NSF selects Sean Jones to head Mathematical and Physical Sciences directorate
The U.S. National Science Foundation has selected Sean Jones to serve as head of the Directorate for Mathematical and Physical Sciences. Jones has worked as an innovator in the field of materials science; an advocate for inspiring and training the next generation of researchers and skilled workers; and a leader at NSF, committed to institutional improvements that serve the science and engineering community as well as the public. He has served with NSF for more than a decade, starting ... More at https://www.nsf.gov/news/news_summ.jsp?cntn_id=301315&WT.mc_id=USNSF_51&WT.mc_ev=click This is an NSF News item. (Source: NSF News)
Source: NSF News - September 30, 2020 Category: Science Source Type: news
Stable perovskite solar cells with efficiency exceeding 24.8% and 0.3-V voltage loss
Further improvement and stabilization of perovskite solar cell (PSC) performance are essential to achieve the commercial viability of next-generation photovoltaics. Considering the benefits of fluorination to conjugated materials for energy levels, hydrophobicity, and noncovalent interactions, two fluorinated isomeric analogs of the well-known hole-transporting material (HTM) Spiro-OMeTAD are developed and used as HTMs in PSCs. The structure–property relationship induced by constitutional isomerism is investigated through experimental, atomistic, and theoretical analyses, and the fabricated PSCs feature high efficien...
Source: ScienceNOW - September 24, 2020 Category: Science Authors: Jeong, M., Choi, I. W., Go, E. M., Cho, Y., Kim, M., Lee, B., Jeong, S., Jo, Y., Choi, H. W., Lee, J., Bae, J.-H., Kwak, S. K., Kim, D. S., Yang, C. Tags: Chemistry, Materials Science reports Source Type: news
Center for Nanoscale Science renewed at $18 million for six years
(Penn State) The Center for Nanoscale Science, a National Science Foundation Materials Science and Engineering Center (MRSEC), has again successfully renewed its NSF support in the highly competitive MRSEC program. The new iteration of the center encompasses two of NSF's Big Ideas -- 'Quantum Leap' and 'Harnessing the Data Revolution.' (Source: EurekAlert! - Biology)
Source: EurekAlert! - Biology - September 21, 2020 Category: Biology Source Type: news
4 Balzan prizewinners announced today; professor Susan Trumbore wins For Earth System Dynamics
(Gold Communications) The names of the 2020 Balzan Prizewinners were disclosed today:Susan Trumbore (Germany/USA), Max Planck Institut f ü r Biogeochemie - Jena, for Earth System Dynamics,Jean-Marie Tarascon (France), Coll è ge de France - Paris, for Environmental Challenges: Materials Science for Renewable Energy,Joan Martinez Alier (Spain), Universitat Aut ò noma de Barcelona, for Environmental Challenges: Responses from the Social Sciences and the Humanities, Ant ô nio Augusto Can ç ado Trindade (Brasil), Universidade Federal de Minas Gerais - Belo Horizonte, for Human Rights. (Source: Eu...
Source: EurekAlert! - Social and Behavioral Science - September 14, 2020 Category: International Medicine & Public Health Source Type: news
Self-limiting directional nanoparticle bonding governed by reaction stoichiometry
Nanoparticle clusters with molecular-like configurations are an emerging class of colloidal materials. Particles decorated with attractive surface patches acting as analogs of functional groups are used to assemble colloidal molecules (CMs); however, high-yield generation of patchy nanoparticles remains a challenge. We show that for nanoparticles capped with complementary reactive polymers, a stoichiometric reaction leads to reorganization of the uniform ligand shell and self-limiting nanoparticle bonding, whereas electrostatic repulsion between colloidal bonds governs CM symmetry. This mechanism enables high-yield CM gene...
Source: ScienceNOW - September 10, 2020 Category: Science Authors: Yi, C., Liu, H., Zhang, S., Yang, Y., Zhang, Y., Lu, Z., Kumacheva, E., Nie, Z. Tags: Chemistry, Materials Science reports Source Type: news
Scale-free ferroelectricity induced by flat phonon bands in HfO2
Discovery of robust yet reversibly switchable electric dipoles at reduced dimensions is critical to the advancement of nanoelectronics devices. Energy bands flat in momentum space generate robust localized states that are activated independently of each other. We determined that flat bands exist and induce robust yet independently switchable dipoles that exhibit a distinct ferroelectricity in hafnium dioxide (HfO2). Flat polar phonon bands in HfO2 cause extreme localization of electric dipoles within its irreducible half-unit cell widths (~3 angstroms). Contrary to conventional ferroelectrics with spread dipoles, those int...
Source: ScienceNOW - September 10, 2020 Category: Science Authors: Lee, H.-J., Lee, M., Lee, K., Jo, J., Yang, H., Kim, Y., Chae, S. C., Waghmare, U., Lee, J. H. Tags: Materials Science, Physics reports Source Type: news
A key piece of the ferroelectric hafnia puzzle
Source: ScienceNOW - September 10, 2020 Category: Science Authors: Noheda, B., Iniguez, J. Tags: Materials Science perspective Source Type: news
How to imitate natural spring-loaded snapping movement without losing energy
(University of Massachusetts Amherst) Venus flytraps do it, trap-jaw ants do it, and now materials scientists at UMass Amherst can do it, too - they discovered a way of efficiently converting elastic energy in a spring to kinetic energy for high-acceleration, extreme velocity movements as nature does it. First author Xudong Liang and senior researcher Alfred Crosby have discovered at least one mechanism that works. (Source: EurekAlert! - Biology)
Source: EurekAlert! - Biology - September 3, 2020 Category: Biology Source Type: news
How dangerous are burning electric cars?
(Swiss Federal Laboratories for Materials Science and Technology (EMPA)) What happens if an electric car burns in a road tunnel or an underground car park? In the Hagerbach test tunnel in Switzerland, Empa researchers and tunnel safety expert Lars Derek Mellert set fire to battery cells of electric cars, analyzed the distribution of soot and smoke gases and the chemical residues in the extinguishing water. (Source: EurekAlert! - Medicine and Health)
Source: EurekAlert! - Medicine and Health - September 1, 2020 Category: International Medicine & Public Health Source Type: news
Low-cost, fly footpad-like adhesive structure capable of repeated attachment/detachment
(National Institute for Materials Science, Japan) NIMS, HUE and HUSM have succeeded in developing a method of easily and cheaply producing an adhesive structure capable of repeated attachment and detachment. The design of this structure was inspired by the adhesive spatula-shaped hairs (setae) found on the footpads of flies, while the method of producing it was hinted at by seta formation in fly pupae. These environmentally sound technologies could potentially contribute to a more sustainable society. (Source: EurekAlert! - Biology)
Source: EurekAlert! - Biology - August 28, 2020 Category: Biology Source Type: news
Accelerating water dissociation in bipolar membranes and for electrocatalysis
Catalyzing water dissociation (WD) into protons and hydroxide ions is important both for fabricating bipolar membranes (BPMs) that can couple different pH environments into a single electrochemical device and for accelerating electrocatalytic reactions that consume protons in neutral to alkaline media. We designed a BPM electrolyzer to quantitatively measure WD kinetics and show that, for metal nanoparticles, WD activity correlates with alkaline hydrogen evolution reaction activity. By combining metal-oxide WD catalysts that are efficient near the acidic proton-exchange layer with those efficient near the alkaline hydroxid...
Source: ScienceNOW - August 27, 2020 Category: Science Authors: Oener, S. Z., Foster, M. J., Boettcher, S. W. Tags: Chemistry, Materials Science reports Source Type: news
Super-durable ultralong carbon nanotubes
Fatigue resistance is a key property of the service lifetime of structural materials. Carbon nanotubes (CNTs) are one of the strongest materials ever discovered, but measuring their fatigue resistance is a challenge because of their size and the lack of effective measurement methods for such small samples. We developed a noncontact acoustic resonance test system for investigating the fatigue behavior of centimeter-long individual CNTs. We found that CNTs have excellent fatigue resistance, which is dependent on temperature, and that the time to fatigue fracture of CNTs is dominated by the time to creation of the first defec...
Source: ScienceNOW - August 27, 2020 Category: Science Authors: Bai, Y., Yue, H., Wang, J., Shen, B., Sun, S., Wang, S., Wang, H., Li, X., Xu, Z., Zhang, R., Wei, F. Tags: Materials Science reports Source Type: news
(University of California - Santa Barbara) When UC Santa Barbara materials scientist Omar Saleh and graduate student Ian Morgan sought to understand the mechanical behaviors of disordered proteins in the lab, they expected that after being stretched, one particular model protein would snap back instantaneously, like a rubber band. (Source: EurekAlert! - Biology)
Source: EurekAlert! - Biology - August 25, 2020 Category: Biology Source Type: news
Aerogel - the micro structural material of the future
(Swiss Federal Laboratories for Materials Science and Technology (EMPA)) Aerogel is an excellent thermal insulator. So far, however, it has mainly been used on a large scale, for example in environmental technology, in physical experiments or in industrial catalysis. Empa researchers have now succeeded in making aerogels accessible to microelectronics and precision engineering: An article in the latest issue of the scientific journal " Nature " shows how 3D-printed parts made of silica aerogels and silica composite materials can be manufactured with high precision. (Source: EurekAlert! - Biology)
Source: EurekAlert! - Biology - August 20, 2020 Category: Biology Source Type: news
Shaping colloidal bananas to reveal biaxial, splay-bend nematic, and smectic phases
Understanding the impact of curvature on the self-assembly of elongated microscopic building blocks, such as molecules and proteins, is key to engineering functional materials with predesigned structure. We develop model "banana-shaped" colloidal particles with tunable dimensions and curvature, whose structure and dynamics are accessible at the particle level. By heating initially straight rods made of SU-8 photoresist, we induce a controllable shape deformation that causes the rods to buckle into banana-shaped particles. We elucidate the phase behavior of differently curved colloidal bananas using confocal micro...
Source: ScienceNOW - August 20, 2020 Category: Science Authors: Fernandez-Rico, C., Chiappini, M., Yanagishima, T., de Sousa, H., Aarts, D. G. A. L., Dijkstra, M., Dullens, R. P. A. Tags: Materials Science, Physics r-articles Source Type: news
Covalent surface modifications and superconductivity of two-dimensional metal carbide MXenes
Versatile chemical transformations of surface functional groups in two-dimensional transition-metal carbides (MXenes) open up a previously unexplored design space for this broad class of functional materials. We introduce a general strategy to install and remove surface groups by performing substitution and elimination reactions in molten inorganic salts. Successful synthesis of MXenes with oxygen, imido, sulfur, chlorine, selenium, bromine, and tellurium surface terminations, as well as bare MXenes (no surface termination), was demonstrated. These MXenes show distinctive structural and electronic properties. For example, ...
Source: ScienceNOW - August 20, 2020 Category: Science Authors: Kamysbayev, V., Filatov, A. S., Hu, H., Rui, X., Lagunas, F., Wang, D., Klie, R. F., Talapin, D. V. Tags: Chemistry, Materials Science reports Source Type: news
Iron-based superelastic alloys with near-constant critical stress temperature dependence
Shape memory alloys recover their original shape after deformation, making them useful for a variety of specialized applications. Superelastic behavior begins at the critical stress, which tends to increase with increasing temperature for metal shape memory alloys. Temperature dependence is a common feature that often restricts the use of metal shape memory alloys in applications. We discovered an iron-based superelastic alloy system in which the critical stress can be optimized. Our Fe-Mn-Al-Cr-Ni alloys have a controllable temperature dependence that goes from positive to negative, depending on the chromium content. This...
Source: ScienceNOW - August 13, 2020 Category: Science Authors: Xia, J., Noguchi, Y., Xu, X., Odaira, T., Kimura, Y., Nagasako, M., Omori, T., Kainuma, R. Tags: Materials Science reports Source Type: news
Observation of small Fermi pockets protected by clean CuO2 sheets of a high-Tc superconductor
In cuprate superconductors with high critical transition temperature (Tc), light hole-doping to the parent compound, which is an antiferromagnetic Mott insulator, has been predicted to lead to the formation of small Fermi pockets. These pockets, however, have not been observed. Here, we investigate the electronic structure of the five-layered Ba2Ca4Cu5O10(F,O)2, which has inner copper oxide (CuO2) planes with extremely low disorder, and find small Fermi pockets centered at (/2, /2) of the Brillouin zone by angle-resolved photoemission spectroscopy and quantum oscillation measurements. The d-wave superconducting gap opens a...
Source: ScienceNOW - August 13, 2020 Category: Science Authors: Kunisada, S., Isono, S., Kohama, Y., Sakai, S., Bareille, C., Sakuragi, S., Noguchi, R., Kurokawa, K., Kuroda, K., Ishida, Y., Adachi, S., Sekine, R., Kim, T. K., Cacho, C., Shin, S., Tohyama, T., Tokiwa, K., Kondo, T. Tags: Materials Science, Physics reports Source Type: news
Chemical vapor deposition of layered two-dimensional MoSi2N4 materials
Identifying two-dimensional layered materials in the monolayer limit has led to discoveries of numerous new phenomena and unusual properties. We introduced elemental silicon during chemical vapor deposition growth of nonlayered molybdenum nitride to passivate its surface, which enabled the growth of centimeter-scale monolayer films of MoSi2N4. This monolayer was built up by septuple atomic layers of N-Si-N-Mo-N-Si-N, which can be viewed as a MoN2 layer sandwiched between two Si-N bilayers. This material exhibited semiconducting behavior (bandgap ~1.94 electron volts), high strength (~66 gigapascals), and excellent ambient ...
Source: ScienceNOW - August 6, 2020 Category: Science Authors: Hong, Y.-L., Liu, Z., Wang, L., Zhou, T., Ma, W., Xu, C., Feng, S., Chen, L., Chen, M.-L., Sun, D.-M., Chen, X.-Q., Cheng, H.-M., Ren, W. Tags: Materials Science, Physics reports Source Type: news
Sequencing of metals in multivariate metal-organic frameworks
We mapped the metal sequences within crystals of metal-oxide rods in multivariate metal-organic framework–74 containing mixed combinations of cobalt (Co), cadmium (Cd), lead (Pb), and manganese (Mn). Atom probe tomography of these crystals revealed the presence of heterogeneous spatial sequences of metal ions that we describe, depending on the metal and synthesis temperature used, as random (Co, Cd, 120°C), short duplicates (Co, Cd, 85°C), long duplicates (Co, Pb, 85°C), and insertions (Co, Mn, 85°C). Three crystals were examined for each sequence type, and the molar fraction of Co among all 12 sample...
Source: ScienceNOW - August 6, 2020 Category: Science Authors: Ji, Z., Li, T., Yaghi, O. M. Tags: Chemistry, Materials Science reports Source Type: news
Emergent helical texture of electric dipoles
Long-range ordering of magnetic dipoles in bulk materials gives rise to a broad range of magnetic structures, from simple collinear ferromagnets and antiferromagnets, to complex magnetic helicoidal textures stabilized by competing exchange interactions. In contrast, dipolar order in dielectric crystals is typically limited to parallel (ferroelectric) and antiparallel (antiferroelectric) collinear alignments of electric dipoles. Here, we report an observation of incommensurate helical ordering of electric dipoles by light hole doping of the quadruple perovskite BiMn7O12. In analogy with magnetism, the electric dipole helico...
Source: ScienceNOW - August 6, 2020 Category: Science Authors: Khalyavin, D. D., Johnson, R. D., Orlandi, F., Radaelli, P. G., Manuel, P., Belik, A. A. Tags: Materials Science, Physics reports Source Type: news
How hair deforms steel
Steels for sharp edges or tools typically have martensitic microstructures, high carbide contents, and various coatings to exhibit high hardness and wear resistance. Yet they become practically unusable upon cutting much softer materials such as human hair, cheese, or potatoes. Despite this being an everyday observation, the underlying physical micromechanisms are poorly understood because of the structural complexity of the interacting materials and the complex boundary conditions of their co-deformation. To unravel this complexity, we carried out interrupted tests and in situ electron microscopy cutting experiments with ...
Source: ScienceNOW - August 6, 2020 Category: Science Authors: Roscioli, G., Taheri-Mousavi, S. M., Tasan, C. C. Tags: Engineering, Materials Science reports Source Type: news
Exceptional plasticity in the bulk single-crystalline van der Waals semiconductor InSe
Inorganic semiconductors are vital for a number of critical applications but are almost universally brittle. Here, we report the superplastic deformability of indium selenide (InSe). Bulk single-crystalline InSe can be compressed by orders of magnitude and morphed into a Möbius strip or a simple origami at room temperature. The exceptional plasticity of this two-dimensional van der Waals inorganic semiconductor is attributed to the interlayer gliding and cross-layer dislocation slip that are mediated by the long-range In-Se Coulomb interaction across the van der Waals gap and soft intralayer In-Se bonding. We propose a c...
Source: ScienceNOW - July 30, 2020 Category: Science Authors: Wei, T.-R., Jin, M., Wang, Y., Chen, H., Gao, Z., Zhao, K., Qiu, P., Shan, Z., Jiang, J., Li, R., Chen, L., He, J., Shi, X. Tags: Materials Science reports Source Type: news
Cooperative carbon capture and steam regeneration with tetraamine-appended metal-organic frameworks
Natural gas has become the dominant source of electricity in the United States, and technologies capable of efficiently removing carbon dioxide (CO2) from the flue emissions of natural gas–fired power plants could reduce their carbon intensity. However, given the low partial pressure of CO2 in the flue stream, separation of CO2 is particularly challenging. Taking inspiration from the crystal structures of diamine-appended metal–organic frameworks exhibiting two-step cooperative CO2 adsorption, we report a family of robust tetraamine-functionalized frameworks that retain cooperativity, leading to the potential f...
Source: ScienceNOW - July 23, 2020 Category: Science Authors: Kim, E. J., Siegelman, R. L., Jiang, H. Z. H., Forse, A. C., Lee, J.-H., Martell, J. D., Milner, P. J., Falkowski, J. M., Neaton, J. B., Reimer, J. A., Weston, S. C., Long, J. R. Tags: Chemistry, Materials Science r-articles Source Type: news
Ultrahigh-strength and ductile superlattice alloys with nanoscale disordered interfaces
Alloys that have high strengths at high temperatures are crucial for a variety of important industries including aerospace. Alloys with ordered superlattice structures are attractive for this purpose but generally suffer from poor ductility and rapid grain coarsening. We discovered that nanoscale disordered interfaces can effectively overcome these problems. Interfacial disordering is driven by multielement cosegregation that creates a distinctive nanolayer between adjacent micrometer-scale superlattice grains. This nanolayer acts as a sustainable ductilizing source, which prevents brittle intergranular fractures by enhanc...
Source: ScienceNOW - July 23, 2020 Category: Science Authors: Yang, T., Zhao, Y. L., Li, W. P., Yu, C. Y., Luan, J. H., Lin, D. Y., Fan, L., Jiao, Z. B., Liu, W. H., Liu, X. J., Kai, J. J., Huang, J. C., Liu, C. T. Tags: Engineering, Materials Science reports Source Type: news
Anomalous absorption of electromagnetic waves by 2D transition metal carbonitride Ti3CNTx (MXene)
Lightweight, ultrathin, and flexible electromagnetic interference (EMI) shielding materials are needed to protect electronic circuits and portable telecommunication devices and to eliminate cross-talk between devices and device components. Here, we show that a two-dimensional (2D) transition metal carbonitride, Ti3CNTx MXene, with a moderate electrical conductivity, provides a higher shielding effectiveness compared with more conductive Ti3C2Tx or metal foils of the same thickness. This exceptional shielding performance of Ti3CNTx was achieved by thermal annealing and is attributed to an anomalously high absorption of elec...
Source: ScienceNOW - July 23, 2020 Category: Science Authors: Iqbal, A., Shahzad, F., Hantanasirisakul, K., Kim, M.-K., Kwon, J., Hong, J., Kim, H., Kim, D., Gogotsi, Y., Koo, C. M. Tags: Materials Science reports Source Type: news
Materials scientist James de Yoreo receives Distinguished Scientist Fellow award
(DOE/Pacific Northwest National Laboratory) The US Department of Energy's Office of Science bestows one of its highest honors on PNNL materials scientist James De Yoreo. (Source: EurekAlert! - Biology)
Source: EurekAlert! - Biology - July 22, 2020 Category: Biology Source Type: news