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Abstract Manipulating the stoichiometric distribution along depth direction is a promising technique to modulate the optical and optoelectronic properties of the mid-infrared sensitive lead chalcogenides at room temperature. Here, we demonstrate an optoelectronic sensitization method based on O+ beam implantation at 50 kV for polycrystalline PbSe, which can manipulate the depth profile and hence the structural properties to modulate the optical and the optoelectronic performances. Unlike the diffused material presented in previous works, the resulting material is nano-polycrystalline with average grain sizes of 17.1–29.3 nm. The optoelectronic characterizations indicate that the optoelectronic properties can indeed be modulated by the implantation dose. The responsivity up to 2.09 A/W at 4 μm has been obtained at room temperature from the sample with implantation dose of 1 × 1018 cm−2. Comparing with the diffusion counterpart, the ion prepared PbSe nanomaterial exhibits completely different structural, compositional, optical, and electrical properties. The high responsivity of this material is attributed to the high optical absorption and carrier mobility induced by O+ beam. However, the high dark current has been also observed in this material, mainly due to its low inherent potential barrier height between crystallites. Graphical abstract Image 1 Highlights • An ion beam technology for preparing mid-infrared photosensitive PbSe nanomaterial has been presented. • Enhanced optical absorption, carrier mobility and photo-responsivity have been induced by this technology. • The low potential barrier height between crystallites of this nanomaterial is caused by its small particle sizes. • The microstructure and the optoelectronic properties can be modulated by the implantation dose. [ABSTRACT FROM AUTHOR]

High specific surface area (SSA) and optimized porous structures are necessary for supercapacitors electrodes. MOFs have porous structure which make them potential candidates for electrodes materials. Here, a MOF derivative with Ni@NiOx nanoparticles embedded in porous carbon nanosheets (Ni@NiOx/C) is prepared by hydrothermal method and carbonization process. Among them, the porous structure is tuned by the ZnO templates. Results show that the amount of doped ZnO nanoparticles can affect the morphology, porous structure and electrochemical properties of Ni@NiOx/C nanosheets electrodes. In three electrode system, the Ni@NiOx/C-2 electrode has a high specific capacitance of 752 F g−1 (at 1 A g−1) and prominent rate performance (the initial capacitance retains 56% when the current density increased to 100 A g−1). After 10,000 cycles, 99% of the initial capacitance is maintained. The assembled asymmetric device (Ni@NiOx/C-2//AC) also exhibits a high-power density (15,840 W kg−1). • The MOF derived Ni@NiOx/C materials possess tunable porous structure. • The effect of ZnO doping on the pore size distribution is analyzed in detail. • The highest specific capacitance of the electrodes is 752 F g−1. • The electrode displays excellent cyclic stability. [ABSTRACT FROM AUTHOR]

Sodium-ion batteries (SIBs) have evolved into the most potential alternatives to lithium-ion batteries (LIBs) especially for large-scale energy storage applications. However, the large radius of sodium ion inevitably causes large volume change and sluggish ion diffusion kinetics. Molybdenum disulfide (MoS 2) as a rising star of anode for SIBs has raised concern because of its high theoretical capacity. Nevertheless, MoS 2 suffers from low electronic conductivity and serious re-stacking, resulting in declined cycling stability and poor rate capability. Herein, we reported an electrostatic self-assembly process to synthesize three-dimensional (3D) crumpled MXene-bonded MoS 2 nanosheets. The MoS 2 /MXene heterostructure not only avoids the serious self-aggregation of MoS 2 nanoparticles but only maintains the chemical and mechanical stability of MoS 2 /MXene hybrids during sodiation and desodiation. Strong chemical interactions were validated on the interface of MXene and MoS 2 , favoring fast charge transfer kinetics and durable structural stability. The developed MoS 2 /MXene electrode exhibits a high specific capacity (509 mAh g−1 at 0.05 A g−1) and considerable cyclability (326 mAh g−1 at 1 A g−1 after 900 cycles), manifesting a promising application prospect for SIBs. Our work can provide a rational strategy for the electrode design strategy for SIBs. [Display omitted] • Crumpled MXene bonded MoS 2 nanosheets demonstrate a brilliant performance as SIB anode materials. • The synergistic effect of crumpled MXene and MoS 2 nanosheets, greatly facilitates electron and mass transfer. • The MoS 2 /MXene electrode behaves fast sodium diffusion rate and favorable electrochemical kinetics. [ABSTRACT FROM AUTHOR]

Abstract: Monoclinic bismuth vanadate (m-BiVO4) micro-/nanostructures with different sizes and morphologies were successfully prepared via a facile and rapid microwave and ultrasonic wave combined technique. The obtained BiVO4 products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and UV–vis diffuse reflection spectroscopy (DRS). It was found that the solvent and pH value had a significant influence on morphology, size and crystalline structure of the product. Nut-like, potato-like and broccoli-like monoclinic BiVO4 were fabricated in different solvents. The crystal phase could be modulated by varying the pH value of reaction system. The photocatalytic activities of the products were also evaluated by the degradation of Rhodamine B (RhB) under visible light irradiation. The result revealed that the photocatalytic activities of BiVO4 nanostructures were closely related to the crystalline phase, band gap and particle size. Monoclinic BiVO4 nanoparticles with small crystal size and large band gap exhibited remarkable photocatalytic performance. [Copyright &y& Elsevier]