Localized Surface Plasmon Resonance Meets Controlled/Living Radical Polymerization: An Adaptable Strategy for Broadband Light‐Regulated Macromolecular Synthesis

The photophysical process of localized surface plasmon resonance (LSPR) is, for the first time, exploited for broadband photon harvesting in photo‐regulated controlled/living radical polymerization. Efficient macromolecular synthesis was achieved under illumination with light wavelengths extending from the visible to the near‐infrared regions. Plasmonic Ag nanostructures were in situ generated on Ag₃PO₄ photocatalysts in a reversible addition‐fragmentation chain transfer (RAFT) system, thereby promoting polymerization of various monomers following a LSPR‐mediated electron transfer mechanism. Owing to the LSPR‐enhanced broadband photon harvesting, high monomer conversion (>99 %) was achieved under natural sunlight within 0.8 h. The deep penetration of NIR light enabled successful polymerization with reaction vessels screened by opaque barriers. Moreover, by trapping active oxygen species generated in the photocatalytic process, polymerization could be implemented without pre‐deoxygenation.     

Scalable Synthesis of Porous SiFe@C Composite with Excellent Lithium Storage

Utilizing cost-effective raw materials to prepare high-performance silicon-based anode materials for lithium-ion batteries (LIBs) is both challenging and attractive. Herein, a porous SiFe@C (pSiFe@C) composite derived from low-cost ferrosilicon is prepared via a scalable three-step procedure, including ball milling, partial etching, and carbon layer coating. The pSiFe@C material integrates the advantages of the mesoporous structure, the partially retained FeSi₂ conductive phase, and a uniform carbon layer (12–16 nm), which can substantially alleviate the huge volume expansion effect in the repeated lithium-ion insertion/extraction processes, effectively stabilizing the solid–electrolyte interphase (SEI) film and markedly enhancing the overall electronic conductivity of the material. Benefiting from the rational structure, the obtained pSiFe@C hybrid material delivers a reversible capacity of 1162.1 mAh g⁻¹ after 200 cycles at 500 mA g⁻¹, with a higher initial coulombic efficiency of 82.30 %. In addition, it shows large discharge capacities of 803.1 and 600.0 mAh g⁻¹ after 500 cycles at 2 and 4 A g⁻¹, respectively, manifesting an excellent electrochemical lithium storage. This work provides a good prospect for the commercial production of silicon-based anode materials for LIBs with a high lithium-storage capacity.     

Metathesis of P=C Bonds Catalyzed by N-Heterocyclic Carbenes

The catalytic metathesis of C=C bonds is a textbook reaction that has no parallel in the widely studied area of multiple bonds involving heavier p-block elements. A high-yielding P=C bond metathesis of phosphaalkenes (ArP=CPh₂, Ar=Mes, o-Tol, Ph) has been discovered that is catalyzed by N-heterocyclic carbenes (NHC=Me₂IMe, Me₂IⁱPr). The products are cyclic oligomers formally derived from ArP=PAr [i. e. cyclo-(ArP)_n; n=3, 4, 5, 6] and Ph₂C=CPh₂. Preliminary mechanistic studies of this remarkable transformation have established NHC=PAr (Ar=Mes, o-Tol, Ph) as key phosphinidene transfer agents. In addition, novel cyclic intermediates, such as, cyclo-(ArP)₂CPh₂ and cyclo-(ArP)₄CPh₂ have also been observed. This work represents a rare application of non-metal-based catalysts for transformations involving main-group elements.     

Cu3(HHTP)2 c-MOF/ZnO Ultrafast Ultraviolet Photodetector for Wearable Optoelectronics

Two-dimensional conductive metal–organic frameworks (2D c-MOFs) are a family of highly tunable and electrically conducting materials that can be utilized in optoelectronics. A major issue of 2D c-MOFs for photodetection is their poor charge separation and recombination dynamics upon illumination. This study demonstrates a Cu₃(HHTP)₂/ZnO type-II heterojunction ultraviolet (UV) photodetector fabricated by layer-by-layer (LbL) deposition, in which the charge separation of photogenerated carriers is enhanced. At optimized MOF layer cycles, the device achieves a responsivity of 78.2 A/W and detectivity of 3.8×10⁹ Jones at 1 V. Particularly, the device can be operated in the self-powered mode with an ultrafast response time of 70 μs, which is the record value for MOF-based photodetectors. In addition, even after 1000-time bending of 180°, the flexible device maintains stable performance. This flexible MOF-based UV photodetector with anti-fatigue and anti-bending properties provides strong implication to wearable optoelectronics.     

Bonding Character,Electron Delocalization,and Aromaticity of Cyclo[18]Carbon (C18) Precursors,C18-(CO)n (n=6, 4, and 2): Focusing on the Effect of Carbonyl (-CO) Groups**

The bonding character, electron delocalization, and aromaticity of the cyclo[18]carbon (C₁₈) precursors, C₁₈-(CO)_n (n=6, 4, and 2), have been studied by combining quantum chemical calculations and various electronic wavefunction analyses with different physical bases. It was found that C₁₈-(CO)_n (n=6, 4, and 2) molecules exhibit alternating long and short C−C bonds, and have out-of-plane and in-plane dual π systems (π^out and πⁱⁿ) perpendicular to each other, which are consistent with the relevant characteristics of C₁₈. However, the presence of carbonyl (-CO) groups significantly reduced the global electron conjugation of C₁₈-(CO)_n (n=6, 4, and 2) compared to C₁₈. Specifically, the -CO group largely breaks the extensive delocalization of πⁱⁿ system, and the π^out system is also affected by it but to a much lesser extent; as a consequence, C₁₈-(CO)_n (n=6, 4, and 2) with larger n shows weaker overall aromaticity. Mostly because of the decreased but still apparent π^out electron delocalization in the C₁₈-(CO)_n (n=6, 4, and 2), a notable diatropic induced ring current under the action of external magnetic field is observed, demonstrating the clear aromatic characteristic in the molecules. The correlation between C₁₈-(CO)_n (n=6, 4, and 2) and C₁₈ in terms of the gradual elimination of -CO from the precursors showed that the direct elimination of two CO molecules in C₁₈-(CO)_n (n=6, 4, and 2) has a synergistic mechanism, but it is kinetically infeasible under normal conditions due to the high energy barrier.     

A first-principles molecular dynamics approach for predicting optical phonon lifetimes and far-infrared reflectance of polar materials

The Lorentz oscillator model is well-known for its effectiveness to describe the far-infrared optical properties of polar materials. The oscillator strength and damping factor in this model are usually obtained by fitting to experimental data. In this work, a method based on first-principles simulations is developed to parameterize the Lorentz oscillator model without any fitting parameters. The high frequency dielectric constant is obtained from density functional perturbation theory, while the optical phonon frequencies and damping factors are calculated using an analysis of ab initio molecular dynamics trajectories. This method is then used to predict the far-infrared properties of GaAs, and the results are in good agreement with experimental data.     

Regularity of Global Attractor for Atmospheric Circulation Equations with Humidity Effect

Acta Mathematicae Applicatae Sinica, English Series - In this article, regularity of the global attractor for atmospheric circulation equations with humidity effect is considered. It is proved that...