Materials Today Nano最新文献

Highly stretchable and mechanically foldable electronic devices such as photodetectors (PDs) have garnered significant attention in recent years. Nevertheless, existing devices in this category often compromise their photosensitivity and/or response time in order to achieve the desired stretchability. Here we present a novel free-standing stretchable photodetector constructed using electrospun ferroelectric P(VDF-TrFE) nanofibers (NFs) adorned with boron nitride quantum dots (BNQDs). The incorporation of BNQDs leads to a remarkable 160.0 % increase in the Young's modulus of the composite NFs and enhances their strain capacity to an impressive 120 %. Furthermore, it significantly augments the photoresponsivity by 847.8 %, primarily attributable to the abundant trap states present in the BNQDs. Additionally, we discovered a strong dependency of the giant photocurrent (I_ph) on the channel length (l), whereby I_ph ≈ 1/l². Notably, our fabricated devices exhibit exceptional stretchability, allowing for up to 100 % strain while maintaining a rapid rise time of approximately 15.6 ms and an expeditious decay time of 12.6 ms. Our findings underscore the significant potential of ferroelectric polymer NFs decorated with BNQDs in the realm of flexible optoelectronic applications.

Developing cost-effective acidic oxygen reduction reaction (ORR) catalysts with high performance is of great significance for proton exchange membrane fuel cells (PEMFCs) but very challenging. Transition-metal oxynitrides have high tolerance to harsh acidic media due to their excellent corrosion resistance, but they suffer from low acidic ORR activity. Here we report the discovery of a carbon-supported bimetallic niobium-iron oxynitride as a highly active and robust ORR catalyst in acidic media. This catalyst shows much higher ORR activity than its monometallic niobium oxynitride counterpart and exhibits a record high ORR activity among transition-metal oxynitrides, with an optimal ORR half-wave potential of 0.75 V vs. RHE, approaching those of atomically dispersed metal-N-C materials. It is revealed that the optimal catalyst has two types of Fe species with low oxidation state and two additional oxygen adsorption sites with high reactivity in comparison to its monometallic niobium oxynitride counterpart, therefore resulting in its remarkable ORR activity. Our work provides a new direction to explore efficient acidic ORR catalysts with low costs.

Under current technology trends, wearable devices with high levels of transparency and flexibility have become hotspots to improve aesthetics or enhance security for civilian and military applications. Simultaneously, the single sensor can no longer satisfy the various needs, like temperature and humidity, stress and strain and so on. However, it is still challenging that how to fabricate multifunctional transparent sensors nowadays. In this paper, the transparent polyurethane (PU) film was easily prepared by impregnating the ionic liquid (IL) into the pure PU film (PU@IL). And the effects of film thickness, ionic concentration and fiber morphology on transparency are investigated by experiments and simulations. On the basis of it, several sensors based on PU@IL film are further developed. The resistive sensor with PU@IL film shows different sensing abilities for stress, strain and temperature. Capacitive sensor based on indium tin oxide (ITO)-PU@IL-ITO has a lower stress detection limit (0.51 kPa) and faster response/recovery time (136.8 ms/68.4 ms). This paper may provide a novel strategy to design and fabricate multifunctional and multiform sensors with good mechanical properties, transparency and wide applications (preventing scalds, monitoring physiological activities).

To improve the photocatalytic activity of BiOF under simulated sunlight irradiation, a ternary Bi-based Z-scheme heterojunction of Bi/BiOF/Bi₂O₂CO₃ nanosheets were prepared using one-pot hydrothermal technique, where N, N-dimethylformamide was used as carbon source for Bi₂O₂CO₃ and reductant for metal Bi, bismuth nitrate was employed as Bi source and NaF was used as F source. The photocatalytic activity of Bi/BiOF/Bi₂O₂CO₃ was improved greatly towards ciprofloxacin degradation with the reaction kinetic constant of 0.0649 min⁻¹, which was 7 and 3.5 times to that of BiOF and Bi₂O₂CO₃, respectively. The improved photocatalytic activity was ascribed to the surface plasmon resonance effect of metal Bi and the synergistic effects of BiOF/Bi₂O₂CO₃ Z-scheme heterojunction, which facilitated the migration of the photogenerated electron and inhibited the recombination of photogenerated e⁻/h⁺ pairs. The degradation mechanism and charge transfer pathway were confirmed. This work expands the application of BiOF-based photoactive materials in environmental field.

The reduction of hazardous organic contaminants in agricultural wastewater to their corresponding amines is a key procedure in the fine chemical industry for pharmaceuticals, polymers, agrochemicals, and dyes. However, their effective and selective reduction reactions require compressed hydrogen at high temperatures, which are expensive and limited in supply. In this study, we present a novel approach using a layer-by-layer (LBL) assembly of copper metal–organic frameworks (MOFs) to prepare an earth-abundant, highly stable plasmonic nano-photocatalyst (i.e., Cu nanoparticles (NPs)) over Co₃O₄ nanocubes (indicated as CoO@Cu/C). The catalyst was produced by thermally treating the prepared core–shell material. Herein, highly monodispersed Cu NPs with an average size of 5 nm were embedded in the carbon shell on the surface of CoO. This unique composition resulted in a significant enhancement in the catalytic performance, yielding a remarkable efficiency (≈100 % after 60 s) and exceptional selectivity (≈98 %). Consequently, the reusable and sustainable CoO@Cu/C catalyst exhibited brings unattainable a remarkable catalytic performance and consistent activity even after six cycles in water owing to this unique composition of the homogeneously dispersed Cu-NPs inside the carbon shell. This, in turn, resulted in highly effective adsorption characteristics of the carbon matrix and high catalytic performance of ultra-small Cu-NPs on the CoO surface. Moreover, the activity of this catalyst is highly effective. This study presents an effective strategy for obtaining remarkable catalytic performance and selectivity via the coordination activation of Cu-NPs on the CoO surface.

Enhancing flow boiling in microchannel via surface modification is crucial for addressing the energy consumption challenges posed by high-power compact electronic devices. However, improving boiling heat transfer performance with well-defined nanostructured surfaces in a limited space remains a challenge. Herein, we present a simple and straightforward acoustofluidics strategy for stable, controllable, and efficient fabricates of functional Zinc oxide (ZnO) nanoarray silicon chip surface with excellent phase change cooling performance. The intentionally designed flower-like sharp-edge structure integrated acoustic has been experimentally and numerically verified for its enhanced mass transfer mixing. The resulting ZnO nanoarray-coated chip with customizable lengths, densities, and morphology is implemented by simple reactor parameter adjustment. Excellent boiling heat transfer performance is obtained on this surface, giving priority to nucleation (superheat≈ 4 °C), low energy consumption (≤3.2 kPa) and simultaneously enhancing the critical heat flux (CHF) and heat-transfer coefficient (HTC) by up to 70.8 % and 107.5 %, respectively, compared with a smooth chip surface. In situ observation and analysis of the wicking of the nanoarray and nucleation, growth, and departure of the bubbles reflect that ZnO nanoarray promotes the phase change heat exchange process by the large number of nucleation sites and ultrafast liquid re-wetting. These findings not only provide important guidelines for the precise control and rational design of functional nanomaterials, but also provide new insights for embedded cooling and significant energy savings on power devices.

Neuromorphic systems based on memristor arrays have not only addressed the von Neumann bottleneck issue but have also enabled the development of computing applications with high accuracy. In this study, an artificial neural architecture based on a 10 × 10 IGZO memristor array is presented to emulate synaptic dynamics for performing artificial intelligence (AI) computing with high recognition accuracy rate. The large area 10 × 10 IGZO memristor array was fabricated using the photolithography method, resulting in stable and reliable memory operations. The bipolar switching at −2 V–2.5 V, endurance of 500 cycles, retention of >10⁴ s, and uniform V_set/V_reset operation of 100 devices were achieved by modulating the oxygen vacancy in the IGZO film. The emulation of electric synaptic dynamics was also observed, including potentiation-depression, multilevel long-term memory (LTM), and multilevel short-term memory (STM), revealing highly linear and stable synaptic functions at different modulated pulse settings. Additionally, electrical modeling (HSPICE) with vector-matrix measurements and simulation of various artificial neural network (ANN) algorithms, such as convolution neural network (CNN) and spiking neural network (SNN), were performed, demonstrating a linear increase in current accumulation with high recognition rates of 99.33 % and 86.46 %, respectively. This work provides a novel approach for overcoming the von Neumann bottleneck issue and emulating synaptic dynamics in various neural networks with high accuracy.

The penetration of nanocarriers across the blood-brain barrier (BBB) through transcellular transcytosis is difficult owing to their lysosomal degradation after endocytosis. This obstacle prevents the targeted delivery of siRNAs in the treatment of glioma or other brain diseases. In this study, endoplasmic reticulum (ER) membranes derived from glioma cells were used to fabricate the integrative hybrid nanoplexes (EhCv/siRNA NPs) for enhancing the penetration efficiency of crossing BBB through transcytosis. Compared to undecorated Cv/siRNA NPs, the ER membrane-decorated EhCv/siRNA NPs evaded lysosomal degradation through a non-degradable endosome-Golgi/ER pathway, resulting in a significantly stronger ability to cross the BBB through transcellular transcytosis and better gene-silencing effects of siRNAs in U87 glioma in vitro and in vivo. Altogether, this study is valuable for designing the optimized non-degradable transcellular transcytosis across the blood-brain barrier and advancing drug delivery to brain.