Nanotechnology最新文献

Memristors are promising candidates for artificial synapses in neuromorphic computing systems, yet their performance is often limited by nonlinear conductance modulation in oxide-based memristors. This work systematically investigates the modulation mechanism governing conductive filament (CF) rupture behavior utilizing distributed barrier layers based on finite element simulations. Our initial electro-thermal simulations of a HfO₂-based memristor with a single-layer Al₂O₃barrier (SLB) thickness (h= 0, 3, 6, 12 nm) showed only limited improvement in synaptic linearity. In contrast, the introduction of a (HfO₂/Al₂O₃)_nmultilayer barrier (MLB) structure fundamentally alters the switching dynamics. Simulations reveal that appropriately increasing the number of layers (n) promotes a transition from continuous to spatially discrete oxygen vacancy migration pathways. This engineered disorder expands the CF rupture region from a localized position to multiple interfaces, thereby reducing the electric field and temperature peaks and driving the set and reset process from abrupt to gradual switching. The optimized MLB device (n= 4) exhibits significantly enhanced synaptic linearity and analog switching characteristics, closely emulating biological synapse behavior. Furthermore, system-level validation using this device model achieved an accuracy of 94.34% in handwritten digit recognition. This work elucidates the physical mechanism by which MLBs enhance conductance linearity, providing a novel design strategy for high-performance memristive synapses.

Immunosuppression within the tumor microenvironment (TME) is a major factor driving pancreatic cancer progression and therapeutic resistance. To address this challenge, we developed a nano-codelivery system, CGT (Cilengitide)-Cls-PTX (paclitaxel)/CM (cell membrane), for the co-delivery of PTX and tumor cell lysate-derived antigens from pancreatic cancer cells (from human pancreatic cancer PANC-1 and mouse pancreatic cancer PANC02 cells). The system was constructed by synthesizing an integrinαvβ3-targeting lipid, DSPE-PEG₂₀₀₀-CGT, and fusing PTX-loaded liposomes with pancreatic cancer cell membranes. This strategy enables preferential accumulation in the TME, where tumor antigens are released to stimulate dendritic cell (DC) maturation and relieve TME immunosuppression, thereby achieving synergistic antitumor efficacy via PTX-mediated tumor cell killing and antigen-induced immune activation. Physicochemical characterization by¹H-nuclear magnetic resonance, transmission electron microscopy, and Western blot confirmed successful synthesis and membrane fusion. Immunostimulatory activity was evaluated using ELISA, flow cytometry, and co-culture assays, and therapeutic efficacy was assessed in a PANC02 murine pancreatic cancer model with Cls-PTX as the control. CGT-Cls-PTX/CM significantly enhanced DC maturation, upregulated co-stimulatory molecules (CD80, CD86), and promoted secretion of interleukin-6 (IL-6) and interleukin-12 (IL-12). Furthermore, it increased CD4⁺and CD8⁺T-cell proliferation, elevated interferon-γ(IFN-γ) production, suppressed transforming growth factor-β, and facilitated cytotoxic T lymphocyte infiltration into tumor tissues. Overall, CGT-Cls-PTX/CM effectively remodels the immunosuppressive TME, achieving synergistic antitumor effects through combined chemotherapy and immune modulation. This strategy offers a promising approach for enhancing immunotherapeutic efficacy against pancreatic ductal adenocarcinoma, a prototypical 'cold' tumor resistant to immune checkpoint therapy.

All-inorganic cesium lead halide perovskite quantum dots (PQDs), CsPbX3 (X=Cl, Br, I), exhibit exceptional potential in nonlinear optical (NLO) applications. This is due to their outstanding optoelectronic properties, including high photoluminescence quantum yield (PLQY), tunable band gaps, and strong absorption coefficients. However, their practical utility is severely limited by their environmental instability against ambient air and moisture. In this study, CsPbBr3 QDs were encapsulated in a SiO2 matrix using a sol-gel method to fabricate CsPbBr3/SiO2 gel-glass composites. Structural characterization(TEM, XRD, and FT-IR) confirmed the uniform dispersion and complete encapsulation of the QDs within the amorphous SiO2 network. Optical analyses revealed that the composites retained the intrinsic absorption and emission characteristics of the CsPbBr3 QDs (bandgap: 2.29 eV; fluorescence peak: 510 nm), while exhibiting tunable linear transmittance (50%-82%). Z-scan measurements under 532 nm picosecond pulsed laser excitation revealed significant nonlinear absorption coefficients (β) of up to 0.85 cm/GW and a low optical limiting threshold (OL) of 0.22 J/cm2. Importantly, SiO2 encapsulation markedly enhanced the environmental stability of the CsPbBr3 QDs, and their NLO properties remained stable after 365 days of storage under ambient air conditions. This work provides a viable strategy for realizing halide perovskite-based optical limiting devices and establishes a promising platform for further development. Future device-level integration and cycling tests will be essential for practical deployment.

An atomic switch (AS) device is a nanoionic switching device that operates through the electrochemical migration of metal ions and the subsequent formation or dissolution of metallic filaments within an electrolyte. Volatile AS devices are potential candidates as selector devices in cross-point array memory architecture. In this study, we improved the switching characteristics of an AS device by severely restricting Ag doping into the HfO₂electrolyte. Using a collimated sputtering process, we precisely controlled the amount of Ag doped in the electrolyte, and Ag doped AS device (W/HfO₂:Ag/Pt) exhibits a higher threshold voltage (V_th) and enhanced turn-off speed compared with conventional AS devices (Ag/HfO₂/Pt). To understand the origin of these improvements, we analyzed both Ag-doped AS device and a conventional AS device with the framework of field-induced nucleation theory. Both devices showed an exponential relationship between delay time and voltage, but with different values of nucleation barrier energies (W₀); the Ag-doped AS device exhibited a significantly higherW₀. These results indicate that limit restricting Ag doping increases the nucleation barrier energy, leading to less stable filaments and thereby improving switching characteristics.

As a prominent member of the Metal-Organic Frameworks (MOFs) family and a focal point in nanocarrier research, MIL-100(Fe) offers significant potential for enhancing derivative products through performance improvements achieved via optimized hydrothermal synthesis methods. This study addresses the selection of synthesis parameters-a topic long overlooked in hydrothermal methodologies-by systematically exploring the impact of various synthesis factors on the structure and performance of MIL-100(Fe). Single-factor experiments revealed that increasing the molar ratio of Fe3+ to BTC from 0.67 to 0.8 resulted in increases of over 60% and 170% in the specific surface area SBET and pore volume (Vp) of MIL-100(Fe), respectively. While maintaining other conditions constant, the effects of the Fe/HF ratio, Fe/HNO3 ratio, hydrothermal temperature, and activation temperature on the nanoparticle size, median diameter (D50), SBET, pore volume, and average pore diameter of MIL-100(Fe) were examined. The results indicate that MIL-100(Fe) exhibits optimal performance with a composition ratio of Fe:BTC:HF: HNO3 = 1:0.8:3:0.6, a hydrothermal reaction temperature of 175 °C, and an activation temperature of 160 °C.

Nanophotonic metamaterials exhibit application potential in micro/nano-optics owing to their unique optical properties. However, achieving dual-band perfect absorption with high quality factor remains a challenge. This study proposes a metamaterial featuring symmetry-broken silicon nanodisk arrays, which enables dual-band high-Q perfect absorption by transforming bound states in the continuum into quasi-bound states in the continuum and exciting an anapole mode. Numerical simulations demonstrate that the structure achieves absorption rates of 99.19% and 99.76% at wavelengths of 1068.55 nm and 1106.17 nm, respectively, with narrow linewidths of 1.08 nm and 0.84 nm, corresponding to Q-factors as high as 989 and 1316. Due to the polarization sensitivity of BIC, the absorption peaks can be switched on and off by adjusting the incident light polarization angle, offering a novel strategy for optical switching. Furthermore, as a dual-channel refractive index sensor, the metamaterial exhibits excellent sensing performance, with sensitivities of 81.9 nm RIU -1 and 139.5 nm RIU -1 , and figures of merit (FOM) of 75.83 RIU -1 and 166.1 RIU -1 . This work not only provides a new design route for ultra-high-Q dual-band perfect absorbers, but also offers technical support for cutting-edge applications such as dual-frequency channel sensor and photonic switching.

We report the first perovskite solar cell incorporating soybean lecithin, a biological plant-based food additive. When added in small concentration to perovskite precursor inks, it helps to obtain compact and uniform CsPbBr₃thin films. Our devices exhibit very high average visible transmittances (AVTs) (>70%), color rendering index (CRI) up to 84% and neutrality (CIE coordinates of 0.38, 0.39). The addition of lecithin almost doubled power conversion efficiency from 0.84% to 1.52%. Such high transparency, although limiting their overall efficiency, can be used in environments where transparency and color neutrality are important features, such as windows, facades, lens in smart glasses, and greenhouses. The transparency-efficiency profile fits the trend in performance of emerging photovoltaic devices, with amongst the highest voltages reported at these transmittances. Furthermore, the stability in ambient air also improved with addition of lecithin, losing only 25% of efficiency after 1 year versus 50% for devices with no lecithin.

This study investigates how liquid silicone rubber (LSR) content (5-20 vol.%) and graphene nano-platelets (GNP) loading (0-1 vol.%) affect the mechanical, thermal, and electrical properties of a dual epoxy/LSR matrix prepared by mechanical mixing. At 5 vol.% LSR and 0.2 vol.% GNP, the epoxy/LSR/GNP system shows a 25% toughness improvement compared with epoxy/GNP system. The system also demonstrates enhanced thermal stability over pure epoxy at 5 vol.% LSR and 1 vol.% GNP. Electrical bulk conductivity increases with higher LSR content (0-20 vol.%). A percolation threshold is reached at a very low GNP loading (0.8 vol%), yielding a marked conductivity rise. Overall, incorporating both LSR and GNP fillers into the epoxy matrix produces a composite with superior mechanical, thermal, and electrical properties, suitable for electrically conductive adhesives (ECAs).

A high-performance optical modulator based on three graphene layers integrated with a dual ellipticshaped silicon waveguide is proposed and investigated. The device is optimized for transverse electric (TE) mode operation, where the elliptic geometry is engineered to enhance modulation efficiency and compactness. The key performance indicators-including propagation loss (Lp), modulation depth (MD), bandwidth, energy consumption, and device footprint-are comprehensively analyzed through numerical simulations employing the finite element method (FEM). Simulation results reveal that the proposed modulator achieves a modulation depth of 0.748 dB/μm, a compact cross-sectional area of 1.08 μm², and a low propagation loss of 0.045 dB/μm at the telecommunication wavelength of 1550 nm. Further geometry optimization demonstrates enhanced modulation capability and reduced energy consumption. These results highlight the potential of the proposed structure as an energy-efficient and scalable candidate for future photonic integrated circuits (PICs) and for advancing active nanophotonic devices incorporating twodimensional (2D) materials.

Ferroelectric field-effect transistors (FeFETs), a type of ferroelectric memory with a transistor-based structure, have attracted significant attention from integrated circuit researchers due to their compact device architecture, non-destructive readout capability, and elimination of additional selector devices. These advantages make FeFETs highly promising for achieving higher storage density and enabling computing-in-memory applications. For their practical industrial deployment, extensive studies have been conducted on device fabrication, circuit design, and reliability. Among the key challenges, enlarging the memory window (MW) while maintaining stability is critical, as it directly affects data accuracy and retention. In this work, we experimentally investigate the modulation of the MW and interface defect density (ΔN_it) in Zr-doped HfO₂(HfZrO_x)-based FeFETs under different polarization states of the ferroelectric gate dielectric. The results demonstrate that with progressively enhanced ferroelectric polarization, the MW expands, while the interface trap density is simultaneously suppressed, suggesting that robust polarization effectively inhibits the formation of interface defects and improves subthreshold swing characteristics of the device. Furthermore, TCAD simulations were conducted to systematically investigate the impact of various ferroelectric properties, including remanent polarization (P_r), saturation polarization (P_s) and variations in coercive field (E_c), on the memory characteristics of HfZrO_xFeFETs. It was confirmed that higher polarization can alleviate the degradation caused by defects. In addition, an increase inP_randP_s, together with a lowerE_c, enhances the surface potential difference, charge separation, and switching efficiency, thereby improving both the MW and the stability of the device. This study provides valuable insights for the development of reliable FeFET-based memory technologies.