamics methods. CS-IV was found to be a stable ice phase under negative pressure.
JOURNAL OF PHYSICAL CHEMISTRY C
(2021)
Article
Physics, Nuclear
Wei Zhang, Wan-Li Lv, Ting-Ting Sun
Summary: The study investigates the temperature dependence of shell corrections in closed-shell nuclei using covariant density functional theory. It is found that delta E-shell exhibits non-monotonous behavior and delta F-shell and T delta S-shell can be approximated well using specific formulas. Similar temperature dependencies are observed in other closed-shell nuclei such as Sn-100 and Pb-208.
Article
Materials Science, Multidisciplinary
Lihong Han, Yuanyuan Zou, Jia Liu, Baonan Jia, Gang Liu, Xiaoguang Ma, Haizhi Song, Pengfei Lu
Summary: First-principles methods were used to study the impact of intrinsic point defects on the electronic and optical properties of Ho:BYF crystal. It was found that fluorine vacancies and interstitial defects have lower formation energy and are more stable in the crystal structure. The interaction between doping Ho atom and fluorine vacancies may lead to a luminescence at around 2 μm in the crystal.
Article
Materials Science, Ceramics
Haixi Pan, Liping Feng, Xiaodong Zhang, Yang Chen, Gangquan Li, Yewei Dou, Jiongjie He
Summary: This study investigates the formation of intrinsic point defects and their impact on charge carrier trapping in 2D monolayer BiOX using first-principles calculations. It reveals that under O-poor conditions, donor defects can spontaneously form and induce high n-type conductivity, while under richer O conditions, acceptor defects increase, with both types compensating each other. The research offers insights into the defect physics of atomic-scale 2D BiOX and provides guidance for their optoelectronics and photocatalysis applications.
CERAMICS INTERNATIONAL
(2021)
Article
Chemistry, Physical
Neeraj Mishra, Guy Makov
Summary: The energetic and electronic properties of intrinsic point defects in germanium sulfide (GeS) were investigated using first-principles methods. It was found that the Schottky dimer (SD) is the most stable neutral defect, and Ge vacancies are the most stable defects in both Ge-rich and Ge-poor environments. GeS exhibits nonstoichiometric properties. The introduction of point defects affects the electronic structure of GeS, and Ge vacancies induce p-type conductivity.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Physics, Fluids & Plasmas
L. Yang, B. D. Wirth
Summary: This study investigates the energetics of intrinsic point defects and hydrogen behavior in six stable ground state tungsten borides using first-principles density functional theory calculations. The results provide insights into the interaction between vacancies and the atomic ratio of boron to tungsten, as well as the anisotropic diffusion behavior of hydrogen in tungsten borides. The study also highlights the different energetics of hydrogen in different compositions of tungsten borides.
Article
Chemistry, Physical
Dordije Tripkovic, Jiayue Wang, Rainer Kungas, Mogens Bjerg Mogensen, Bilge Yildiz, Peter Vang Hendriksen
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Physical
Subhash Chandra, Younggyu Kim, Daniele Vivona, Iradwikanari Waluyo, Adrian Hunt, Christoph Schlueter, Jeong Beom Lee, Yang Shao-Horn, Bilge Yildiz
Summary: Minimizing interfacial impedances is crucial for the development of solid-state batteries. This study investigates the reactions at the cathode-electrolyte interface and explores the chemical compatibility between the perovskite Li-solid electrolyte and potential cathode materials. The results suggest that elemental mixing and increased structural ordering occur, reducing the interface charge transfer resistance and facilitating fast charge transfer kinetics.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
Article
Chemistry, Multidisciplinary
Weiwei Fan, Baoming Wang, Rui Gao, Georgios Dimitrakopoulos, Jiayue Wang, Xianghui Xiao, Lu Ma, Kai Wu, Bilge Yildiz, Ju Li
Summary: Nanoparticles decorated electrodes (NDEs) have various applications in fields such as fuel cells. This study demonstrates that by subjecting a mixed ionic-electronic conductor to anodic or cathodic current/voltage shocks outside its electrochemical stability window, metallic nanoparticles can be uniformly dispersed, leading to improved electrocatalytic performance under normal functional conditions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Materials Science, Multidisciplinary
Geraldine Anis, Moataz M. Attallah, Mostafa Youssef, Hanadi Salem
Summary: Research interest in multi-principal element high entropy alloys (HEAs) has increased since 2004. This study used the calculation of phase diagrams (CALPHAD) method to construct phase diagrams of four HEA systems. The focus was on the single face-centered cubic (fcc) solid solution phase and a thermodynamic analysis was carried out to understand its stabilization. The results showed that the stability of the single fcc solid solution phase depended on temperature and could be either enthalpy- or entropy-stabilized. Additionally, the study explored the impact of interstitial nonmetals on phase equilibria.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2022)
Article
Chemistry, Physical
Weiwei Fan, Zhichu Ren, Zhu Sun, Xiahui Yao, Bilge Yildiz, Ju Li
Summary: Thermal-shock technique enables the fast synthesis of electrode powders and electrolyte powders, reducing the fabrication time of solid oxide cells and facilitating the development of new ceramic powders in a high-throughput and economical manner.
ACS ENERGY LETTERS
(2022)
Article
Remote Sensing
Hamada Rizk, Hirozumi Yamaguchi, Moustafa Youssef, Teruo Higashino
Summary: This article presents LiPhi(++), a system that utilizes transportable laser range scanners to automatically label WiFi scans and build a fingerprint database for indoor localization. LiPhi(++) achieves the same performance as traditional fingerprinting techniques without the associated overhead. It improves upon the accuracy of crowdsourcing-based and fingerprinting-based systems by a significant margin when tested with data collected at a later time.
ACM TRANSACTIONS ON SPATIAL ALGORITHMS AND SYSTEMS
(2023)
Article
Multidisciplinary Sciences
Murat Onen, Nicolas Emond, Baoming Wang, Difei Zhang, Frances M. Ross, Ju Li, Bilge Yildiz, Jesus A. del Alamo
Summary: In this study, highly desirable silicon-compatible nanoscale protonic programmable resistors were developed, enabling efficient and fast proton shuttling and intercalation at room temperature under extreme electric fields. The devices exhibited symmetric, linear, and reversible modulation characteristics, surpassing the space-time-energy performance of biological synapses.
Review
Chemistry, Multidisciplinary
Mantao Huang, Miranda Schwacke, Murat Onen, Jesus del Alamo, Ju Li, Bilge Yildiz
Summary: Artificial neural networks based on crossbar arrays of analog programmable resistors offer a solution to the high energy consumption challenge in artificial intelligence applications. Electrochemical ionic synapses, as three-terminal devices, show promising potential as programmable resistors in these arrays due to their uniform and deterministic control of electronic conductivity with low energy consumption. This article presents the desired specifications of these resistors, provides an overview of the current progress of devices based on different ions and material systems, and discusses the challenges that need to be overcome to achieve desirable properties.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Physical
Hoda El-Gibally, Nageh K. Allam, Mostafa Youssef
Summary: This paper presents an implementation of a self-consistent algorithm that finds the correct value of the dopant's chemical potential corresponding to a specific doping concentration, and calculates the distribution of the dopant's charge states based on this chemical potential.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Jiayue Wang, Dmitri Kalaev, Jing Yang, Iradwikanari Waluyo, Adrian Hunt, Jerzy T. Sadowski, Harry L. Tuller, Bilge Yildiz
Summary: Exsolution is a recent advancement in fabricating oxide-supported metal nanoparticle catalysts. The kinetics of metal exsolution depends on the kinetics of oxygen release from the host oxide, in addition to the kinetics of metal cation diffusion. This study demonstrates that in the thin-film perovskite SrTi0.65Fe0.35O3 (STF) system, surface oxygen release governs the metal nanoparticle exsolution kinetics. Increasing the oxygen release rate in STF accelerates the Fe0 exsolution kinetics and increases the quantity of exsolved Fe0 over time.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Jing Yang, Mostafa Youssef, Bilge Yildiz
Summary: Quantifying the distribution of charged defects and ions near the oxide/liquid interface is crucial for understanding important electrochemical processes. A grand canonical approach is used to establish a unified treatment of charged defects on the solid side and ions on the water side. By applying this approach to a ZrO2/water interface system, the structure, defect chemistry, and dynamical behavior are analyzed under different conditions. The model predicts solubility and point of zero charge consistent with experimental values and reveals the effects of dopant elements on the corrosion process.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Energy & Fuels
Dragos Neagu, J. T. S. Irvine, Jiayue Wang, Bilge Yildiz, Alexander K. Opitz, Juergen Fleig, Yuhao Wang, Jiapeng Liu, Longyun Shen, Francesco Ciucci, Brian A. Rosen, Yongchun Xiao, Kui Xie, Guangming Yang, Zongping Shao, Yubo Zhang, Jakob Reinke, Travis A. Schmauss, Scott A. Barnett, Roelf Maring, Vasileios Kyriakou, Usman Mushtaq, Mihalis N. Tsampas, Youdong Kim, Ryan O'Hayre, Alfonso J. Carrillo, Thomas Ruh, Lorenz Lindenthal, Florian Schrenk, Christoph Rameshan, Evangelos I. Papaioannou, Kalliopi Kousi, Ian S. Metcalfe, Xiaoxiang Xu, Gang Liu
Summary: In the past decade, exsolution has become a powerful method for decorating oxide supports with dispersed nanoparticles for energy and catalytic applications. Exsolved nanoparticles have set new standards in terms of activity, durability, and functionality, due to their exceptional anchorage and ability to be produced, transformed, and applied in various ways. When combined with multifunctional supports like perovskite oxides, exsolution becomes a promising platform for advanced energy materials. This review discusses the current status of exsolution and explores future research directions for its application.
JOURNAL OF PHYSICS-ENERGY
(2023)
Article
Chemistry, Physical
Dongha Kim, Adrian Hunt, Iradwikanari Waluyo, Bilge Yildiz
Summary: The segregation and re-incorporation of dopants in perovskite oxides can be influenced by the defect reactions involving cation vacancies and oxygen holes under different potential. Anodic conditions can lead to the re-incorporation of surface dopants into the bulk of the material, improving the oxygen exchange kinetics of the perovskite oxide surface.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Multidisciplinary Sciences
Sanaz Koohfar, Masoud Ghasemi, Tyler Hafen, Georgios Dimitrakopoulos, Dongha Kim, Jenna Pike, Singaravelu Elangovan, Enrique D. Gomez, Bilge Yildiz
Summary: The instability of the surface chemistry in transition metal oxide perovskites is a major obstacle to the long-term durability of oxygen electrodes in solid oxide electrochemical cells. However, the use of cathodic potential can significantly enhance the stability and electrochemical activity in oxygen reduction reaction by inducing the formation of the Ruddlesden-Popper phase, exsolution of Co, and suppression of Sr segregation. These findings provide insights into the factors that maintain an active surface for oxygen reduction and highlight the potential of using cathodic polarization for achieving desirable chemistries.
NATURE COMMUNICATIONS
(2023)