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Skin-mountable microelectronics are garnering substantial interest for various promising applications including human-machine interfaces, biointegrated devices, and personalized medicine. However, it remains a critical challenge to develop e-skins to mimic the human somatosensory system in full working range. Here, we present a multifunctional e-skin system with a heterostructured configuration that couples vinyl-hybrid-silica nanoparticle (VSNP)-modified polyacrylamide (PAM) hydrogel with two-dimensional (2D) MXene through nano-bridging layers of polypyrrole nanowires (PpyNWs) at the interfaces, featuring high toughness and low hysteresis, in tandem with controlled crack generation and distribution. The multidimensional configurations endow the e-skin with an extraordinary working range (2800%), ultrafast responsiveness (90 ms) and resilience (240 ms), good linearity (800%), tunable sensing mechanisms, and excellent reproducibility. In parallel, this e-skin platform is capable of detecting, quantifying, and remotely monitoring stretching motions in multiple dimensions, tactile pressure, proximity sensing, and variations in temperature and light, establishing a promising platform for next-generation smart flexible electronics.

Metallic molybdenum disulfide (MoS2), e.g., 1T phase, is touted as a highly promising material for energy storage that already displays a great capacitive performance. However, due to its tendency to aggregate and restack, it remains a formidable challenge to assemble a high-performance electrode without scrambling the intrinsic structure. Here, we report an electrohydrodynamic-assisted fabrication of 3D crumpled MoS2 (c-MoS2) and its formation of an additive-free stable ink for scalable inkjet printing. The 3D c-MoS2 powders exhibited a high concentration of metallic 1T phase and an ultrathin structure. The aggregation-resistant properties of the 3D crumpled particles endow the electrodes with open space for electrolyte ion transport. Importantly, we experimentally discovered and theoretically validated that 3D 1T c-MoS2 enables an extended electrochemical stable working potential range and enhanced capacitive performance in a bivalent magnesium-ion aqueous electrolyte. With reduced graphene oxide (rGO) as the positive electrode material, we inkjet-printed 96 rigid asymmetric micro-supercapacitors (AMSCs) on a 4-in. Si/SiO2 wafer and 100 flexible AMSCs on photo paper. These AMSCs exhibited a wide stable working voltage of 1.75 V and excellent capacitance retention of 96% over 20 000 cycles for a single device. Our work highlights the promise of 3D layered materials as well-dispersed functional materials for large-scale printed flexible energy storage devices.

Stable lithium–sulfur batteries (LSBs) have promise to shape a new generation of stable energy-storage devices. Although the energy densities of LSBs (up to 2500 W h kg−1) are higher than those of conventional Li-ion batteries (LIBs), lithium polysulfides (LiPSs) shuttling remains a pressing issue that leads to irreversible loss of active materials, degraded capacity, and eroded durability of LSBs. To tackle this issue, in this study we modified commercial polypropylene (PP) or pristine separators by laminating them with a layer of crumpled MoS2 (c-MoS2) nanosheets; the resulting assembly is referred to herein as MC-separator. We synthesized the c-MoS2 nanosheets using a special electrohydrodynamic process and laminated them onto the PP separator through simple vacuum filtration. The synthesized c-MoS2 nanosheets featured a metallic 1T-phase enriched with strained sulfur vacancies and a high surface area, providing additional redox reaction sites for LiPSs during battery operations. The c-MoS2 thin film could adsorb the LiPSs while providing additional reaction sites to reutilize these LiPSs, ultimately enhancing the specific capacity of the battery. When operated at a rate of 0.5C, a cell comprising a sulfur-expanded graphite cathode, the MC separator, and a Li anode provided a high specific capacity (1242 mA h g−1) with approximately 96% coulombic efficiency over 500 cycles. In contrast, a cell prepared with a PP separator, when operated at 0.5C, provided an initial capacity of only 746 mA h g−1 and could be run for only 296 cycles. The high capacity and good cycling stability of our new cell indicate that the MC separator could suppress the LiPSs shuttle effect, allowing better utilization of the active materials even at high C rates. [ABSTRACT FROM AUTHOR]

Architected materials that actively respond to external stimuli hold tantalizing prospects for applications in energy storage, wearable electronics, and bioengineering. Molybdenum disulfide, an excellent two-dimensional building block, is a promising candidate for lithium-ion battery anode. However, the stacked and brittle two-dimensional layered structure limits its rate capability and electrochemical stability. Here we report the dewetting-induced manufacturing of two-dimensional molybdenum disulfide nanosheets into a three-dimensional foam with a structural hierarchy across seven orders of magnitude. Our molybdenum disulfide foam provides an interpenetrating network for efficient charge transport, rapid ion diffusion, and mechanically resilient and chemically stable support for electrochemical reactions. These features induce a pseudocapacitive energy storage mechanism involving molybdenum redox reactions, confirmed by in-situ X-ray absorption near edge structure. The extraordinary electrochemical performance of molybdenum disulfide foam outperforms most reported molybdenum disulfide-based Lithium-ion battery anodes and state-of-the-art materials. This work opens promising inroads for various applications where special properties arise from hierarchical architecture. The stacked and brittle 2D layered structure of molybdenum disulphide limits its practical application in lithium ion batteries. Here, authors report a dewetting-induced manufacture strategy to create the interpenetrating network and induce the pseudocapacity to improve the electrochemical performance. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) semiconducting monolayers such as transition metal dichalcogenides (TMDs) are promising channel materials to extend Moore's Law in advanced electronics. Synthetic TMD layers from chemical vapor deposition (CVD) are scalable for fabrication but notorious for their high defect densities. Therefore, innovative endeavors on growth reaction to enhance their quality are urgently needed. Here, we report that the hydroxide W species, an extremely pure vapor phase metal precursor form, is very efficient for sulfurization, leading to about one order of magnitude lower defect density compared to those from conventional CVD methods. The field-effect transistor (FET) devices based on the proposed growth reach a peak electron mobility ~200 cm2/Vs (~800 cm2/Vs) at room temperature (15 K), comparable to those from exfoliated flakes. The FET device with a channel length of 100 nm displays a high on-state current of ~400 µA/µm, encouraging the industrialization of 2D materials. Chemical vapor deposition enables the scalable production of 2D semiconductors, but the grown materials are usually affected by high defect densities. Here, the authors report a hydroxide vapour phase deposition method to synthesize wafer-scale monolayer WS2 with reduced defect density and electrical properties comparable to those of exfoliated flakes. [ABSTRACT FROM AUTHOR]

The bulk photovoltaic effect (BPVE) in ferroelectrics, wherein spontaneous polarization can be reversed within crystals lacking centrosymmetry, encompasses the significant contribution of ferroelectric domain walls (DWs), known as DW‐PVE. Nevertheless, the separation between intrinsic BPVE within the domain and DW‐PVE remains unexplored in 2D ferroelectrics, notwithstanding its significant importance. In this study, sizable crystals of 2D ferroelectric SnS are successfully grown, facilitating a comprehensive yet intricate examination of domain configurations utilizing polarized optical microscopy and piezoresponse force microscopy. By properly selecting the large ferroelectric single domain within SnS crystals, uniform intrinsic BPVE across the domain is unequivocally demonstrated. Furthermore, to further enhance intrinsic BPVE, manipulation of strain poling increased photocurrent, suggesting that locally distributed polarizations due to imperfection introduced in SnS crystals are aligned by strain. These results will offer a new avenue for rigorous comprehension of DW‐PVE in 2D ferroelectrics. [ABSTRACT FROM AUTHOR]

Absorption of photons in atomically thin materials has become a challenge in the realization of ultrathin, high-performance optoelectronics. While numerous schemes have been used to enhance absorption in 2D semiconductors, such enhanced device performance in scalable monolayer photodetectors remains unattained. Here, we demonstrate wafer-scale integration of monolayer single-crystal MoS 2 photodetectors with a nitride-based resonant plasmonic metasurface to achieve a high detectivity of 2.58 × 10 12 Jones with a record-low dark current of 8 pA and long-term stability over 40 days. Upon comparison with control devices, we observe an overall enhancement factor of >100; this can be attributed to the local strong EM field enhanced photogating effect by the resonant plasmonic metasurface. Considering the compatibility of 2D semiconductors and hafnium nitride with the Si CMOS process and their scalability across wafer sizes, our results facilitate the smooth incorporation of 2D semiconductor-based photodetectors into the fields of imaging, sensing, and optical communication applications.

Metallic molybdenum disulfide (MoS 2 ), e . g ., 1T phase, is touted as a highly promising material for energy storage that already displays a great capacitive performance. However, due to its tendency to aggregate and restack, it remains a formidable challenge to assemble a high-performance electrode without scrambling the intrinsic structure. Here, we report an electrohydrodynamic-assisted fabrication of 3D crumpled MoS 2 (c-MoS 2 ) and its formation of an additive-free stable ink for scalable inkjet printing. The 3D c-MoS 2 powders exhibited a high concentration of metallic 1T phase and an ultrathin structure. The aggregation-resistant properties of the 3D crumpled particles endow the electrodes with open space for electrolyte ion transport. Importantly, we experimentally discovered and theoretically validated that 3D 1T c-MoS 2 enables an extended electrochemical stable working potential range and enhanced capacitive performance in a bivalent magnesium-ion aqueous electrolyte. With reduced graphene oxide (rGO) as the positive electrode material, we inkjet-printed 96 rigid asymmetric micro-supercapacitors (AMSCs) on a 4-in. Si/SiO 2 wafer and 100 flexible AMSCs on photo paper. These AMSCs exhibited a wide stable working voltage of 1.75 V and excellent capacitance retention of 96% over 20 000 cycles for a single device. Our work highlights the promise of 3D layered materials as well-dispersed functional materials for large-scale printed flexible energy storage devices.