Materials Chemistry Frontiers最新文献

Modifications to the metal substrate used in alkanethiol self-assembled monolayer (SAM) formation impact the structural characteristics of the thin films and their macroscopic interfacial properties. In this study, evaporated gold surfaces underwent electrochemical modification, where a monolayer of silver was deposited through underpotential deposition (UPD). The effects of such a modification of the gold substrate on the structural and interfacial properties of n-alkanethiol and CF₃-terminated SAMs, wherein the latter bears an interfacial dipole at the CF₃–CH₂ transition, were explored. Structural analysis of the films revealed well-ordered monolayers on both gold and UPD Ag surfaces. Ellipsometric thickness assessment and X-ray photoelectron spectroscopy (XPS) of UPD Ag surfaces showed that the adsorbates formed densely packed monolayers that were ∼4 Å thicker than their counterparts on gold. These variations were attributed to the different binding geometries adopted by the sulfur atoms on the respective metals, which in turn dictates the tilt angles and the orientation of the terminal moiety. Polarization modulation infrared reflection−absorption spectroscopy (PM-IRRAS) revealed a shift in the orientation of the chain termini, likely due to differences in the mobility of underlying methylene units between substrates. Moreover, odd–even effects in the contact angle data of both polar and nonpolar liquids show changes in interfacial wettability further highlighting the impact of the subtle change to the substrate on the film structure.

Addressing the escalating demand for lightweight, highly conductive, thin, large-area, and mechanically flexible materials with high electromagnetic interference (EMI) shielding effectiveness, alongside superior electrical and mechanical properties crucial for advanced wireless electronics and next-generation telecommunications (6G), we introduce a novel Cu-deposited basalt fiber fabric (BFF) fabricated via electroless Cu deposition across varying temperatures (room temperature to 60 °C). This material exhibits exceptional EMI shielding performance, achieving 81.7 dB in the X-band (8.2–12.4 GHz) at a minimal thickness of approximately 7.69 μm. Furthermore, it demonstrates significantly high electrical conductivity, reaching a peak of 4.81 × 10⁵ S m⁻¹, coupled with a low density of 3.08 g cm⁻³, substantially lighter than bulk Cu (8.96 g cm⁻³). The Cu-deposited BFF also possesses excellent mechanical properties, with breaking forces of 665 N (weft) and 3343 N (warp) achieved at the optimized deposition temperature of 50 °C, and superior Joule heating efficiency, reaching temperatures up to 136 °C at an applied voltage of 1.0 V. Integrating lightweight, high strength, thermal stability (up to 950 °C), and electrical conductivity, the Cu-deposited BFF presents itself as a sustainable and high-performance EMI shielding material with significant potential for scalable industrial applications.

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is the most commonly used hole transport layer (HTL) material in perovskite solar cells (PSCs) due to its high visible light transmittance, excellent solution processability, and wettability suitable for top perovskite formation. The presence of surface defects in PEDOT:PSS films decreases the photoelectric conversion efficiency (PCE) and long-term stability of PSCs. These defects lead to the formation of pores in the growth of perovskite films on PEDOT:PSS, impeding the extraction and transfer of effective charges. Therefore, in this article, cesium chloride is doped into PEDOT:PSS to enhance its surface morphology, reduce surface roughness, improve the quality of sulfide thin films, promote charge transfer ability between interfaces, enhance conductivity, reduce non radiative recombination of the device, and improve the photovoltaic performance of the device. The open circuit voltage (V_OC) increased from 1.00 V to 1.02 V, the short-circuit current (J_SC) increased from 21.04 mA cm⁻² to 21.72 mA cm⁻², the fill factor (FF) increased from 77.90% to 82.04%, and the PCE of MAPbI_3−xCl_x PSCs increased from 16.39% to 18.18%. Specifically, when using cesium chloride-doped PEDOT:PSS as the HTL, the PCE of the Sn-Pb PSCs increased from 19.49% to 21.44%.

Colloidal particles can act as artificial atoms in the synthesis of colloidal molecules that resemble molecular structures, provided they mimic valence behavior and atomic bonding. Chemically or structurally distinct patches on their surfaces can offer valence-like behavior, enabling inter-patch bonding. In this study, we demonstrate that patchy micelles of diblock copolymers can mimic atomic valence configurations and bond formation. We first synthesized a series of diblock copolymers to form spherical micelles with varying corona-to-core ratios. Then, we induced patches in linear, triangular, tetrahedral, trigonal bipyramidal, and octahedral configurations, mimicking atomic valence shapes, by crosslinking the core and modifying the solvent. Additionally, we confirmed that the size of patchy micelles, particularly those with a tetrahedral configuration, could be controlled by adjusting the total molecular weight of copolymers while preserving the corona-to-core ratio. Furthermore, by utilizing bond formation through the merging of patches, we successfully constructed colloidal molecules using multi-patch and single-patch micelles.

Recently, the inadequacies of natural enzymes, such as high production cost, reduced stability, and strenuous preparation methods, have been addressed by fabricating artificial nanozymes with exceptional stability, availability, and low production cost. Herein, a rapid, cost-effective, facile, and one-pot microwave-assisted synthesis was used to fabricate hemin/graphene nanocomposites (GF) as a nanozyme with peroxidase mimetic activity. During the process, hemin acted as the iron source to synthesize iron oxide nanoparticles (∼50 nm) uniformly decorated on the surface of reduced graphene oxide (rGO). Compared with rGO alone, the fabricated GF demonstrated an augmented capability to catalyse the reaction of colourless pyrogallol (Py) to its deep yellow oxidized product in the presence of hydrogen peroxide (H₂O₂). The focused synthetic approach resulted in high catalytic efficiency of the fabricated nanozyme in decomposing hydrogen peroxide with a ratio of 2 : 1 (graphene : hemin). The formed nanozymes were superparamagnetic with a magnetic moment (M_s) of ∼10.8 emu g⁻¹. Additionally, the biocompatibility of the nanozyme was assessed on NIH3T3 skin fibroblast cells, where no cytotoxicity was witnessed, showing potential for the utility of the developed nanozyme for biomedical applications. This work implies an innovative approach to synthesizing enzyme-mimetic nanozymes using in situ microwave-assisted fabrication with applications in biomedicine, biocatalysis, and biosensing.

Intact and healthy dental pulp is crucial for maintaining the integrity of teeth. A variety of impairments such as infection and trauma cause irreversible pulp damage, which require removal of pulp tissue and conventional root canal filling. However, this type of treatment fails to restore vital pulp. It is still a clinical challenge to discover how to regenerate pulp and prolong the lifespan of teeth. Regenerating tissues similar to dental structures with normal functions is putatively the aim in the tooth regeneration field. Currently, researchers preliminarily achieve tooth regeneration by applying dental pulp stem cells (DPSCs) and stem cells from human exfoliated deciduous teeth (SHED). While stem cell transplantation for pulp regeneration shows promise, it faces critical challenges including complex manipulation, low cell survival rates, and storage difficulties. This study introduces a novel nanoparticle-based biomimetic system that overcomes these limitations by emulating stem cell functions. Under hypoxic conditions, SHED release concentrated pro-angiogenic factors, which were encapsulated into cell membrane-coated nanomicrospheres, creating bionic dental pulp stem cells. This innovative design enables sustained and controlled cytokine release while maintaining biocompatibility through the protective cell membrane coating. In hindlimb ischemia and pulp regeneration models, the bionic system demonstrated significantly enhanced retention (48.58% at day 7 versus minimal SHED retention), superior blood perfusion restoration (72% of normal levels), and dramatically increased vascular density (7.6-fold higher than controls). This cell-free nano-delivery platform provides a stable, immune-compatible alternative for functional tissue regeneration, addressing key limitations of conventional stem cell therapies while offering practical advantages for clinical translation in the challenging environment of narrow root canals.

Circularly polarized luminescent (CPL) materials are essential for advanced optoelectronics, especially wide-color-gamut OLED displays. Here, BINAP-based enantiomers were synthesized via one-step methylation, yielding deep blue emission (CIE_y < 0.08) with high thermal stability and antioxidative properties, thus addressing the challenges in designing blue-emitting CPL materials for efficient, stable, and commercializable applications.

Prussian blue analogs (PBAs), as redox-active metal–organic frameworks, offer great promise for hybrid supercapacitors but are hindered by low conductivity and limited cycling stability. In this work, we present a robust composite of nickel hexacyanoferrate (NiHCF) and carboxyl-functionalized multi-walled carbon nanotubes (CNTs), synthesized via a simple ultrasonication-driven coordination engineering method for K⁺-ion capacitor applications. The NiHCF/CNT composite, stabilised by coordination between the Ni²⁺/Fe³⁺ centers of NiHCF and the carboxylate groups on functionalized CNTs, achieves a high specific capacity of 223 C g⁻¹ at 1 A g⁻¹, significantly outperforming its pristine components. The composite exhibits exceptional electrochemical stability, with capacity increasing to ∼230% after 5000 cycles, attributed to the progressive activation of redox centers and improved electrolyte wettability. Density functional theory (DFT) calculations confirm enhanced electronic interactions and reduced bandgaps due to synergism between NiHCF and CNTs. The primary charge storage mechanism involves K⁺ ion (de)intercalation, as verified by ex situ P-XRD and EIS studies. A symmetric NiHCF/CNT//NiHCF/CNT supercapacitor device further demonstrates a high energy density of 18.07 Wh kg⁻¹ and a power density of 10 kW kg⁻¹, with 95.43% retention over 10 000 cycles. This study presents a rational design strategy focused on coordination bond formation between the metal centers of PBA and carboxyl groups on CNTs, which facilitates the effective compositization and enables enhanced charge storage capacity, exceptional cycling durability, and long-term performance in potassium-ion energy storage devices.

Single atoms of iron coordinated to nitrogen embedded in a carbon support (Fe–N–C) are the most active platinum group metal-free catalysts for the oxygen reduction reaction (ORR) in renewable energy devices. However, Fe–N–C catalysts, usually derived from Fe-doped zeolitic imidazole frameworks, suffer from limited activity due to restricted utilization of their active sites, which are buried deep inside the carbon matrix. Herein, we report a unique and facile design approach based on the interplay between the oxidation state of Fe in the precursor and modulation of synthetic parameters to regulate the particle size, surface area and Fe doping towards increased accessible ORR active sites. The synthesized Fe–N–C catalyst demonstrates remarkably high ORR activity in 0.1 M KOH with an onset and half-wave potential of 0.988 V and 0.903 V vs. RHE, respectively, excellent 4e⁻ selectivity and durability. Our work paves the way for a new discussion in understanding the role of fundamental parameters that affect the material's properties through a unique design strategy.

We report an investigation of a controlled radical release produced by iron oxide nanoparticles (IONPs) of ca. 25 nm covalently grafted through phosphonic groups with a thermosensitive alkoxyamine, (6-(4-(1-((di-tert-butylamino)oxy)ethyl)benzamido)hexyl)phosphonate, having a relatively low homolysis temperature (k_d = 6.4 × 10⁻⁴ s⁻¹ at 77 °C, E_a = 117.8 kJ mol⁻¹). Action of an alternating current magnetic field (AMF) or light irradiation at 808 nm produces a rapid heating of the nanoparticles’ surface, which induces the homolysis of the C–ON bond of alkoxyamines facilitating the efficient formation of free radicals. We demonstrated based on homolysis kinetics investigated by electron paramagnetic resonance (EPR) spectroscopy that light irradiation at 808 nm (2.6 W cm⁻²) enables efficient radical release from grafted nanoparticles at 44 °C (t_1/2 = 23.6 min), whereas the free molecules required 20 h to show the same release at this temperature. AMF exposure accelerates the homolysis of alkoxyamine-grafted nanoparticles (16 kA m⁻¹, 2.9 mg mL⁻¹) twofold compared to the free alkoxyamine at 77 °C (t_1/2 = 7.9 min vs. 18 min). These findings underscore the critical importance of localized nanoscale effects, demonstrating that the homolysis rate on the nanoparticle surface under external stimuli is significantly higher compared to that under external solution heating, with this enhancement being even more pronounced under light irradiation.