Multi-shelled Nanostructures Research Articles

Investigated numerically nanoshell thickness on photothermal response of hybrid nanostructures in an aqueous medium

The current study describes the effect of changing a shell thickness on photothermal response of a hybrid nanostructures, using theoretical investigation based on the Finite Element Method (FEM) of the COMSOL multi-physics program. The hybrid nanostructures are the Core/Shell nanoparticles (C/S NPs) and the Core/Multi-Shell nanoparticles (C/MS NPs), with fixed core diameter (30 nm) and variable shell thickness (10–20 nm) to create a new type of hybrid nanostructures usable in photonic and optoelectronic applications. For these hybrid nanostructures, gold (Au) and silver (Ag) as a partner of titanium dioxide (TiO2) were used in thermo-plasmonic part. Hybrid multi-shell nanostructures consist of silver-gold and gold-silver sandwich with titanium dioxide shell in between, all of which are dispersed in an aqueous medium (n = 1.33). The optical properties, the local field distribution, and local heating control of plasmonic nanostructures have been studied under the influence of illumination at plasmonic wavelengths (405, and 532 nm). The results revealed to a clear tunable and adjustable optical and thermo-plasmonic properties by controlling the structure of the core/shell NPs. This results can be enhanced by changing the shell thickness, shape, size, and the nanostructure. The temperature elevation of the core/shell NPs was about 1–5 °C under different wavelengths of laser irradiation. Based on those results, there is possibility of using the core/shell nanoparticles as an efficient heat source in many applications, such as in the sterilization and disinfection of medical equipments.

Bifunctional metal-organic framework-derived nitrogen-doped porous multishell CuCoS@NiCoS nanospheres for supercapacitors and hydrogen evolution reactions

Transition metal sulfide porous multishell nanostructures with high active sites have great potential for application as bifunctional materials. Herein, bifunctional metal-organic framework (MOF)-derived nitrogen-doped porous multishell CuCoS@NiCoS (N–CCS@NCS) nanospheres are synthesized on Cu–Co–O substrates. The tightly connected nanocluster particles transformed by MOFs have more active sites and surface area. The ion transport efficiency between the shell layers is improved and the resistance to ion transport is further reduced. Moreover, the porous multishell structure provides a buffer space for the shock generated by multiple rapid embedding/de-embedding of OH− ions and offered a stable structure. Interestingly, the number of shell layers, thickness, spacing, and shell density of the N–CCS@NCS nanospheres can be controlled by adjusting the Ni content. Owing to its compositional and structural advantages, the N–CCS@NCS electrode exhibited a high specific capacitance of 1259 F g−1 at 0.5 A g−1. The assembly N–CCS@NCS//activated carbon asymmetrical supercapacitor exhibited specific energy of 87.3 W h kg−1 at 825 W kg−1 and a capacitance retention rate of 81.3 % after 8400 cycles. Furthermore, the N–CCS@NCS electrocatalyst exhibited outstanding hydrogen precipitation properties (254 mV at 10 mA cm−2) in 1 M KOH and excellent stability over 20 h. Therefore, MOF-derived porous multishell metal sulfides are promising candidates for supercapacitor and hydrogen evolution reaction dual applications.

The design and synthesis of spinel one-dimensional multi-shelled nanostructures for Li-ion batteries.

The rational design, synthesis, and massive production of one-dimensional (1D) spinel composite oxides with multi-shelled nanostructures are critical for the realization of highly efficient energy conversion and storage. However, owing to the limitations of the synthetic methods, the 1D multi-shelled nanostructures, especially for multi-element oxides and binary-metal oxides, have been rarely fabricated. Herein, we design a facile and general method to fabricate 1D spinel composite oxides with complex architectures. It is found that the concentration of the precursor polymer PAN can control the structures of the products at optimal heating rate, including hollow nanofibers, wire-in-tube nanofibers, and tube-in-tube nanofibers. This technique could be extended to various inorganic multi-element oxides and binary-metal oxides. Moreover, numerous twin boundaries (TBs) are found to form in the Co0.5Ni0.5Fe2O4 tube-in-tube nanofibers. Benefiting from both large porosity and TBs structures, the tube-in-tube hollow nanostructures are measured to possess superior electrochemical performances with high energy and stability in lithium-ion storage.

Enhanced dye-sensitized up-conversion luminescence of neodymium-sensitized multi-shell nanostructures

The predecessor of China Optics was China Optics and Applied Optics Digest, which was founded in 1985. At that time, it was the only retrieval journal in the field of optics in China. At the end of 2008, China Optics and Applied Optics Digest was renamed

Construction of complex NiS multi-shelled hollow structures with enhanced sodium storage

Hybrid multi-shelled nanostructures with tailored shell architectures have shown great promise for electrochemical energy storage applications. However, formation of such designed delicate architectures remains a great challenge. Here, starting from metal-organic frameworks (MOFs), we report a facile and straightforward, in situ chemical transformation strategy, to fabricate a Ni@NCNTs hybrid multi-shelled structure with complex shell architecture. Then, a promising anode material consisting of NiS nanocrystals embedded in multi-shelled hollow microspheres (MSHMs) interlinked by N-doped carbon nanotubes (NCNTs) was prepared through the manipulation of template engaged reaction by using the urea and yolk-shelled Ni-MOFs precursor. The rationally designed NiS@NCNT MSHMs not only provide sufficient electrode/electrolyte contact area, short mass/charge transfer distances and improve the electron transportation efficiency, but also release the volume expansion effectively owing to the multi-cavities within the hollow structure. Benefiting from the unique structural merits, the NiS@NCNT MSHMs yields a high reversible specific capacity of 531.5 mAh g−1 at 0.05 A g−1, stable cycling with 89.3% capacity retention over 500 cycles at 1 A g−1, and excellent rate capability. In addition, in situ XRD reveals that the initial sodium storage processes in NiS is based on an intercalation reaction, then a two-step conversion reaction. Our work reveals the importance of rational design and synthesis of multi-shelled hollow nanostructures with higher complexity for improved electrochemical performance.

PtFe nanoparticles supported on electroactive Au–PANI core@shell nanoparticles for high performance bifunctional electrocatalysis

Efficient bifunctional electrocatalytic activity for reduction and oxidation reactions based on the AuNP@PANI@PtFe core–multishell nanostructures is presented. The AuNP@PANI@PtFe exhibits an enhanced catalytic activity and durability for ORR and MOR than conventional carbon supported Pt catalysts.

ZnSe/CdS/CdSe triple-sensitized ZnO nanowire arrays for multi-bandgap photoelectrochemical hydrogen generation

Since the discovery of hydrogen evolution through the photoelectrochemical (PEC) splitting of water from n-type TiO2 electrodes, the technology of short-bandgap semiconductors (such as ZnSe, CdS and CdSe) combined with one-dimensional (1D) metal-oxide nanowire (NW) arrays (e.g., TiO2 and ZnO) to enhance their visible-light harvest efficiency has been widely studied. In this study, ZnSe/CdS/CdSe triple-sensitized ZnO NW arrays were successfully fabricated on FTO substrates via a facile hydrothermal and anion exchange reaction, followed by a chemical bath deposition (CBD) approach. Through the effective synergistic light absorption of the solar energy and the multi-type-II graded bandgap level between the core ZnO NW and the different photosensitization out layers in these composite nanostructures, a remarkable enhancement in photochemical conversion performance was achieved. The morphogenetic strategy used for the material production in this work is low-cost but effective, and it could be extended to prepare other core–multishell nanostructures with elaborate textural characteristics.

Higher Order Tunable Fano Resonances in Multilayer Nanocones

We present a computational study of the plasmonic response of a gold–silica–gold multilayered nanostructure based on truncated nanocones. Symmetry breaking is introduced by rotating the nanostructure and by offsetting the layers. Nanocones with coaxial multilayers show dipole–dipole Fano resonances with resonance frequencies depending on the polarization of the incident light, which can be changed by rotating the nanostructure. By breaking the axial symmetry, plasmonic modes of distinct angular momenta are strongly mixed, which provide a set of unique and higher order tunable Fano resonances. The plasmonic response of the multilayered nanocones is compared to that of multishell nanostructures with the same volume and the former are discovered to render visible high-order dark modes and to provide sharp tunable Fano resonances. In particular, higher order tunable Fano resonances arising in non-coaxial multilayer nanocones can vary the plasmon lines at various spectral regions simultaneously, which makes these nanostructures greatly suitable for plasmon line shaping both in the extinction and near field spectra.