Solar-driven interfacial evaporation holds great potential for seawater desalination, yet its efficiency and long-term viability are critically hindered by salt crystallization. Herein, we develop a spiral-layered hydrogel (SLH) solar evaporator to overcome these persistent challenges. The SLH features a layered architecture with non-uniform pore sizes across its upper and lower layers, ensuring adequate water supply to the evaporation interface while minimizing heat loss to the bulk water. Coupled with high light absorption and reduced evaporation enthalpy, the SLH achieves an impressive evaporation rate of 4.7 kg m^-2 h^-1. The Janus structure of the SLH suppresses salt crystallization on the surface, while the omnidirectional groove configuration and spiral flow dynamics synergistically prevent salt ion accumulation within the pores. Furthermore, the electronegativity of graphdiyne (GDY) surface together with conjugate two-dimensional plane, act as a barrier to chloride ion infiltration. In a 20 wt% NaCl solution, the cost-effective SLH maintains a robust evaporation rate of 4.23 kg m^-2 h^-1 over an extended period of 20 days. Outdoor validation with a cylindrical prototype demonstrated a maximum freshwater collection rate of 1.8 L m^-2 h^-1. Such functional design and salt management strategy may provide possible prescriptions to salt accumulation challenges, establishing a foundation for sustainable and high-efficiency water production systems.

Two-dimensional (2D) MoTe₂ shows great potential for future semiconductor devices, but the lab-to-fab transition is still in its preliminary stage due to the constraints in the crystal growth level. Currently, the chemical vapor deposition growth of 2D MoTe₂ primarily relies on the tellurization process of Mo-source precursor (MSP). However, the target product 2H-MoTe₂ from Mo precursor suffers from long growth time and suboptimal crystal quality, and MoO_x precursor confronts the dilemma of unclear growth mechanism and inconsistent growth products. Here, we developed magnetron-sputtered MoO₃ film for fast and high-mobility 2H-MoTe₂ growth. The solid-to-solid phase transition growth mechanism of 2D MoTe₂ from Mo and MoO_x precursor was first experimentally unified, and the effect mechanism of MSPs on 2D MoTe₂ growth was systematically elucidated. Compared with Mo and MoO₂, the MoO₃ precursor has the least Mo-unit lattice deformation and exhibits the optimal crystal quality of growth products. Meanwhile, the lowest Gibbs free energy change of the chemical reaction results in an impressive 2HMoTe₂ growth rate of 8.07 μm/min. The constructed 2H-MoTe₂ field-effect transistor array from MoO₃ precursor showcases record-high hole mobility of 85 cm²·V^-1·s^-1, competitive on-off ratio of 3×10⁴, and outstanding uniformity. This scalable method not only offers efficiency but also aligns with industry standards, making it a promising guideline for diverse 2D material preparation towards real-world applications.

The cognition of spatiotemporal tactile stimuli, including fine spatial stimuli and static/dynamic temporal stimuli, is paramount for intelligent robots to feel their surroundings and complete manipulation tasks. However, current tactile sensors have restrictions on simultaneously demonstrating high sensitivity and performing selective responses to static/dynamic stimuli, making it a challenge to effectively cognize spatiotemporal tactile stimuli. Here, we report a high-sensitive and self-selective humanoid mechanoreceptor (HMR) that can precisely respond to spatiotemporal tactile stimuli. The HMR with PDMS/chitosan@CNTs (PDMS: polydimethylsiloxane; CNT: carbon nanotube) graded microstructures and polyurethane hierarchical porous spacer exhibits high sensitivity of 3790.8 kPa⁻¹. The HMR demonstrates self-selective responses to static and dynamic stimuli with mono signal through the hybrid of piezoresistive and triboelectric mechanisms. Consequently, it can respond to spatiotemporal tactile stimuli and generate distinguishable and multi-type characteristic signals. With the assistance of the convolutional neural network, multiple target objects can be easily identified with a high accuracy of 99.1%. This work shows great potential in object precise identification and dexterous manipulation, which is the basis of intelligent robots and natural human-machine interactions.

Two-dimensional (2D) semiconductors, especially transition metal dichalcogenides (TMDCs), have been proven to be excellent channel materials for the next-generation integrated circuit (IC). However, the contact problem between 2D TMDCs and metal electrodes has always been one of the main factors restricting their development. In this review, we summarized recent work on 2D TMDCs contact from the perspective of compatible integration with silicon processes and practical application requirements, including the contact performance evaluation indicators, special challenges encountered in 2D TMDCs, and recent optimization methods. Specifically, we sorted out and highlighted the performance indicators of 2D TMDCs contacts, including contact resistance (R_C), contact scaling, contact stability, and contact electrical/thermal conductivity. Special challenges of 2D TMDCs and metal contact, such as severe Fermi level pinning, large R_C, and difficult doping, are systematically discussed. Furthermore, typical methods for optimizing 2D TMDCs R_C, edge contact strategies for scaling contact lengths, and solutions for improving contact stability are reviewed. Based on the current research and problems, the development direction of 2D TMDCs contacts that meet the silicon-based compatible process and application performance requirements is proposed.

Monolayer two-dimensional (2D) semiconductors are emerging as top candidates for the channels of the future chip industry due to their atomically thin body and superior immunity to short channel effect. However, the low saturation current caused by the high contact resistance (R_c) in monolayer MoS₂ field-effect transistors (FETs) limits ultimate electrical performance at scaled contact lengths, which seriously hinders application of monolayer MoS₂ transistors. Here we present a scalable strategy with a clean end-bond contact scheme that leads to size-independent electrodes and ultralow contact resistance of 2.5 kΩ·μm to achieve record high performances of saturation current density of 730 μA·μm^-1 at 300 K and 960 μA·μm^-1 at 6 K. Our end-bond contact strategy in monolayer MoS₂ FETs enables the great potential for atomically thin integrated circuitry.

van der Waals (vdW) heterostructures based on two-dimensional (2D) materials holding design-by-demand features offer astonishing opportunities to construct novel electronics and optoelectronics devices due to the vdW force interaction between their stacked components. At the atomically thin confinement, vdW heterostructure not only exhibits unprecedented properties as an entire counterpart, but also provides unique platforms to manipulate the vdW interfacial behaviors. Therefore, developing characterization techniques to comprehensively understand the coupling effect on structure-property-performance relationship of vdW heterostructures is crucial for fundamental science and practical applications. Here, we focus on the most widely studied 2D semiconductor transition metal dichalcogenides (TMDCs) and systematically review significant advances in characterizing the material and interfacial coupling effect of the related vdW heterostructures. Specially, we will discuss microscopy techniques for unveiling the structure-property relationship of vdW heterostructures and optical spectroscopy measurements for analyzing vdW interfacial coupling effect. Finally, we address some promising strategies to optimize characterization technologies for resolving vdW heterostructures, including coupling multiple characterization technologies, improving temporal and spatial resolution, developing fast, efficient, and non-destructive techniques and introducing artificial intelligence.

The dangling bond free nature of two-dimensional (2D) material surface/interface makes van der Waals (vdW) heterostructure attractive for novel electronic and optoelectronic applications. But in practice, edge is unavoidable and could cause band bending at 2D material edge analog to surface/interface band bending in conventional three-dimensional (3D) materials. Here, we report a first principle simulation on edge band bending of free standing MoS₂/WS₂ vdW heterojunction. Due to the imbalance charges at edge, S terminated edge causes upward band bending while Mo/W terminated induces downward bending in undoped case. The edge band bending is comparable to band gap and could obviously harm electronic and optoelectronic properties. We also investigate the edge band bending of electrostatic doped heterojunction. N doping raises the edge band whereas p doping causes a decline of edge band. Heavy n doping even reverses the downward edge band bending at Mo/W terminated edge. In contrast, heavy p doping doesn’t invert the upward bending to downward. Comparing with former experiments, the expected band gap narrowing introduced by interlayer potential gradient at edge is not observed in our free-standing structures and suggests substrate’s important role in this imbalance charge induced phenomenon.

Since the invention of the triboelectric nanogenerator (TENG) in 2012, it has become one of the most vital innovations in energy harvesting technologies. The TENG has seen enormous progress to date, particularly in applications for energy harvesting and self-powered sensing. It starts with the simple working principles of the triboelectric effect and electrostatic induction, but can scavenge almost any kind of ambient mechanical energy in our daily life into electricity. Extraordinary output performance optimization of the TENG has been achieved, with high area power density and energy conversion efficiency. Moreover, TENGs can also be utilized as self-powered active sensors to monitor many environmental parameters. This review describes the recent progress in mainstream energy harvesting and self-powered sensing research based on TENG technology. The birth and development of the TENG are introduced, following which structural designs and performance optimizations for output performance enhancement of the TENG are discussed. The major applications of the TENG as a sustainable power source or a self-powered sensor are presented. The TENG, with rationally designed structures, can convert irregular and mostly low-frequency mechanical energies from the environment, such as human motion, mechanical vibration, moving automobiles, wind, raindrops, and ocean waves. In addition, the development of self-powered active sensors for a variety of environmental simulations based on the TENG is presented. The TENG plays a great role in promoting the development of emerging Internet of Things, which can make everyday objects connect more smartly and energy-efficiently in the coming years. Finally, the future directions and perspectives of the TENG are outlined. The TENG is not only a sustainable micro-power source for small devices, but also serves as a potential macro-scale generator of power from water waves in the future.

Magnetic metals (Fe, Co, Ni) and alloys thereof are easily synthesized as nanoparticles, but obtaining highly dispersed graphene-based magnetic nanomaterials remains challenging. Here, three CoNi/graphene nanocomposites (CoNi/GN) are successfully assembled for the first time via a one-pot strategy without templating by manipulating the reaction time and solvents used for the same precursors. Moreover, the reduction of graphene oxide utilizing this method is more effective than that by conventional methods and the alloy particles are firmly embedded on the GN substrate. Compared to n- and p-CoNi/GN nanocomposites, o-CoNi/GN nanocomposites show the best electromagnetic wave absorption properties with the maximum reflection loss of-31.0 dB at 4.9 GHz for a thickness of 4 mm; the effective absorption bandwidth (< 10.0 dB) is 7.3 GHz (9.5–16.8 GHz) for a thickness of 2 mm. The structures and electromagnetic wave absorption mechanisms of the three composites were also investigated. This research provides a new platform for the development of magnetic alloy nanoparticles in the field of microwave-absorbing devices.

Methylammonium lead halide perovskites have been reported to be promising candidates for high-performance photodetectors. However, self-powered broadband ultraviolet-visible-near infrared (UV-Vis-NIR) photodetection with high responsivity is difficult to achieve in these materials. Here, we demonstrate, for the first time, a novel trilayer hybrid photodetector made by combining an n-type Si wafer, TiO₂ interlayer and perovskite film. By precisely controlling the thickness of the TiO₂ layer, enhanced separation and reduced recombination of carriers at the Si–perovskite interface are obtained. As a result, perovskite film, when combined with a low-bandgap Si, extends the wavelength range of photo response to 1, 150 nm, along with improved on/off ratio, responsivity, and specific detectivity, when compared to pristine perovskite. Results obtained in this work are comparable or even better than those reported for perovskite-based UV-Vis-NIR photodetectors. In particular, the hybrid photodetectors can operate in a self-powered mode. The mechanism of enhancement has been explored and it is found that the increased separation and reduced recombination of photogenerated carriers at the junction interface leads to the improved performance.