2D van der Waals (vdW) magnets, which present intrinsic ferromagnetic/antiferromagnetic ground states at finite temperatures down to atomic‐layer thicknesses, open a new horizon in materials science ...and enable the potential development of new spin‐related applications. The layered structure of vdW magnets facilitates their atomic‐layer cleavability and magnetic anisotropy, which counteracts spin fluctuations, thereby providing an ideal platform for theoretically and experimentally exploring magnetic phase transitions in the 2D limit. With reduced dimensions, the susceptibility of 2D magnets to a large variety of external stimuli also makes them more promising than their bulk counterpart in various device applications. Here, the current status of characterization and tuning of the magnetic properties of 2D vdW magnets, particularly the atomic‐layer thickness, is presented. Various state‐of‐the‐art optical and electrical techniques have been applied to reveal the magnetic states of 2D vdW magnets. Other emerging 2D vdW magnets and future perspectives on the stacking strategy are also given; it is believed that they will excite more intensive research and provide unprecedented opportunities in the field of spintronics.
2D van der Waals (vdW) magnets, which present intrinsic ferromagnetic/antiferromagnetic ground states down to atomiclayer thicknesses, open a new horizon in materials science. Recent state‐of‐the‐art characterization and tuning of the magnetic properties of 2D vdW magnets are outlined. Future perspectives and emerging 2D vdW magnets are also discussed, to provide unprecedented opportunities in the fields of spintronics.
Although only a few 2D materials have been predicted to possess ferroelectricity, 2D ferroelectrics are expected to play a dominant role in the upcoming nano era as important functional materials. ...The ferroelectric properties of 2D ferroelectrics are significantly different than those of traditional bulk ferroelectrics owing to their intrinsic size and surface effects. To date, 2D ferroelectrics have been reported to exhibit diverse properties ranging from bulk photovoltaic and piezoelectric/pyroelectric effects to the spontaneous valley and spin polarization. These properties are either dependent on ferroelectric polarization or coupled with it for easy electric control, thus making 2D ferroelectrics applicable to multifunctional nanodevices. At present, cumulative efforts are being made to explore 2D ferroelectrics in theories, experiments, and applications. Herein, such theories and methods are briefly introduced. Subsequently, intrinsic and extrinsic origins of 2D ferroelectricity are separately summarized. In addition, invented or laboratory‐validated 2D ferroelectric‐based applications are listed. Finally, the existing challenges and prospects of 2D ferroelectrics are discussed.
2D ferroelectrics are expected to play a dominant role in the upcoming nano era as important functional materials. Relevant theories, as well as intrinsic and extrinsic 2D ferroelectrics, are outlined. Further, the existing challenges and prospects of the exploration in 2D ferroelectrics are also discussed, which should provide unprecedented opportunities in the fields of electronics, spintronics, optoelectronics, and valleytronics.
As an emerging subclass of 2D materials, Xenes (e.g., borophene, silicene, germanene, stanene, phosphorene, arsenene, antimonene, and bismuthene) consist of one single element and have opened the ...door for various important applications. Benefiting from their impressive characteristics, including ultrathin folded structure, ultrahigh surface–volume ratio, excellent mechanical strength and flexibility, Xenes are considered as promising electrode materials in the field of electrochemical energy with large capacity, high rate, and high safety. This review provides a comprehensive summary of selected properties, synthetic challenges, and the latest theoretical and experimental advances in the energy‐related applications of Xenes, including Li/Na ion batteries, Li–S batteries, electrocatalysis, and supercapacitors. Finally, the challenges and outlook of this emerging field are discussed.
The 2D monoelemental family (Xenes) and their fundamental electrochemistry are comprehensively reviewed and discussed. Strategies and challenges on engineering heterostructures, defects, encapsulation, modification of Xenes are deeply summarized. The relationship/interaction among fundamental electrochemistry, electrocatalysis, and energy storage (Li/Na ion batteries, Li/Na air batteries, supercapacitors, Li–S battery) is concluded and outlooked.
Atomically ordered intermetallic nanoparticles exhibit improved catalytic activity and durability relative to random alloy counterparts. However, conventional methods with time‐consuming and ...high‐temperature syntheses only have rudimentary capability in controlling the structure of intermetallic nanoparticles, hindering advances of intermetallic nanocatalysts. We report a template‐directed strategy for rapid synthesis of Pd‐based (PdM, M=Pb, Sn and Cd) ultrathin porous intermetallic nanosheets (UPINs) with tunable sizes. This strategy uses preformed seeds, which act as the template to control the deposition of foreign atoms and the subsequent interatomic diffusion. Using the oxygen reduction reaction (ORR) as a model reaction, the as‐synthesized Pd3Pb UPINs exhibit superior activity, durability, and methanol tolerance. The favored geometrical structure and interatomic interaction between Pd and Pb in Pd3Pb UPINs are concluded to account for the enhanced ORR performance.
This template‐directed synthetic strategy is a universal route for shape‐controlled synthesis of intermetallic nanocrystals and will provide new opportunities for intermetallic nanocatalysts.
Type II porous liquids are demonstrated to be promise porous materials. However, the category of porous hosts is very limited. Here, a porous host metal–organic polyhedra (MOP‐18) is reported to ...construct type II porous liquids. MOP‐18 is dissolved into 15‐crown‐5 as an individual cage (5 nm). Both the molecular dynamics simulations and experimental gravimetric CO2 solubility test indicate that the inner cavity of MOP‐18 in porous liquids is unoccupied by 15‐crown‐5 and is accessible to CO2. Thus, the prepared porous liquids show enhanced gas solubility. Furthermore, the prepared porous liquid is encapsulated into graphene oxide (GO) nanoslits to form a GO‐supported porous liquid membrane (GO‐SPLM). Owing to the empty cavity of MOP‐18 unit cages in porous liquids that reduces the gas diffusion barrier, GO‐SPLM significantly enhances the permeability of gas.
A type II porous liquid is constructed by using MOP‐18 and 15‐crown‐5 as the porous host and bulky solvent, respectively. The existence of permanent porosity in porous liquid is confirmed by both the molecular dynamics simulations and experimental date. The unoccupied cavity in the porous liquid can be used for gas storage and facilitating the gas transportation.
The in‐depth understanding of ions' generation and movement inside all‐inorganic perovskite quantum dots (CsPbBr3 QDs), which may lead to a paradigm to break through the conventional von Neumann ...bottleneck, is strictly limited. Here, it is shown that formation and annihilation of metal conductive filaments and Br− ion vacancy filaments driven by an external electric field and light irradiation can lead to pronounced resistive‐switching effects. Verified by field‐emission scanning electron microscopy as well as energy‐dispersive X‐ray spectroscopy analysis, the resistive switching behavior of CsPbBr3 QD‐based photonic resistive random‐access memory (RRAM) is initiated by the electrochemical metallization and valance change. By coupling CsPbBr3 QD‐based RRAM with a p‐channel transistor, the novel application of an RRAM–gate field‐effect transistor presenting analogous functions of flash memory is further demonstrated. These results may accelerate the technological deployment of all‐inorganic perovskite QD‐based photonic resistive memory for successful logic application.
Resistive random‐access memory (RRAM) and RRAM‐functionalized field‐effect transistors (FETs) based on photon tunable CsPbBr3 quantum dots are demonstrated. The formation and annihilation of metal conductive filaments and bromine‐vacancy filaments in CsPbBr3 quantum dot arrays can be realized under an electric field and light irradiation. The devices exhibit multilevel data storage using light tuning, which may accelerate the technological deployment of all‐inorganic perovskite QD‐based photonic memory.
The demands for waste heat energy recovery from industrial production, solar energy, and electronic devices have resulted in increasing attention being focused on thermoelectric materials. Over the ...past two decades, significant progress is achieved in inorganic thermoelectric materials. In addition, with the proliferation of wireless mobile devices, economical, efficient, lightweight, and bio‐friendly organic thermoelectric (OTE) materials have gradually become promising candidates for thermoelectric devices used in room‐temperature environments. With the development of experimental measurement techniques, the manufacturing for nanoscale thermoelectric devices has become possible. A large number of studies have demonstrated the excellent performance of nanoscale thermoelectric devices, and further improvement of their thermoelectric conversion efficiency is expected to have a significant impact on global energy consumption. Here, the development of experimental measurement methods, theoretical models, and performance modulation for nanoscale OTE materials are summarized. Suggestions and prospects for the future development of these devices are also provided.
Organic thermoelectric (OTE) devices play an important role in developing novel thermoelectric devices. Here, the progresses of nanoscale OTE devices from the aspects of structural, materials, measurement, and theoretical methods, as well as some typical optimization strategies are reviewed, and an outlook is given to provide an inspiration for the future development of OTE devices.
2D materials hold promising potential for novel gas separation. However, a lack of in‐plane pores and the randomly stacked interplane channels of these membranes still hinder their separation ...performance. In this work, ferrocene based‐MOFs (Zr‐Fc MOF) nanosheets, which contain abundant of in‐plane micropores, are synthesized as porous supports to fabricate Zr‐Fc MOF supported ionic liquid membrane (Zr‐Fc‐SILM) for highly efficient CO2 separation. The micropores of Zr‐Fc MOF nanosheets not only provide extra paths for CO2 transportation, and thus increase its permeance up to 145.15 GPU, but also endow the Zr‐Fc‐SILM with high selectivity (216.9) of CO2/N2 through the nanoconfinement effect, which is almost ten times higher than common porous polymer SILM. Furthermore, based on the photothermal‐responsive properties of Zr‐Fc MOF, the performance is further enhanced (35%) by light irradiation through a photothermal heating process. This provides a brand new way to design light facilitating gas separation membranes.
Highly efficient SILM for CO2 separation is prepared by using photothermal‐responsive ferrocene based‐MOFs as porous supports. The in‐plane pores of Zr‐Fc MOF provide extra paths for CO2 transportation, and thus increase its permeance, which can be further enhanced through a photothermal modulation mechanism.
High‐performance photonic nonvolatile memory combining photosensing and data storage with low power consumption ensures the energy efficiency of computer systems. This study first reports in situ ...derived phosphorene/ZnO hybrid heterojunction nanoparticles and their application in broadband‐response photonic nonvolatile memory. The photonic nonvolatile memory consistently exhibits broadband response from ultraviolet (380 nm) to near infrared (785 nm), with controllable shifts of the SET voltage. The broadband resistive switching is attributed to the enhanced photon harvesting, a fast exciton separation, as well as the formation of an oxygen vacancy filament in the nano‐heterojunction. In addition, the device exhibits an excellent stability under air exposure compared with reported pristine phosphorene‐based nonvolatile memory. The superior antioxidation capacity is believed to originate from the fast transfer of lone‐pair electrons of phosphorene. The unique assembly of phosphorene/ZnO nano‐heterojunctions paves the way toward multifunctional broadband‐response data‐storage techniques.
A solution‐processed phosphorene/ZnO nano‐heterojunction is demonstrated. Light‐tunable broadband resistive switching from UV to NIR is realized through the novel optoelectronic coupling of ZnO and phosphorene in resistive random access memory (RRAM). Superior environmental tolerance together with a synergetic photovoltaic and photogating effect paves the way of this attractive material for next‐generation photonic RRAM devices.
Carrot-inspired solar thermal evaporator Long, Yaojia; Huang, Shaolong; Yi, Huan ...
Journal of materials chemistry. A, Materials for energy and sustainability,
2019, Letnik:
7, Številka:
47
Journal Article
Recenzirano
Solar steam generation appears as an emerging green strategy due to its potential applications in water desalination, power generation and chemical purification. Although a variety of efforts have ...been devoted to developing high-efficiency solar steam generation devices, a number of challenges remain, including the relatively low thermal efficiency, the complicated process, the high cost, and the difficulty in cycling. Herein, inspired by the natural water transportation in plants, a cheap carrot-inspired solar thermal evaporator (ethanol-treated-carrot biochar, ECB) has been reported by utilizing its inherent structure, which achieves a record high evaporation rate of 2.04 kg m
−2
h
−1
and an apparent energy conversion efficiency of 127.8% under one-sun illumination. The inherent structure not only enables sufficient water transportation, but also offers a high light-to-heat conversion efficiency originating from the carbonized surface. Furthermore, the excellent durability and environmental stability of the biochar allow for convenient recycling programs and practical applications.
A carrot-inspired solar thermal evaporator exhibits a water evaporation rate of 2.04 kg m
−2
h
−1
and an outstanding durability and stability.
