Article
Materials Science, Multidisciplinary
Marco Turano, Marc Walker, Federico Grillo, Chiara Gattinoni, Gregory Hunt, Paul Kirkman, Neville V. Richardson, Christopher J. Baddeley, Giovanni Costantini
Summary: The study reveals that benzotriazole adsorbed on the copper surface changes its orientation with increasing molecular coverage, ultimately forming a self-limiting monolayer. CuBTA and Cu(BTA)2 metal-organic complexes are identified as the fundamental building blocks of this monolayer.
Article
Chemistry, Physical
Juan Carlos Martin Romano, Pablo Casado Aguilar, Amadeo L. Vazquez de Parga, Manuela Garnica, Oscar Rodriguez de la Fuente, Juan M. Rojo, Miguel Angel Nino
Summary: We report on the properties of thin films of L-dialanine and compare them to those of L-alanine on Cu(100) surfaces. The first dialanine monolayer consists of whole neutral molecules in a non-zwitterionic state, while the second and further layers are zwitterionic and readily desorb even at room temperature. The ordering of the dialanine overlayer is influenced by the rearrangements of the substrate atoms around dislocations.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Claudia Filoni, Klaus Wandelt, Lorenzo Marfori, Marco Leone, Lamberto Duo, Franco Ciccacci, Gianlorenzo Bussetti
Summary: Nowadays, the adsorption of sulfate on single Cu(111) crystals in diluted sulfuric acid solution is often used to test electrochemical scanning tunneling microscopy (EC-STM), which can detect a well-ordered sulfate superstructure and Moire patterns. However, when the applied potential is close to the anodic corrosion regime, instability during STM scanning can occur due to high faradaic currents and electrode surface disintegration resulting from copper dissolution. To overcome these difficulties, a combination of EC-STM and EC-atomic force microscopy (EC-AFM) is used to extend surface characterization to the corrosion regime and explore the effects of redox processes during cyclic voltammetry (CV).
APPLIED SURFACE SCIENCE
(2023)
Article
Chemistry, Physical
Bolin Wang, Zhao Jiang, Ting Wang, Qi Tang, Mingde Yu, Tao Feng, Min Tian, Renqin Chang, Yuxue Yue, Zhiyan Pan, Jia Zhao, Xiaonian Li
Summary: The study focuses on designing favorable structures for active sites to narrow the gap in activity between Cu-based and noble-metal-based catalytic systems for vinyl chloride production. A method for fabricating Cu single-atom catalysts is reported, with gradual release of C-Cl derivatives promoting vacancy-defect generation and significantly reducing the activity gap. Competitive adsorption between acetylene and hydrogen chloride on the CuCl2V-N site was found to enhance catalytic performance, and DFT calculations revealed a specific reaction mechanism catalyzed on the vacancy-defect CuCl2V-N site.
Article
Chemistry, Physical
Anastasiia I. Fadeeva, Vitaly A. Gorbunov, Pavel V. Stishenko, Sergey S. Akimenko, Alexander V. Myshlyavtsev
Summary: This theoretical work investigates the influence of randomly distributed point defects on the self-assembly and thermal stability of surface confined metal-organic networks (SMON). The study shows that an increase in surface concentration of point defects leads to a decrease in SMON melting temperature, with a maximum decrease of 15-23% relative to a homogeneous surface. Single-row structures melt through a first-order phase transition, while cloverleaf structures undergo a continuous phase transition due to weak hydrogen bonds and long-range interactions.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Physical
Soonho Kwon, Youn-Geun Kim, Jack H. Baricuatro, William A. Goddard
Summary: The systematic investigation of CO2 reduction on Cu(100) surfaces revealed a dramatic change in step-edge direction upon adsorption and desorption of CO at specific potentials, as observed by operando electrochemical scanning tunneling microscopy.
Article
Engineering, Environmental
Lele Zhao, Jiaming Zhang, Zhiping Zhang, Yujun Zhu, Yuan Zong, Chengying Bai, Tong Wei, Yueming Ren, Jun Ma
Summary: The effects of Cu oxidation states and reaction pH conditions on the properties of the copper-peroxy complex (---Cu-OOSO3-) and its catalytic degradation efficiency of bisphenol A were investigated. The results show that CuOx-30 with an average Cu valence of 1.61 exhibited the highest catalytic activity and electron-accepting ability. The reaction mechanism involved both single-electron transfer and oxygen-atom transfer pathways, which depended on the Cu oxidation states and reaction pH values.
JOURNAL OF HAZARDOUS MATERIALS
(2023)
Article
Chemistry, Physical
Reihaneh Amirbeigiarab, Olaf M. Magnussen
Summary: This study investigates the surface restructuring and adsorption layer properties of Ag-decorated Cu electrocatalysts. The results show that Ag-covered Cu electrodes undergo island restructuring and new island formation in carbonate solution, accompanied by a significant reduction in surface mobility. High-resolution imaging reveals a highly disordered molecular adsorption layer on the Ag-decorated Cu surface, contrasting with Ag-free Cu electrodes.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Reihaneh Amirbeigiarab, Olaf M. Magnussen
Summary: We present a study on AgCu electrodes using in situ scanning tunneling microscopy. The electrodes were prepared by electrodepositing submonolayer Ag on Cu(100) in 0.1 M H2SO4, resulting in monolayer islands with a hexagonal quasi-Ag(111) atomic lattice. Upon exchanging the solution to 0.1 M KHCO3, the Ag islands undergo restructuring, the nucleation and growth of new islands, and a reduction in surface mobility. Furthermore, disorder in the molecular adlayer is observed, suggesting that Ag redispersion on Cu electrocatalysts can occur even without CO2 reduction.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Mao Peng, Yunhao Wang, You Han, Chenliang Ye, Ji-Jun Zou, Wei Li, Jinli Zhang
Summary: This study used density functional theory (DFT) calculations to investigate the dissociation pathway of SiCl4 on CuCl2(100) surfaces, revealing that Cu-Si bonds and Cl defects can synergistically catalyze the conversion of SiCl4 into SiHCl3. The research provides insights into the rational design and synthesis of Cu-based catalysts for polysilicon production.
APPLIED SURFACE SCIENCE
(2021)
Article
Chemistry, Physical
Lei Xie, Jingyi Wang, Qiuyi Lu, Wenjihao Hu, Diling Yang, Chenyu Qiao, Xuwen Peng, Qiongyao Peng, Tao Wang, Wei Sun, Qi Liu, Hao Zhang, Hongbo Zeng
Summary: Minerals are crucial non-renewable resources essential in biological and technological applications. The surface interactions of mineral particles with other objects in aqueous suspensions play a critical role in mineral flotation. Nanomechanical tools such as SFA and AFM have advanced the quantitative measurement of interaction forces of minerals, leading to a better understanding of the surface interaction mechanisms at the nanoscale.
ADVANCES IN COLLOID AND INTERFACE SCIENCE
(2021)
Article
Chemistry, Multidisciplinary
Hao-Xin Liu, Zhiliang Gao, Han Yan, Shan-Qing Li, Wei-Wei Wang, Xuetao Qin, Hongning Sun, Jiwei Cui, Chun-Jiang Jia
Summary: Nanozymes are nanomaterials with natural enzyme-like characteristics, and they have shown great potential in various applications. reducible metal oxides with defect structures and single-atom catalysts with isolated metal sites are considered to be the most promising nanozymes. However, there are rarely reported strategies to construct highly efficient nanozymes by combining these advantages. In this study, we report the coordination-unsaturated single-atomic Cu species supported on sintered CeO2, which combines the benefits of defect engineering and single-atom catalysis, exhibiting significantly enhanced peroxidase-like activity.
SCIENCE CHINA-CHEMISTRY
(2023)
Article
Nanoscience & Nanotechnology
Zezhou Li, Justin Y. Cheng, Jonathan D. Poplawsky, Shuozhi Xu, Jon K. Baldwin, Irene J. Beyerlein, Nathan A. Mara
Summary: In this study, the local chemistry of three-dimensional (3D) interfaces in Cu/Nb nanocomposites was characterized using atom probe tomography (APT). The analysis revealed chemical heterogeneities along all spatial dimensions in the 3D interfaces, established the length scale and morphology of these features. It was found that the heterogeneities in 3D interfaces form through surface diffusion during physical vapor deposition (PVD), indicating that deposition parameters can be used to control interface structure and explore processing-structure-property relationships in interface-dominated nanocomposites.
SCRIPTA MATERIALIA
(2023)
Article
Chemistry, Applied
Jagannath Datta, Chiranjib Majumder
Summary: The study investigated the stability of metal atoms on a support and their impact on catalytic activity. It was found that defects in the support matrix could provide additional binding to enhance their stability, and through experiments and analysis, it was discovered that the stability of metal atoms at vacancy sites is higher.
Article
Materials Science, Multidisciplinary
Mohammad Sadeghi, Amir Zelati, Sahar Rezaee, Carlos Luna, Robert Saraiva Matos, Marcelo Amanajas Pires, Nilson S. Ferreira, Henrique Duarte da Fonseca Filho, Azin Ahmadpourian, Stefan Talu
Summary: In this study, Cu/Cr thin films were deposited on substrates of different nature using thermal evaporation. Non-contact AFM was applied to characterize the surface topography of the Cu/Cr samples. Various analyses were conducted to obtain important parameters and compare the surface morphology of different samples. The results demonstrated that all samples exhibited non-Gaussian randomly rough surfaces with the presence of multifractal features.
Editorial Material
Chemistry, Physical
Udo D. Schwarz
Summary: The processes of metallic asperities moving across each other at the atomic scale have been visualized, revealing unexpected behavior especially under tensile stress.
Article
Materials Science, Multidisciplinary
Evandro Martin Lanzoni, Omar Ramirez, Himanshu Phirke, Amala Elizabeth, Harry Moenig, Alex Redinger
Summary: Alkali post-deposition treatments (PDTs) have been shown to improve the power conversion efficiency of thin-film solar cells, with potassium effectively diffusing into the bulk of epitaxial CIGSe absorber layers. The diffusion of potassium depends on the Cu content of the absorbers, with Cu-depleted films showing higher diffusion rates for K. These treatments also increase PL yield, suggesting passivation of defects or increased doping.
Article
Materials Science, Multidisciplinary
Gregory S. Hutchings, Xin Shen, Chao Zhou, Petr Dementyev, Daniil Naberezhnyi, Inga Ennen, Andreas Huetten, Nassar Doudin, Jesse H. Hsu, Zachary S. Fishman, Udo D. Schwarz, Shu Hu, Eric Altman
Summary: In this paper, it is demonstrated that a single layer of 2D-VDW SiO2 can be grown by ALD on Au and Pd polycrystalline foils and epitaxial films. The choice of Si source in ALD can enable phase control, with ALD growth on Au producing predominantly the amorphous phase and SiO deposition in UHV leading to only the crystalline phase.
Article
Chemistry, Medicinal
Jaime Carracedo-Cosme, Carlos Romero-Muniz, Pablo Pou, Ruben Perez
Summary: This paper introduces the QUAM-AFM data set, the largest simulated AFM image data set to date, which is designed for chemical identification in organic chemistry. It includes 3D image stacks of 685,513 molecules, along with various data and a searchable graphical user interface.
JOURNAL OF CHEMICAL INFORMATION AND MODELING
(2022)
Article
Engineering, Mechanical
Wanfu Dong, Jianping Lai, Jiaxin Yu, Udo D. Schwarz, Yifan Zhang, Kun Zhu, Amit Datye
Summary: Understanding the structure-property relationship is essential for designing metallic glasses with advanced properties. In this study, nanoscratching experiments were conducted to establish a correlation between the structure and nano-tribological behavior of Zr-based metallic glasses. The results showed that the scratching depth and residual depth of the scratch track increased with an increase in the material's fictive temperature. Additionally, the effect of the fictive temperature on the friction coefficient varied with the applied load, with adhesion-induced friction dominating at low loads and plowing dominating at high loads. The study also revealed the occurrence of scratch-induced yielding and suggested the possibility of using ramping load scratching to characterize the ductile-to-brittle transition of metallic glasses as an alternative to time-consuming fracture tests.
Article
Nanoscience & Nanotechnology
Amala Elizabeth, Sudhir K. Sahoo, Himanshu Phirke, Tim Kodalle, Thomas D. Kuhne, Jean-Nicolas Audinot, Tom Wirtz, Alex Redinger, Christian A. Kaufmann, Hossein Mirhosseini, Harry Moenig
Summary: Alkali postdeposition treatments of Cu(In,Ga)Se-2 absorbers with KF, RbF, and CsF have been effective in improving the efficiency of chalcopyrite thin film solar cells. This study investigates the impact of RbF treatment on the electronic properties and defect physics of chalcopyrite absorber surfaces, showing that RbF treatment can effectively passivate electronic defect levels and prevent surface oxidation. X-ray photoelectron spectroscopy data reveals the presence of chemisorbed Rb on the surface, contributing to the surface passivation. Additionally, the diffusion of Rb along with other elements and the subsequent heat-induced formation of metallic Rb phases can lead to deterioration of the absorber-window interface.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Bertram Schulze Lammers, Nieves Lopez-Salas, Julya Stein Siena, Hossein Mirhosseini, Damla Yesilpinar, Julian Heske, Thomas D. Ku, Harald Fuchs, Markus Antonietti, Harry Moenig, Harry Moenig
Summary: In this study, the reacted layers of non-noble metal-organic compounds on a copper substrate were characterized using nc-AFM, XPS, and ab initio simulations. The dehydrogenation process and strong chemisorption of the molecular units on the copper substrate were observed. The interaction between nitrogen and copper atoms played a significant role in catalyzing the oxygen reduction reaction. The combination of atomic-scale characterization and electrochemical performance provided fundamental insights into the active sites of this technologically relevant reaction.
Article
Nanoscience & Nanotechnology
Ogulcan Acikgoz, Enrique Guerrero, Alper Yanilmaz, Omur E. Dagdeviren, Cem Celebi, David A. Strubbe, Mehmet Z. Baykara
Summary: In this study, atomic force microscopy was used to measure the friction on Re-doped MoS2. Unlike the common observation of decreasing friction with increasing number of layers in two-dimensional materials, Re-doped MoS2 exhibits friction that is inversely proportional to the number of layers. Raman spectroscopy measurements and ab initio calculations reveal that this phenomenon is related to Re intercalation, with an increase in out-of-plane stiffness inversely correlating with the number of layers as the physical mechanism behind this remarkable observation, revealing a distinctive regime of puckering for 2D materials.
Article
Chemistry, Medicinal
Lincan Fang, Xiaomi Guo, Milica Todorovic, Patrick Rinke, Xi Chen
Summary: Finding low-energy conformers of organic molecules on nanoclusters is a complex problem, which is further complicated by the constraints imposed by the presence of the cluster and other surrounding molecules. In this study, we modified our active learning molecular conformer search method to address this challenge, particularly focusing on avoiding steric clashes between the molecule and the cluster. Using a cysteine molecule on a gold-thiolate cluster as a model system, we demonstrated that the conformers in the cluster inherited the hydrogen bond types from isolated conformers but exhibited reordered energy rankings and spacings.
JOURNAL OF CHEMICAL INFORMATION AND MODELING
(2023)
Article
Materials Science, Multidisciplinary
Chiamaka Okafor, Amit Datye, Shuhan Zhang, Udo D. Schwarz, Yong Cai, Norman Munroe
Summary: This study successfully improved the mechanical and degradation properties of Mg-based bioresorbable stent materials by incorporating lithium. The enhancement was achieved through the reduction of secondary phases, formation of a lithium carbonate surface coating, and phase transformation.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Nanoscience & Nanotechnology
Jaime Carracedo-Cosme, Carlos Romero-Muniz, Pablo Pou, Ruben Perez
Summary: We propose a chemical characterization approach based on noncontact atomic force microscopy with metal tips functionalized with a CO molecule (HR-AFM) to resolve the internal structure of individual molecules. Our work demonstrates that a stack of constant-height HR-AFM images provides enough chemical information for the identification of quasiplanar organic molecules, and this information can be retrieved using machine learning techniques. The algorithm, trained with a large dataset, can generate the IUPAC name of the imaged molecule as the final output. Our findings highlight the potential of deep learning algorithms in the automatic identification of molecular compounds by AFM.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Physical
Milena Merkel, Amala Elizabeth, Marcus Boeckmann, Harry Moenig, Cornelia Denz, Nikos L. Doltsinis
Summary: The formation of surface relief gratings in thin azopolymeric films was studied. Molecular dynamics simulations were conducted and compared with experimental results. The simulations considered the photoisomerization dynamics and the orientation of the transition dipole moment, while the experiments used a spatial light modulator to illuminate the azopolymer film. It was observed that local heating and movement of molecules led to the formation of valleys, and the polarization of the incident light only had a small effect on the formation of grain-like structures in the valleys.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Emiliano Ventura-Macias, Carlos Romero-Muniz, Pablo Gonzalez-Sanchez, Pablo Pou, Ruben Perez
Summary: Functionalized tips with carbon monoxide (CO) in frequency modulation atomic force microscopy (AFM) can achieve high resolution imaging of molecules and reveal their internal structure on frequency shift maps. Traditionally, frequency shift measurements at low amplitudes have been interpreted as the force gradient between the probe and the sample, but our study shows that this interpretation fails for CO-terminated tips even at amplitudes as small as 0.2-0.3 Å. This is due to the rapid variation in tip-sample interaction caused by the mobility of the CO probe, which deflects to reduce the Pauli repulsion with the sample. In addition, we propose a new and simple approach to the frequency shift based on the force at the closest tip-sample separation, independent of CO deflection. This force approximation accurately reproduces the real frequency maps for amplitudes larger than ~0.3 Å.
APPLIED SURFACE SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Weiwei Jin, Amit Datye, Udo D. Schwarz, Mark D. Shattuck, Corey S. O'Hern
Summary: Experimental data on compressive strength versus strain rate for metallic glasses show varying sensitivity. Molecular dynamics simulations reveal that metallic glasses exhibit chevron-shaped scaling relation between compressive strength and temperature, with linear decrease at low strain rates and power law growth at high strain rates. The scaling behavior is affected by temperature and damping parameters, but can be explained within a general framework.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Damla Yesilpinar, Martin Vondracek, Patrik Cermak, Harry Monig, Jaromir Kopecek, Ondrej Caha, Karel Carva, Cestmir Drasar, Jan Honolka
Summary: We investigated the effect of low concentrations of iron on the physical properties of SnS van der Waals crystals grown from the melt. Through scanning tunneling microscopy (STM) and photoemission spectroscopy, we studied Fe-induced defects and observed an electron doping effect in the band structure of the native p-type SnS semiconductor. Our results showed that Fe preferentially occupies donor-like interstitial Fe-int sites in close proximity to V-Sn defects along the high-symmetry c-axis of SnS, leading to a reduction of p-type carrier concentrations.
