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Organometal halide perovskite synaptic devices are fabricated; they emulate important working principles of a biological synapse, including excitatory postsynaptic current, paired-pulse facilitation, short-term plasticity, long-term plasticity, and spike-timing dependent plasticity. These properties originate from possible ion migration in the ion-rich perovskite matrix. This work has extensive applicability and practical significance in neuromorphic electronics.

Highly crystalline SnO₂ is demonstrated to serve as a stable and robust electron-transporting layer for high-performance perovskite solar cells. Benefiting from its high crystallinity, the relatively thick SnO₂ electron-transporting layer (≈120 nm) provides a respectable electron-transporting property to yield a promising power conversion efficiency (PCE)(18.8%) Over 90% of the initial PCE can be retained after 30 d storage in ambient with ≈70% relative humidity.

B. A. Grzybowski and co-workers develop a novel approach to magnetofluidic tweezing, described on page 3453. This approach overcomes several limitations of other tweezing modalities and allows the controlled assembly of small particles into various static and dynamic structures: the image depicts the generation of colloidal crystals.

For the first time, two types of highly anisotropic, highly transparent wood composites are demonstrated by taking advantage of the macro-structures in original wood. These wood composites are highly transparent with a total transmittance up to 90% but exhibit dramatically different optical and mechanical properties.

A new concept for junction fabrication by connecting multiple regions with varying layer thicknesses, based on the thickness dependence, is demonstrated. This type of junction is only possible in super-thin-layered 2D materials, and exhibits similar characteristics as p–n junctions. Rectification and photovoltaic effects are observed in chemically homogeneous MoSe₂ junctions between domains of different thicknesses.

Printed flexible photodetectors based on 2D inorganic perovskites with atomic thickness show excellent photosensing with fast rise and decay response times. As-synthesized nanosheets can easily be dispersed in various solvents, leading to large-area, crack-free, low-roughness, flexible films after printing. This study demonstrates that all-inorganic perovskite CsPbX₃ nanosheets as a new class of 2D semiconductors have huge potential for flexible optoelectronic applications.

Methanol is a very useful platform molecule and liquid fuel. Electrocatalytic reduction of CO₂ to methanol is a promising route, which currently suffers from low efficiency and poor selectivity. Herein we report the first work to use a Mo-Bi bimetallic chalcogenide (BMC) as an electrocatalyst for CO₂ reduction. By using the Mo-Bi BMC on carbon paper as the electrode and 1-butyl-3-methylimidazolium tetrafluoroborate in MeCN as the electrolyte, the Faradaic efficiency of methanol could reach 71.2 % with a current density of 12.1 mA cm⁻², which is much higher than the best result reported to date. The superior performance of the electrode resulted from the excellent synergistic effect of Mo and Bi for producing methanol. The reaction mechanism was proposed and the reason for the synergistic effect of Mo and Bi was discussed on the basis of some control experiments. This work opens a way to produce methanol efficiently by electrochemical reduction of CO₂.

MoBi thin: Mo-Bi bimetallic chalcogenide nanosheets were utilized as an electrocatalyst for CO₂ reduction to produce methanol. The Faradaic efficiency (FE) could reach 71.2 % with a current density of 12.1 mA cm⁻² in 0.5 m [Bmim]BF₄ MeCN solution, which are the highest values to date.

Rhenium disulfide (ReS₂) is attracting more and more attention for its thickness-depended direct band gap. As a new appearing 2D transition metal dichalcogenide, the studies on synthesis method via chemical vapor deposition (CVD) is still rare. Here a systematically study on the CVD growth of continuous bilayer ReS₂ film and single crystalline hexagonal ReS₂ flake, as well as their corresponding optoelectronic properties is reported. Moreover, the growth mechanism has been proposed, accompanied with simulation study. High-performance photodetector based on ReS₂ flake shows a high responsivity of 604 A·W⁻¹, high external quantum efficiency of 1.50 × 10⁵ %, and fast response time of 2 ms. ReS₂ film-based photodetector exhibits weaker performance than the flake one; however, it still demonstrates a much faster response time (≈10³ ms) than other reported CVD-grown ReS₂-based photodetector (≈10⁴–10⁵ ms). Such good properties of ReS₂ render it a promising future in 2D optoelectronics.

Hexagonal single-crystal ReS₂ flakes and large-area continuous polycrystalline bilayer ReS₂ film are achieved via CVD method, and their possible growth mechanism is studied. Potential utilization of ReS₂ in high performance photodetector is explored. A single-crystal ReS₂-based photodetector is found to be of excellent photoresponsivity (604 A W⁻¹), high external quantum efficiency (1.50 × 10⁵%), and fast response time (2 ms), obviously superior to many other similar transition-metal-dichalcogenide-based photodetectors.

The development of renewable energy storage and conversion devices is one of the most promising ways to address the current energy crisis, along with the global environmental concern. The exploration of suitable active materials is the key factor for the construction of highly efficient, highly stable, low-cost and environmentally friendly energy storage and conversion devices. The ability to prepare two-dimensional (2D) metal dichalcogenide (MDC) nanosheets and their functional composites in high yield and large scale via various solution-based methods in recent years has inspired great research interests in their utilization for renewable energy storage and conversion applications. Here, we will summarize the recent advances of solution-processed 2D MDCs and their hybrid nanomaterials for energy storage and conversion applications, including rechargeable batteries, supercapacitors, electrocatalytic hydrogen generation and solar cells. Moreover, based on the current progress, we will also give some personal insights on the existing challenges and future research directions in this promising field.

Two-dimensional (2D) metal dichalcogenides (MDC) and their functional composites show great potential in a wide range of applications. Solution-based methods can produce high-yield 2D MDC-based materials for energy storage/conversion applications. Recent advances regarding the energy storage/conversion applications of solution-processed 2D MDC-based materials, including rechargeable batteries, supercapacitors, electrocatalytic hydrogen generation, and solar cells, are summarized.

As the properties of ultrathin two-dimensional (2D) crystals are strongly related to their electronic structures, more and more attempts were carried out to tune their electronic structures to meet the high standards for the construction of next-generation smart electronics. Herein, for the first time, we show that the conductive nature of layered ternary chalcogenide with formula of Cu₂WS₄ can be switched from semiconducting to metallic by hydrogen incorporation, accompanied by a high increase in electrical conductivity. In detail, the room-temperature electrical conductivity of hydrogenated-Cu₂WS₄ nanosheet film was almost 10¹⁰ times higher than that of pristine bulk sample with a value of about 2.9×10⁴ S m⁻¹, which is among the best values for conductive 2D nanosheets. In addition, the metallicity in the hydrogenated-Cu₂WS₄ is robust and can be retained under high-temperature treatment. The fabricated all-solid-state flexible supercapacitor based on the hydrogenated-Cu₂WS₄ nanosheet film shows promising electrochemical performances with capacitance of 583.3 F cm⁻³ at a current density of 0.31 A cm⁻³. This work not only offers a prototype material for the study of electronic structure regulation in 2D crystals, but also paves the way in searching for highly conductive electrodes.

Metallic nanosheets: The conductivity of the layered ternary chalcogenide Cu₂WS₄ is switched from semiconducting to metallic by hydrogen incorporation, accompanied by a strong increase in conductivity. The metallic hydrogenated-Cu₂WS₄ nanosheets were applied as electrode material in an all-solid-state flexible supercapacitor.