Activity

  • Sahl Sweet posted an update 5 days, 14 hours ago

    We report on localized nonlinear lattice deformation and nanoscale structural rearrangement in methylammonium lead triiodide films triggered by the combined action of light and voltage. These effects, revealed by second harmonic piezoresponse force microscopy, are connected with organic cation motion, implicating localized cation migration as a key contributor to perovskite optoelectronic device instability under operating conditions.Obtaining fresh nonlinear optical (NLO) materials is an attractive and challenging topic for the development of laser techniques. Using benchmark AgGaQ2 (Q = S, Se) as the template, new KAg3Ga8Se14 is obtained by a solid-state reaction. Its structure can be built by the intergrowth of 2  1 AgGaSe2 and Ga2Se3-like slabs if the K site is occupied by Ag. Powdery KAg3Ga8Se14 demonstrates moderate phase-matchable NLO responses, and a LDT of ca. 2 × AgGaS2. DFT calculations reveal that both AgSe4 and GaSe4 tetrahedral motifs contribute a lot to the NLO performance. This work reveals a new class of promising infrared NLO materials, and the design strategy may apply to other systems.Gold nanoplates (AuNPTs) exhibit outstanding photothermal conversion efficiency (68.5%) and peroxidase-like activity. The combination of the very low H2O2 concentration (0.1 mM) and the low AuNPT dosage (50 μg mL-1) with 808 nm laser irradiation (1 W cm-2, 3 min) shows excellent synergistic antibacterial ability and healing of MRSA-infected wounds in vivo.Using photocatalysis to produce clean H2 energy has been considered as one of the ideal strategies to alleviate the energy crisis and environmental pollution. In this work, the density functional theory (DFT) calculation was used as a guide to determine the experimental scheme of surface modification of Cu2O with Cu3P. With Cu2O as the core and Cu3P as the shell, the precursor was constructed by electrostatic self-assembly at first. After secondary calcination, Cu97P3 was formed from the compact interface between Cu2O and Cu3P, thus the 3D hierarchical structure of Cu-O-P(Cu2O@Cu97P3@Cu3P) was successfully constructed. The generation of Cu97P3 significantly increases the photocatalytic H2 production of Cu2O@Cu97P3@Cu3P under visible light irradiation. The photocatalytic activity of the composite with optimal ratio increased about 17 times as much as that of pure Cu2O. The separation and transportation efficiency of its photogenerated charges has been significantly improved. The 3D hierarchical core-shell structure is not only beneficial to strengthen the interface contact between different semiconductors but also to improve the transferability of photogenerated electrons. Through a series of experimental results, the strategy has proved to be successful that Cu3P was introduced onto the surface of the Cu2O octahedron to change the adsorption free energy of H atoms, reduce the overpotential of hydrogen evolution, and increase the active sites of hydrogen production. At the same time, the isolated interfaces are integrated by calcination to obtain Cu97P3 bridged substances derived from the interfaces. The presence of Cu97P3 establishes a new fast channel for electron flow between semiconductors, significantly accelerates the transfer of electrons, and ultimately improves the performance of photocatalytic hydrogen evolution. This work provides new insights into the design and flexible synthesis of inexpensive copper-based nano-photocatalysts.In numerous nanopore sensing applications transient interruptions in ion current through single nanopores induced by capturing solute molecules are a source of information on how solutes interact with the nanopores. We show that the distribution of time spent by a single captured solute molecule in a nanopore is bimodal with the majority of capture events being too fast to be experimentally resolved. As a result, the exact mean durations of the event and inter-event interval are orders of magnitude shorter than their measured values. Moreover, the exact and measured mean durations have qualitatively different dependences on the molecule diffusivity. This leads to a formal contradiction with the thermodynamics of molecule partitioning between the bulk and the nanopore. Here we resolve this controversy. We also demonstrate that, surprisingly, the probability of finding a molecule in the nanopore, obtained from the ratio of the measured mean durations of the capture event and interevent interval, is essentially identical to the exact equilibrium thermodynamic probability.The development of non-precious metal electrocatalysts with high activity, good durability and low cost to replace precious metal electrocatalysts is highly demanded for oxygen evolution reaction (OER). However, the higher overpotential, less catalytic sites and lower catalytic rate of precious metal electrocatalysts affect their practical application, which needs to be optimized from the aspects of structural design (e.g., specific morphology/particle size, geometric/electronic structures). In this study, we reported a high topological tri-metal phosphide of CoP@FeNiP derived from the composite structure of ZIF-67 twined on a FeNi-LDH shelled with ultrathin carbon networks (ZIF-67/FeNi-LDH) grown on a nickel foam. In the synthesis process of FeNi-LDH, the addition of polyvinylpyrrolidone (PVP) promoted the self-assembly of the topological structure of FeNi-LDH and further nucleation of the topological structure of the ZIF-67 precursor on FeNi-LDH. Besides, CoP@FeNiP inherits the topological structure of ZIF-67/FeNi-LDH. The obtained CoP@FeNiP/NF shows superior OER performance with a low overpotential of ∼283 mV at 100 mA cm-2, a low Tafel slope of ∼31.8 mV dec-1 and a conservation rate of catalytic activity of ∼98% after 110 h of continuous electrolysis at 10 mA cm-2. The remarkable activity of CoP@FeNiP/NF can be attributed to its unique structural features, such as the hierarchical morphology, large surface area, ultrathin carbon networks and the feature of phosphide, all of which simultaneously promote the OER process. Selleckchem Caffeic Acid Phenethyl Ester The extraordinary catalytic activities and stability of CoP@FeNiP/NF are significant to meet the industrial requirements for bulk water electrocatalysis.Bismuth(iii)-catalyzed regioselective functionalization at the C-6 position of tetrahydroquinolines and the C-5 position of indolines has been demonstrated. For the first time, one pot symmetrical and unsymmetrical arylation of isatins with tetrahydroquinolines was accomplished giving a completely new product skeleton in good to excellent yields. Most importantly, this protocol leads to the formation of a highly strained quaternary carbon stereogenic center, which is a challenging task. Benzhydryl and 1-phenylethyl trichloroacetimidates have been used as the alkylating partners to functionalize the C-6 and C-5 positions of tetrahydroquinolines and indolines, respectively. The scope of the developed methodology has been extended for the synthesis of the bioactive CYP19-inhibitor and its analogue.The enantioselective synthesis of 2-amino-4H-chromenes via the cascade rhodium-catalysed conjugate addition/hetero Thorpe-Ziegler reaction is reported. Moderate to good yields (up to 98%) and high enantioselectivities (up to 92% ee) were obtained with a chiral diene-coordinated rhodium complex as the catalyst. This protocol remedies the methodological deficiency in the asymmetric synthesis of 4-aryl 2-amino-4H-chromenes.Accelerated development of new therapeutics in an increasingly competitive landscape requires the use of high throughput analytical platforms. In addition, the complexity of novel biotherapeutic formats (e.g. fusion proteins, protein-polymer conjugates, co-formulations, etc.) reinforces the need to improve the selectivity and resolution of conventional one-dimensional (1D) liquid chromatography (LC). Liquid chromatography-mass spectrometry (LC-MS)-based technologies such as native LC-MS for intact mass analysis or peptide mapping (also called bottom-up approach)-based multi-attribute methods (MAM) have already demonstrated their potential to complement the conventional analytical toolbox for monoclonal antibody (mAb) characterization. Two-dimensional liquid-chromatography (2D-LC-MS) methods have emerged in the last ten years as promising approaches to address the increasing analytical challenges faced with novel antibody formats. However, off-line sample preparation procedures are still required for conventional 1D and 2D-LC-MS methods for the in-depth variant characterization at the peptide level. Multi-dimensional LC-MS (mD-LC-MS) combine sample preparation and multi-level (i.e. intact, reduced, middle-up and peptide) analysis within the same chromatographic set-up. This review presents an overview of the benefits and limitations of mD-LC-MS approaches in comparison to conventional chromatographic methods (i.e. 1D-LC-UV methods at intact protein level and 1D-LC-MS methods at peptide level). The current analytical trends in antibody characterization by mD-LC-MS approaches, beyond the 2D-LC-MS workhorse, are also reviewed, and our vision on a more integrated multi-level mD-LC-MS characterization platform is shared.Through the first-principles density functional theory and the phonon Boltzmann transport equation, we investigated the phonon transport characteristics inside 1T-TiSe2. The calculation results of the lattice thermal conductivity (κl) show that the κl of TiSe2 is extremely low (1.28 W (m K)-1, 300 K) and decreases with the shrinkage of the sample size. Moreover, the results also prove the isotropic nature of thermal transport. By decomposing the contribution of the thermal conductivity according to the frequency, the κl of the single-layer TiSe2 is primarily attributed to the acoustic phonons and a small portion of optical phonons, with the frequency range of 0-4.5 THz. The calculation of the scattering rate further illustrates the competition of different scattering modes in this frequency range to verify the change in thermal conductivity of different sample sizes. The high scattering rate and low group velocity lead to the low thermal conductivity of the optical phonon mode in TiSe2. In addition, reducing the size of the system can significantly limit the thermal conductivity by eliminating the contribution of long mean free path phonons. When the characteristic length of the single-layer TiSe2 is about 14.92 nm, κl reduces to half. Our results also show that TiSe2 has an extremely high Grüneisen parameter (about 2.62). Further decomposition of the three-phonon scattering phase space and scattering rate demonstrates that in the range 0-4.5 THz, the absorption process is the main conversion form of phonons. We conclude that, due to the high Grüneisen parameter, the high anharmonicity in TiSe2 leads to the extremely low κl. This study provides κl related to the temperature, frequency, and MFP, and deeply discusses the phonon transport in TiSe2, which has great significance to further adjust the thermal conductivity to develop highly efficient thermoelectric materials and promote the application of devices based on TiSe2.Stimuli-responsive materials are able to undergo controllable changes in materials properties in response to external cues. Increasing efforts have been directed towards building materials that mimic the responsive nature of biological systems. Nevertheless, limitations remain surrounding the way these synthetic materials interact and respond to their environment. In particular, it is difficult to synthesize synthetic materials that respond with specificity to poorly differentiated (bio)chemical and weak physical stimuli. The emerging area of engineered living materials (ELMs) includes composites that combine living cells and synthetic materials. ELMs have yielded promising advances in the creation of stimuli-responsive materials that respond with diverse outputs in response to a broad array of biochemical and physical stimuli. This review describes advances made in the genetic engineering of the living component and the processing-property relationships of stimuli-responsive ELMs. Finally, the implementation of stimuli-responsive ELMs as environmental sensors, biomedical sensors, drug delivery vehicles, and soft robots is discussed.