ACS Materials Letters最新文献

In this paper, Bi–Mo bimetallic oxides (Bi₂Mo₃O₁₂) were successfully grown on two-dimensional (2D) Ti₃C₂T_x MXene nanosheets by a hydrothermal reaction to form Bi₂Mo₃O₁₂@Ti₃C₂T_x composites and used for an electrocatalytic nitrogen reduction reaction. The experimental results show that in a 0.1 M Na₂SO₄ electrolyte the NH₃ yield rate of Bi₂Mo₃O₁₂@Ti₃C₂T_x reaches 78.52 μg^–1 mg^–1_cat. at −0.7 V vs RHE. This result is much higher than those of Bi₂Mo₃O₁₂ (23.45 μg h^–1 mg^–1_cat.) and Ti₃C₂T_x MXene (16.34 μg h^–1 mg^–1_cat.) alone. And the Faraday efficiency (FE) of Bi₂Mo₃O₁₂@Ti₃C₂T_x reaches the highest value of 49.38% at −0.55 V vs RHE (Bi₂Mo₃O₁₂, 12.16%; Ti₃C₂T_x MXene, 9.3%). Meanwhile, the ¹H NMR spectrum of ¹⁵N proves that the N of NH₃ in the experiment comes from the N₂ atmosphere passed during the experiment. Density functional theory (DFT) calculations indicate that the reduction pathway of N₂ on Bi₂Mo₃O₁₂@Ti₃C₂T_x is dominated by the distal pathway.

The donor–acceptor (D-A^•) radicals containing the tris(2,4,6-trichlorophenyl)methyl (TTM^•) acceptor have recently received much attention in view of their efficient luminescence. Since TTM^• is structurally alternant, based on the orbital-pairing features described for alternant hydrocarbons, it was proposed that the D-A^• molecule could exhibit emissive properties only when the donor component is nonalternant. This hypothesis seemed to be validated by the synthesis of the alternant TTM^•-tetracene system, which was measured to be nonemissive. While some experimental findings have deviated from the alternant rule, the underlying mechanism remains unclear. Here, we investigate quantum mechanically the excited-state properties of a series of TTM^•-acene radicals. The results of our high-level calculations highlight that alternant hydrocarbons should not be disregarded in the design of radical emitters, rationalize the absence of emission in TTM^•-tetracene, and lead to a set of simple rules to obtain highly luminescent TTM-D emitters.

Vasculature occupies a crucial position in maintaining human life. However, repairing vascular injuries remains an essential challenge in clinical treatment. In recent years, vascular tissue engineering has undergone rapid progress. Compared with traditional autogenous vessel grafting, artificial blood vessels have diverse advantages, benefiting from excellent biocompatibility, mechanical properties, and controllable structures. This review focuses on the recent development of artificial engineered blood vessels to offer a systematic review of fabrication and applications of this technique. Initially, preparation materials of artificial vessels are introduced. In addition, manufacturing methods of artificial vessels are discussed, including casting, spinning, 3D printing, and microfluidics. Then, the applications in vascular replacement therapy, vascular access for hemodialysis, and peripheral arterial disease are depicted. Finally, the recent challenges and prospects of this technique are described. It is hoped that this systematic review provides valuable information to relevant researchers and encourages advancements in the creation of tissue-engineered blood vessels.

We developed Salmonella typhimurium VNP20009 camouflaged biodegradable metal polyphenol nanoshells for efficiently reducing bacterial virulence and prolonging bacterial in vivo circulation time to increase bacterial tumor enrichment. The four-layer nanoshell-encapsulated VNP20009 (M₄@V) ensured the safety of treatment by effectively inhibiting bacterial proliferation and significantly reducing the toxicity in vivo. Moreover, the nanoshells significantly enhanced the biocompatibility of VNP20009 to protect it from phagocytosis, resulting in a 4-fold in vivo circulation time and a 1.97-fold increase in peak accumulation at the tumor sites. After the M₄@V colonized in the tumor microenvironment, physiologically relevant levels of ascorbic acid (AA) triggered the degradation of the nanoshells to restore the proliferation of VNP20009 at the tumor sites. Within 4T1 tumor-bearing mouse models, the AA+M4@V showed remarkable efficacy in suppressing both primary and metastatic tumors and was accompanied by a highly specific immune response.

Polycrystalline perovskite solar cells (PSCs) have achieved record efficiencies through facile passivation strategies during crystallization. By contrast, single-crystal PSCs face unique challenges. Their growth requires pristine, additive-free conditions, and controlling facet passivation remains difficult both during and after crystallization. These limitations primarily manifest as higher trap density at interfaces with charge-transport layers rather than within the crystal bulk. To address this challenge in single-crystal PSCs, we modified the hole-transport layer (HTL) surface by using a hydrophilic dielectric polymer. This treatment prevents charge leakage near pinholes while maintaining the single crystal adhesion. Our champion device achieved a high fill factor of 0.82, a large V_oc of 1.08 V, and a record-setting power-conversion efficiency of 25.0% for single-crystal PSCs. Furthermore, the polymer’s hydrophilic properties, combined with strong crystal adhesion, enhanced the device’s operational stability. This work advances single-crystal PSC technology by addressing critical interfacial engineering challenges through a strategic HTL surface modification.

Cellulose has gained significant attention as a sustainable resource due to its abundance, renewability, and biodegradability, making it a promising alternative to nonbiodegradable materials. Various cellulose-based materials (CBMs) have been engineered to improve the properties of natural cellulose. However, achieving full sustainability of CBMs remains challenging, primarily on account of the intensive pretreatment and fabrication processes involved. Therefore, this review highlights recent advances in balancing functionality and sustainability in CBMs. The first section examines the key parameters and mechanisms that influence the mechanical, thermal, barrier, and optical properties of CBMs, alongside their promising applications. Additionally, this review offers a comprehensive discussion on the sustainability of CBMs, focusing on (nano)cellulose extraction from renewable sources using green solvents, eco-friendly and scalable fabrication processes, and sustainable end-of-life strategies such as biodegradation and recycling. Overall, this review offers guidelines for designing functional and green CBMs, contributing to the broader goal of a circular, zero-waste society.

Ga-based liquid metal (LM) composites incorporated with nanofillers hold substantial promise for application in the micro/submicron scale thermal management of electronic devices. However, the uniform compounding of LM with carbon nanofibers (CNFs) without phase separation is challenging. Herein, ultrasonic dispersion and in situ surface modification (phenolic resin, PR) were conducted to obtain a eutectic Ga–In (EGaIn)/CNF@PR compound. To further improve the low out-of-plane thermal conductivity of EGaIn/CNF, 27 wt % diamond microparticles were compounded with EGaIn/CNF containing 0.027 wt % CNF. A high thermal conductivity of 100 W m^–1 K^–1 was obtained, which was 384% higher than that of EGaIn. Combining the interfacial adsorption energy analysis, the bonding microstructure in the composite was CNF(/diamond)@PR@(Ga,In)₂O₃/EGaIn. Additionally, the composite exhibited excellent thermal performance as a thermal interface material in practical CPU tests. This indicates that combined use of micro and nano fillers can remarkably augment LM’s thermal conductivity at a relatively low filler content.

The efficient harvesting of hot carriers (HCs) from high-energy photons can significantly enhance the optoelectronic performances. However, ultrafast HC cooling through intraband transitions poses a significant challenge for extraction using traditional semiconductor absorbers. The stable and compressible vacancy-ordered halide perovskites with isolated octahedra exhibit discrete electronic states at the conduction band edge, indicating the possible slow cooling of hot electrons (HEs). Using state-of-the-art ab initio quantum dynamics simulations and unsupervised machine learning (ML), we investigate the effect of lattice stress on HE dynamics in vacancy-ordered Cs₂SnBr₆. The moderate stress enhances structural rigidity and weakens dynamic electron–phonon interactions at the conduction bands. Such modifications and the widened energy gap at the conduction band edge partially suppress intraband nonadiabatic transitions, eventually elongating the HE lifetime. The pairwise mutual information extracts hard-to-find highly nonlinear dynamic structure-excited state property correlations, offering the unique opportunity to design efficient lead-free halide perovskites for HE-based optoelectronics strategically.

The characteristics of multiple ferroic orderings can afford potential applications such as mechanical switches, energy conversion, and pressure sensors. However, it remains a tremendous challenge to achieve multiple ferroic orderings due to rigorous requirements for certain symmetry in the crystal lattice and symmetry breaking. The organic–inorganic halide material has been regarded as possessing great potential for ferroelectric and ferroelastic phase transition for its unique structures. Herein, by modifying molecular symmetries, we successfully obtained the lead-free hybrid halide material (AMP)₂SbBr₅ (AMP = 2-Amino-2-methyl-1-propanol). With the help of hydroxyl insertion, the mirror symmetry was broken, realizing ferroelectric and ferroelastic phase transitions. The lone-pair electron activity as well as the directional ordering of the organic cations triggered the saturated polarization of 11.28 μC cm^–2, which is the largest polarization ever found in antimony-based molecular ferroelectrics. This study enhanced lead-free molecular ferroelectric development and offers instructive inspiration for designing multiple ferroic orderings.