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Nickel phosphides (Ni2P) have been proposed as advanced anode materials for a lithium-ion battery (LIB) due to its high capacity and electrochemical activity. However, the large volume expansion and poor cycling stability limit the practical applications of a Ni2P based LIB. In this work, we report a one-step strategy to prepare Ni2P@C nanoparticles embedded in echinus-like porous carbon (Ni2P@C@EPC) as a promising anode for LIB. It is demonstrated that the Ni2P@C@EPC corresponds the hexagonal Ni2P phase very well. The Raman spectrum indicates that the defective carbon is dominant in Ni2P@C@EPC. Moreover, Ni2P@C@EPC possesses a high specific surface area of 372.953 cm2 · g−1 with an average pore size of 6.496 nm. Remarkably, the EPC plays a significant role in realizing high and stable performance by confining the reaction between Ni2P and Li+, facilitating Li+ diffusion mobility and inhibiting the volume change in charge/discharge. As a result, the Ni2P@C@EPC delivers a high specific capacity of 807.7 mAh · g−1 at 0.2 A · g−1, excellent rate capability (592.1, 455.9, 346.1, 236.4 and 160.69 mAh · g−1 at 0.1, 0.2, 0.5, 1.0 and 2.0 A · g−1), and long cycling stability (464.8 mAh · g−1 at 0.2 A · g−1 after 100 cycles). Moreover, the structure evolution upon cycling as well as electrochemical analysis has verified the superiority of Ni2P@C@EPC anode. [ABSTRACT FROM AUTHOR]

Heteroatom doped carbon nanomaterials are often employed as advanced anodes for lithium ion batteries (LIBs) because of their stable structure, high capacity and low cost. In this work, we proposed a novel strategy to synthesize high density (N, Ni, P) tri-doped echinus-like porous carbon spheres (PCS) by carbonizing a metal-organophosphine framework (MOPF) directly. The MOPF employs riboflavin sodium phosphate (C17H20N4NaO9P) as an organic ligand as well as a nitrogen and phosphorus source to conjugate with Ni(NO3)2 · 6H2O. As an anode for LIBs, PCS was demonstrated with discharge capacities that were able to reach 386.5 mAh · g−1 after 100 cycles at a current density of 0.05 A · g−1. Besides, the stable reversible capacities were obtained from ∼459 mAh · g−1 to ∼91.8 mAh · g−1 when the current density was varied from 0.05 to 1 A · g−1. The good anode performance is attributed to the unique structure of PCS and (N, Ni, P) tri-doping which introduces the additional capacities due to the presence of the 'reservoir effect'. Moreover, the electrochemical analysis implied that the surface-limited capacitive behavior dominantly contributes to the lithium ion storage capacity of the PCS anode. [ABSTRACT FROM AUTHOR]

Silicon is a promising alternative anode material since it has a ten times higher theoretical specific capacity than that of a traditional graphite anode. However, the poor cycling stability due to the huge volume change of Si during charge/discharge processes has seriously hampered its widespread application. To address this challenge, we design a silicon hollow sphere nanostructure by selective etching and a subsequent magnesiothermic reduction. The Si hollow spheres exhibit enhanced electrochemical properties compared to the commercial Si nanoparticles. The initial discharge and charge capacities of the Si hollow sphere anode are 2215.8 mAh g−1 and 1615.1 mAh g−1 with a high initial coulombic efficiency (72%) at a current density of 200 mA g−1, respectively. In particular, the reversible capacity is 1534.5 mAh g−1 with a remarkable 88% capacity retention against the second cycle after 100 cycles, over four times the theoretical capacity of the traditional graphite electrode. Therefore, our work demonstrates the considerable potential of silicon structures for displacing commercial graphite, and might open up new opportunities to rationally design various nanostructured materials for lithium ion batteries. [ABSTRACT FROM AUTHOR]

We report a scanning focused laser technique for pixel-by-pixel activation of the screen-printed carbon nanotube cathodes for field emission flat panel displays. The turn-on and working field of the cathodes became as low as 1.96 V µm[?]1 and 2.70 V µm[?]1, respectively, after 57 kW cm[?]2 laser irradiation. The current density even reached 4.00 mA cm[?]2 at 2.90 V µm[?]1, which was 1285 times larger than the untreated one. This dramatic enhancement is due to the fact that the focused laser can remove not only the surface contamination, but can change the geometric structure of the treated pixel as well. More importantly, these laser activated carbon nanotube cathodes show much more uniform field emission performances, as required by flat panel displays. [ABSTRACT FROM AUTHOR]

We theoretically propose a design of core–shell nanoparticles consisting of a dielectric core coated by several alternating plasmonic and dielectric shell layers for the generation of comb-like scattering resonances. We demonstrate that the obtained scattering resonances are independent of the polarization, observation angle and background medium, since they originate from the unconventional Fano interference between Mie modes with the same multipole moment inside each plasmonic shell layer. Furthermore, we also demonstrate that controlling either the core or the shell parameters can precisely tune the spectral positions of the comb-like resonances. At last, we show that the comb-like resonances can be well maintained even for the non-perfect spherical core–shell nanoparticles. All these features make the proposed multilayered core–shell nanoparticles attractive candidates for multichannel and ultrasensitive optical tags. [ABSTRACT FROM AUTHOR]

InN has received considerable attentions due to its small band-gap and unique properties in the III-nitride family. Understanding the effects of defects on optoelectronic properties of InN nanowire is essential for exploring its applications in future nanodevices. In this work, we have systematically calculated defect states in InN nanowires based on density-functional theory. Hydrogen passivation and several potential intrinsic point defects are considered in various sizes of nanowires, as well as charged defect states. For small-sized hexagonal nanowires, VN at N-poor condition or NIn at N-rich condition is the most stable defect. Whereas for larger-sized nanowires, VN and InN defects are competing when the N chemical potential changes, showing obvious size effect of the defect stability on the nanowire surface. Those defect states change the electronic structure of the nanowires drastically by introducing empty bands or deep level and provide possibility to tailor the optical properties in terms of forming different stable defects. [ABSTRACT FROM AUTHOR]

We report a potential efficient fluorescent label based on the dyed dielectric-metal core–shell resonators (DMCSRs). By utilizing the near-field coupling between the dyes and the multipolar sharp cavity plasmon resonances, the dyed DMCSRs with diameter of 1.02 μm are demonstrated to be capable of supporting multiple spontaneous emission peaks with the linewidths as narrow as ∼ 10 nm in visible range, and these reshaped fluorescent emissions are insensitive to the surrounding dielectric environment. Furthermore, these multiple narrow emission peaks show a precise tunability on the spectrum by simply separating a nanometric dielectric layer between the dielectric core and the metallic shell, which may provide an attractive spectral multiplexing strategy in the fields of cell biology and medical sciences. [ABSTRACT FROM AUTHOR]

In this paper, we report on the design and observation of double Fano resonances (DFRs) in an individual symmetry-reduced nanostructure and the induced high sensing sensitivity. Such a plasmonic nanostructure consists of a partially overlapped double-metallic nanotriangles with unequal sizes fabricated by using fast and low-cost angle-resolved nanosphere lithography. Symmetry breaking generates two narrow quadrupolar dark modes, which further enhance the coupling with fundamental bright dipole modes within the same structure, manifesting the effect of DFRs. The resonance wavelength and line shape of DFRs can be tailored by changing the degree of asymmetry as well as the size of the designed nanostructure. Based on DFRs, a high sensitivity to dielectric environment with a maximum figure of merit of 35 is measured. Due to a fast manufacturing process with high reproducibility and high structural tunability, the fabricated individual metallic nanostructure provides an opportunity for significant potential applications in localized surface plasmon resonance based single or double-wavelength sensors in the near-infrared region. [ABSTRACT FROM AUTHOR]