ACS Applied Nano Materials最新文献

ZnGa₂O₄:Cr³⁺ (ZGC) long-persistent luminescent (PersL) nanomaterial is a potential bioimaging contrast agent without autofluorescence. However, the existing synthetic methods such as the hydrothermal method, solid-state method, and sol–gel method are generally struggling to reconcile the contradiction between small particle size and high PersL intensity, which hinder the clinical application of ZGC. In this study, ZGC nanoparticles are prepared via an “MOFs-template-removal” method. Their hydrodynamic size distribution exhibits a peak at 160 nm. The PersL intensity reaches 5.7-fold that of its hydrothermal ZGC counterparts. Mechanisms of size control and PersL enhancement via the “MOFs-template-removal” method are thoroughly investigated using PXRD, XPS, PersL decay curves, UV–vis DRS, elemental analysis, etc. The results show that the nanoscale dimension of the MOF template, with its abundant internal pores, facilitates the formation of smaller ZGC particles. Furthermore, the copious shallow electron traps on the surface are vital for enhancing the PersL intensity of ZGC-mofs. The wide bandgap (4.88 eV) of ZGC-mofs allows for the efficient absorption of 254 nm ultraviolet light in aqueous environments, promoting the PersL emission. Additionally, the experimental results also suggest that this method holds potential for controlling the size of ZnX₂O₄-type (X = Al, In) metallic oxides, not only broadening its application scope but also inspiring the development of bioimaging materials.

Photoluminescence (PL) in monolayer (1L) MoS₂ is highly sensitive to surface chemistry and ambient exposure, which can introduce defect states that modify radiative and nonradiative pathways. Herein, we investigate the influence of long-term environmental aging (up to 1 year, ∼60% relative humidity, ∼24 °C) on the PL spectra of CVD-grown 1L MoS₂, focusing on the influence of morphology on the evolution of PL emission. While both 1L flakes and continuous films suffer from aging to different degrees, MoS₂ films show significantly higher PL reduction, broader exciton line widths, and an enhanced trion-to-exciton (A^–/A⁰) intensity ratio compared to MoS₂ flakes. This pronounced PL quenching arises from the higher grain boundary density in films, which acts as a reactive site for defect generation under ambient exposure. Complementary temporal photoresponse studies further validate this observation, revealing higher dark current and longer decay times in the aged films, consistent with increased sulfur vacancy (V_S) concentration and defect-assisted trapping. Interestingly, the aged 1L MoS₂ exhibit persistent photoconductivity and synaptic behavior, characterized by optically driven modulation of conductance and carrier relaxation. To reverse the aging-induced degradation, moderate-temperature air annealing (200–300 °C) was employed. Remarkably, the annealing leads to substantial PL recovery in both flakes and films. Spectral deconvolution reveals a narrowing and blue-shifting of the exciton emission peak, along with a reduction in the A^–/A⁰ ratio, indicating oxygen-mediated passivation of sulfur vacancies. Density functional theory further explains the trend, showing that sulfur vacancies introduce midgap states that enable nonradiative recombination, whereas oxygen incorporation suppresses these states and re-establishes radiative recombination pathways. Overall, our results connect morphology-dependent defect dynamics to macroscopic optical/electrical aging signatures and identify simple air annealing as a scalable route to heal vacancy-type defects in 1L MoS₂.

Iron-based Prussian blue analogues (Fe-PBAs) have garnered significant attention as cathode materials for sodium-ion batteries due to their high specific capacity (∼170 mAh g^–1), environmental compatibility, and cost effectiveness. However, their performance is hindered by substantial crystalline water and structural defects, which result in the insufficient electrochemical activity of Fe^LS(C). The low contribution of Fe^LS(C) to the overall capacity, compared to Fe^HS(N), results in diminished battery performance and rapid cycling degradation. This study presents an innovative synthesis strategy for low-defect, high-sodium-content nanoporous Prussian blue using an oxalic acid-assisted single-iron-source method. Subsequent heat treatment effectively removes crystalline water and introduces a controlled number of defects, further modulating the nanoporous architecture and activating the Fe^LS(C) capacity. The resulting thermally treated nanoporous material (PBA-HT) exhibits a high stable discharge capacity of 120.2 mAh g^–1, an initial Coulombic efficiency of 95.4%, and an outstanding cycling stability (70.3% capacity retention after 1000 cycles at 5 C). Density functional theory calculations reveal that heat treatment reduces the crystal field energy, thereby activating Fe^LS(C). In situ electrochemical impedance spectroscopy and galvanostatic intermittent titration technique analyses confirm a significant enhancement in diffusion kinetics, facilitated by the optimized nanoporous structure, following thermal treatment. Moreover, PBA-HT demonstrates stable operation at extreme temperatures (−20 and 50 °C), highlighting its practical potential and offering a synthesis strategy for high-performance nanoporous Prussian blue analogues.

Tamoxifen (TAM) is a front-line option for the treatment of estrogen receptor (ER)-positive breast cancers, but TAM resistance often presents a significant challenge. The mechanism underlying this resistance is complex, but it mainly involves metabolic differences and increased expression of drug-resistant proteins, such as hexokinase 2 (HK2). In this study, a dual targeting (ER and CD44 receptor) nano hybrid micelle system (HTT@3-BP-CL) was designed. It was composed of the hyaluronic acid ester of the TAM active metabolite 4-hydroxytamoxifen (4-OH-TAM) and d-α-tocopheryl polyethylene glycol succinate and was loaded with the HK2 inhibitor prodrug 3-bromopyruvate cholesteryl ester (3-BP-CL). We reasoned that the use of 4-OH-TAM would minimize inconsistent efficacy caused by individual metabolic differences and that the 3-BP released in the acidic tumor microenvironment would inhibit the production of ATP and NADPH. We found that HTT@3-BP-CL induces ferroptosis of MCF-7/TAM cells through a mechanism that involves inhibition of HK2 and downstream effects on oxidative stress via decreased reduced glutathione and glutathione peroxidase activity. Off-target effects were minimized through dual targeting and responsiveness of the esterified prodrugs to the acidic tumor microenvironment. HTT@3-BP-CL exhibits an efficient antitumor effect with low toxicity in TAM-resistant breast cancer models in vitro and in vivo. Our research provides a strategy for TAM-resistant breast cancer therapy.

The structural, electronic, and multifunctional properties of undoped and Ho/Ca codoped BiFeO₃ (BFO) nanoparticles were studied through aliovalent A-site substitution. Rietveld refinement confirmed phase-pure rhombohedral BFO at 600 °C, while Ho/Ca incorporation induced lattice contraction, compressive strain, and a rhombohedral to orthorhombic transition (R3c → Pnma). Co-doping of Ho/Ca reduced the particle size from 75 to 27 nm, introduced structural disorders, and increased the surface area, as verified by Electron microscopy, Raman spectroscopy, and BET. XPS analysis explicitly confirmed Ho³⁺/Ca²⁺ substitution, revealed Fe²⁺/Fe³⁺ coexistence, and also demonstrated a marked rise in oxygen vacancies. VBS and UV-visible analysis showed Fermi-level shifts and bandgap narrowing from 2.22 to 2.05 eV, which improved charge transport and visible-light absorption. Magnetic measurements revealed a nearly 6-fold enhancement in weak ferromagnetism from 0.109 to 0.609 emu g^–1, originating from reduced size, lattice strain, and vacancy-driven Dzyaloshinskii–Moriya interactions, while ESR spectra confirmed suppression of the cycloidal spin structure and maximized spin canting in sample Bi_1–2xHo_xCa_xFeO₃ at x = 0.05. Optical absorption evidenced defect-mediated transitions, and ferroelectric and leakage analyses identified Bi_1–2xHo_xCa_xFeO₃ at x = 0.05 as the optimal composition balancing polarization retention with leakage suppression. Photocatalytic degradation of RhB followed, with Bi_1–2xHo_xCa_xFeO₃ at x = 0.05 sample achieving a high-rate constant of 0.02501 min^–1 and 97% degradation efficiency in 90 min, outperforming many oxide-based photocatalysts. Radical-trapping experiments identified ·OH as the primary active species driving the reaction. Overall, Ho/Ca codoping in BFO provides a powerful pathway to engineer crystal symmetry, defect chemistry, and spin interactions in BFO, delivering simultaneous improvements in their properties like ferroelectric, magnetic, and photocatalytic performance. This article revealed A-site aliovalent substitution in BFO as a versatile strategy for designing next-generation multifunctional perovskite materials.

Conductive metal–organic frameworks (MOFs) have emerged as highly promising microwave absorbers, leveraging the advantage of their inherent and tunable electrical conductivity at the nanoscale. However, challenges still exist in constructing conductive MOF (c-MOF) powder materials that simultaneously possess high electron transport efficiency and excellent stability, and this issue has restricted the expansion of their applications in practical functional scenarios. To solve these issues, three M-TCNQ (M = Cu, Fe, Ni, TCNQ = tetracyanoquinone dimethane) complexes with precisely controlled nanoscale dimensions and distinct microstructures were synthesized through a one-pot hydrothermal reaction in this work. The pure Cu-TCNQ nanorods exhibited broadband microwave absorption performance, achieving an effective absorption width (EAB) of 5.3 GHz at a thickness of 2.5 mm. The minimum reflection loss (RL_min) of paraffin-based Cu-TCNQ can reach −48 dB at a thickness of 4.2 mm, and the EAB value is 5.4 GHz at 3.0 mm. Combining the density functional theory (DFT) analysis, the resistance loss between Cu–N bonds and the interfacial polarization loss of the Cu-TCNQ promotes electromagnetic loss, which is intrinsically linked to its unique nanoarchitecture that enhances charge confinement and interfacial effects. This work presents a semiconductive metal–organic complex for microwave attenuation, and more promising MAMs can be developed by utilizing a dielectric loss mechanism and designing innovative semiconductive complexes.

PVDF-based TENGs can achieve enhanced performance through strategic modifications of their bulk and surface properties. Compositing PVDF with different fillers and examining their effects on its triboelectric properties in the context of TENG remains an open area for investigation. In this study, Cobalt Aluminum Layered Double Hydroxide (CoAlLDH) was incorporated into PVDF to investigate its effect on the triboelectric performance of PVDF through synergistic modification of its structural and surface features. The filler concentration optimization of the PVDF–CoAlLDH (PVLD) composite was carried out and correlated with the electroactive (EA) phase modulations, changes in surface features, and dielectric properties of the composites. An increase in the surface coverage of PVDF films via a progressive transition from the bead-like morphology of pristine PVDF to a more continuous surface morphology in the composites was observed by SEM analysis. Moreover, an enhancement in the EA phase content of PVDF was also observed with the incorporation of CoAlLDH by evaluation of the XRD and FTIR of the composites. EIS studies of the films showed an increase in the dielectric constant of PVDF from ∼4 to a maximum of ∼21 with an increase in CoAlLDH loading, indicating that PVLD films retain more surface charges compared to PVDF. The effect of incorporating CoAlLDH through synergistic modification of surface and structural properties of PVDF on their triboelectric output was analyzed. The maximum peak-to-peak voltage of pristine PVDF (∼50 V) increased significantly to ∼330 V for PVDF loaded with 20% CoAlLDH (PVLD-20%). Similarly, the current output increased from ∼4.1 μA for pristine PVDF to ∼10.6 μA for PVLD-20%. These measurements were obtained under a contact–separation force of 10 N and a frequency of 10 Hz, using Nylon-6 as the tribopositive layer. Resistive impedance matching of the PVLD 20% shows that the maximum power attained for pristine PVDF film was ∼0.4 mW, and it increased up to ∼5.12 mW at an equivalent external load. Moreover, the practicality of the TENG was demonstrated by glowing 56 LEDs connected in series by foot-tapping the TENG.

This study presents a low-temperature, external catalyst-free method for synthesizing dense forests of vertically aligned carbon nanotubes (VA-CNTs) directly on basalt fabrics, aiming to enhance their effectiveness as structural reinforcements in polymer matrices while imparting additional functionalities, including electrochemical behavior for combined structural and energy storage applications. By systematically varying the processing temperature, the iron oxides inherently present in basalt fibers are found to be uniformly activated as in situ catalysts via hydrogen annealing at 460 °C, whereas plasma-enhanced chemical vapor deposition (PE-CVD) allows for the synthesis of VA-CNTs at temperatures as low as 510 °C. The optimized PE-CVD process at 460/510 °C yields dense, well-aligned VA-CNT arrays with structural quality superior to thermally grown CNTs, while the processing temperatures significantly below conventional CVD temperatures (>700 °C) mitigate the thermal degradation of the fiber tensile properties. Electrochemical characterization reveals enhanced capacitive behavior of CNT-modified basalt electrodes combined with a starch-based polymer electrolyte, offering promising prospects for developing sustainable energy storage devices from eco-friendly composite materials based on mineral fibers and biobased matrices.

Silicon (Si) has attracted much attention as a Li-storage anode material with high theoretical capacity but suffers from severe volume expansion, uncontrolled solid electrolyte interface (SEI) formation, and poor conductivity. Herein, we fabricate a Si-based composite where Si nanoparticles are encapsulated in rGO-modified 3D hierarchically macroporous/-mesoporous TiO₂ (Si/rGO@3DHP-TiO₂). TiO₂ not only can suppress Si volume expansion and induce the generation of a thin and stable SEI film to prolong electrode lifespan but also can maintain structural integrity. The hierarchical pores enable efficient electrolyte/Li⁺ diffusion, while reduced graphene oxide in the TiO₂ framework provides abundant conductive interfaces, enhancing electron transport. This Si/rGO@3DHP-TiO₂ anode achieves a high-rate performance of 741.6 mAh g^–1 at a high current density of 5 A g^–1, and its capacity remains at 645.7 mAh g^–1 over 1000 cycles at 2 A g^–1. Furthermore, the assembled Si/rGO@3DHP-TiO₂//active carbon Li-ion hybrid capacitors can attain a high Max. energy/power density of 152.1 Wh kg^–1/10191.1 W kg^–1, along with 91.2% capacitance retention over 10,000 cycles at 1 A g^–1. The full battery assembled with a LiFePO₄ cathode exhibits a capacity retention of 91% after 500 cycles at 1 C. This design strategy thus holds great promise for the rational construction of high-performance Si-based anodes, offering valuable insights for advancing next-generation Li-ion energy storage systems.

The photocatalytic hydrogen evolution reaction (HER) from renewable biomass resources has received considerable attention. However, the design of effective and visible-light-responsive photocatalysts continues to pose significant challenges, particularly due to limited surface reaction efficiency. A strategy is introduced to enhance the photocatalytic HER activity on CdS nanorods by constructing a surficial proton shuttle layer. Surface sulfur atoms are oxidized to form a [SO₄]/[SO₄–H] proton shuttle layer through plasma oxidation in air, followed by acid treatment. The resulting [SO₄–H]/CdS structure facilitates improved electron–hole separation and enhances proton transfer from the liquid phase to the surface, leading to a substantial increase in HER performance. The HER rate over [SO₄–H]/CdS is measured at 21.9 mmol g^–1·h^–1, which is approximately 100 times higher than that of pristine CdS under the same photocatalytic conditions in the presence of ethanol. This study demonstrates the effectiveness of the surficial proton shuttle layer in boosting HER activity and presents a practical method for improving the photocatalytic efficiency of metal sulfide-based systems.