Infomat最新文献

The fast booming of wearable electronics provides great opportunities for intelligent gas detection with improved healthcare of mining workers, and a variety of gas sensors have been simultaneously developed. However, these sensing systems are always limited to single gas detection and are highly susceptible to the inference of ubiquitous moisture, resulting in less accuracy in the analysis of gas compositions in real mining conditions. To address these challenges, we propose a synergistic strategy based on sensor integration and machine learning algorithms to realize precise NH₃ and NO₂ gas detections under real mining conditions. A wearable sensing array based on the graphene and polyaniline composite is developed to largely enhance the sensitivity and selectivity under mixed gas conditions. Further introduction of backpropagation neural network (BP-NN) and partial least squares (PLS) algorithms could improve the accuracy of gas identification and concentration prediction and settle the inference of moisture, realizing over 99% theoretical prediction level on NH₃ and NO₂ concentrations within a wide relative humidity range, showing great promise in real mining detection. As proof of concept, a wireless wearable bracelet, integrated with sensing arrays and machine-learning algorithms, is developed for wireless real-time warning of hazardous gases in mines under different humidity conditions.

Outstanding charge transport in molecular crystals is of great importance in modern electronics and optoelectronics. The widely adopted strategies to enhance charge transport, such as restraining intermolecular vibration, are mostly limited to organic molecules, which are nearly inoperative in 2D inorganic molecular crystals currently. In this contribution, charge transport in 2D inorganic molecular crystals is improved by integrating charge-delocalized Se₈ rings as building blocks, where the delocalized electrons on Se₈ rings lift the intermolecular orbitals overlap, offering efficient charge transfer channels. Besides, α-Se flakes composed of charge-delocalized Se₈ rings possess small exciton binding energy. Benefitting from these, α-Se flake exhibits excellent photodetection performance with an ultrafast response rate (~5 μs) and a high detectivity of 1.08 × 10¹¹ Jones. These findings contribute to a deeper understanding of the charge transport of 2D inorganic molecular crystals composed of electron-delocalized inorganic molecules and pave the way for their potential application in optoelectronics.

Near-infrared (NIR) luminescent metal halide (LMH) materials have attracted great attention in various optoelectronic applications due to their low-temperature solution-processable synthesis, abundant crystallographic/electronic structures, and unique optoelectronic properties. However, some challenges still remain in their luminescence design, performance improvement, and application assignments. This review systematically summarizes the development of NIR LMHs through classifying NIR luminescent origins into four major categories: band-edge emission, self-trapped exciton (STE) emission, ion emission, and defect-related emission. The luminescence mechanisms of different types of NIR LMHs are discussed in detail by analyzing typical examples. Reasonable strategies for designing and optimizing luminescence/optoelectronic properties of NIR LMHs are summarized, including bandgap engineering, self-trapping state engineering, chemical composition modification, energy transfer, and other auxiliary strategies such as improvement of synthesis scheme and post-processing. Furthermore, application prospects based on the optoelectronic devices are revealed, including phosphor-converted light-emitting diodes (LEDs), electroluminescent LEDs, photodetectors, solar cells, and x-ray scintillators, as well as demonstrations of some related practical applications. Finally, the existing challenges and future perspectives on the development of NIR LMH materials are critically proposed. This review aims to provide general understanding and guidance for the design of high-performance NIR LMHs materials.

The inherent unpredictability of the maritime environment leads to low rates of survival during accidents. Life jackets serve as a crucial safety measure in underwater environments. Nonetheless, most conventional life jackets lack the capability to monitor the wearer's underwater body movements, impeding their effectiveness in rescue operations. Here, we present an intelligent self-powered life jacket system (SPLJ) composed of a wireless body area sensing network, a set of deep learning analytics, and a human condition detection platform. Six coaxial core-shell structure triboelectric fiber sensors with high sensitivity, stretchability, and flexibility are integrated into this system. Additionally, a portable integrated circuit module is incorporated into the SPLJ to facilitate real-time monitoring of the wearer's movement. Moreover, by leveraging the deep-learning-assisted data analytics and establishing a robust correlation between the wearer's movements and condition, we have developed a comprehensive system for monitoring drowning individuals, achieving an outstanding recognition accuracy of 100%. This groundbreaking work introduces a fresh approach to underwater intelligent survival devices, offering promising prospects for advancing underwater smart wearable devices in rescue operations and the development of ocean industry.

In order to fulfill the complex cognitive behaviors in neuromorphic systems with reduced peripheral circuits, the reliable electronic synapses mimicked by single device that achieves diverse long-term and short-term plasticity are essential. Phase change random access memory (PCRAM) is of great potential for artificial synapses, which faces, however, difficulty to realize short-term plasticity due to the long-lasting resistance drift. This work reports the ruthenium-doped Ge₂Sb₂Te₅ (RuGST) based PCRAM, demonstrating a series of synaptic behaviors of short-term potentiation, pair-pulse facilitation, long-term depression, and short-term plasticity in the same single device. The optimized RuGST electronic synapse with the high transformation temperature of hexagonal phase >380°C, the outstanding endurance >10⁸ cycles, the low resistance drift factor of 0.092, as well as the extremely high linearity with correlation coefficients of 0.999 and 0.976 in parts of potentiation and depression. Further investigations also go insight to mechanisms of Ru doping according to thorough microstructure characterization, revealing that Ru dopant is able to enter GST lattices thus changing and stabilizing atomic arrangement of GST. This leads to the short-term plasticity realized by RuGST PCRAM. Eventually, the proposed RuGST electronic synapses performs a high accuracy of ~94.1% in a task of image recognition of CIFAR-100 database using ResNet 101. This work promotes the development of PCRAM platforms for large-scale neuromorphic systems.

This review article summarizes the exciting advancements in liquid crystalline MXenes and guidance for their processing into versatile macro-architectures suitable for various applications.

Protonic solid oxide electrolysis cell combined with intermittent renewable energy is a promising green hydrogen production technology.

The oxidation chemistry of two-dimensional transition metal carbide MXenes has brought new research significance to their protection and application. However, the oxidation behavior and degradation mechanism of MXenes, in particular with time under oxygen conditions at room temperature, remain largely unexplored. Here, several experimental and theoretical techniques are used to determine a very early stage of the oxidation mechanism of HF-etched Ti₃C₂T_x (a major member of MXenes and T_x = surface functional groups) in an oxygen environment at room temperature. Aberration-corrected environmental transmission electron microscopy coupled with reactive molecular dynamics simulations show that the crystal plane-dependent oxidation rate of Ti₃C₂T_x and oxide expansion are attributed to differences in the coordination and charge of superficial Ti atoms, and the existence of the channels between neighboring MXene layers on the different crystal planes. The complementary x-ray photoelectron spectroscopy and Raman spectroscopy analyses indicate that the anatase and a tiny fraction of brookite TiO₂ successively precipitate from the amorphous region of oxidized Ti₃C₂T_x, grow irregularly and transform to rutile TiO₂. Our study reveals the early-stage structural evolution of MXenes in the presence of oxygen and facilitates further tailoring of the MXene performance employing oxidation strategy.

The regulation of carrier generation and transport by Schottky junctions enables effective optoelectronic conversion in optoelectronic devices. A simple and general strategy to spontaneously generate photocurrent is of great significance for self-powered photodetectors but is still being pursued. Here, we propose that a photocurrent can be induced at zero bias by the transmittance contrast of MXene electrodes in MXene/semiconductor Schottky junctions. Two MXene electrodes with a large transmittance contrast (84%) between the thin and thick zones were deposited on the surface of a semiconductor wafer using a simple and robust solution route. Kelvin probe force microscopy tests indicated that the photocurrent at zero bias could be attributed to asymmetric carrier generation and transport between the two Schottky junctions under illumination. As a demonstration, the MXene/GaN ultraviolet (UV) photodetector exhibits excellent performance superior to its counterpart without transmittance contrast, including high responsivity (81 mA W^–1), fast response speed (less than 31 and 29 ms) and ultrahigh on/off ratio (1.33 × 10⁶), and good UV imaging capability. Furthermore, this strategy has proven to be universal for first- to third-generation semiconductors such as Si and GaAs. These results provide a facile and cost-effective route for high-performance self-powered photodetectors and demonstrate the versatile and promising applications of MXene electrodes in optoelectronics.

The exceptional properties of two-dimensional (2D) magnet materials present a novel approach to fabricate functional magnetic tunnel junctions (MTJ) by constructing full van der Waals (vdW) heterostructures with atomically sharp and clean interfaces. The exploration of vdW MTJ devices with high working temperature and adjustable functionalities holds great potential for advancing the application of 2D materials in magnetic sensing and data storage. Here, we report the observation of highly tunable room-temperature tunneling magnetoresistance through electronic means in a full vdW Fe₃GaTe₂/WSe₂/Fe₃GaTe₂ MTJ. The spin valve effect of the MTJ can be detected even with the current below 1 nA, both at low and room temperatures, yielding a tunneling magnetoresistance (TMR) of 340% at 2 K and 50% at 300 K, respectively. Importantly, the magnitude and sign of TMR can be modulated by a DC bias current, even at room temperature, a capability that was previously unrealized in full vdW MTJs. This tunable TMR arises from the contribution of energy-dependent localized spin states in the metallic ferromagnet Fe₃GaTe₂ during tunnel transport when a finite electrical bias is applied. Our work offers a new perspective for designing and exploring room-temperature tunable spintronic devices based on vdW magnet heterostructures.