With the depletion of fossil fuels and the increasing demand of energy for economic development, it is urgent to develop renewable energy technologies to sustain the economic growth. Electrospinning is a versatile and efficient fabrication method for one-dimensional (1D) nanostructured fibers of metals, metal oxides, hydrocarbons, composites, and so forth. The resulting nanofibers (NFs) with controllable diameters ranging from nanometer to micrometer scale possess unique properties such as a high surface-area-to-volume and aspect ratio, low density, and high pore volume. These properties make 1D nanomaterials more advantageous than conventional materials in energy harvesting, conversion, and storage devices. In this review, the key parameters for e-spinning are discussed and the properties of electrospun NFs and applications in solar cells, fuel cells, nanogenerators, hydrogen energy harvesting and storage, lithium-ion batteries, and supercapacitors are reviewed. The advantages and disadvantages of electrospinning and an outlook on the possible future directions are also discussed.

Direct laser-reduction of graphene oxide (GO), as a lithography-free approach, has been proven effective in manufacturing in-plane micro-supercapacitors (MSCs) with fast ion diffusion.

Nanoscale control over the second-order photon correlation function g (2) (τ ) is critical to emerging research in nonlinear nanophotonics and integrated quantum information science. Here we report on quasiparticle control of photon bunching with g (2) (0) > 45 in the cathodoluminescence of nanodiamond nitrogen vacancy (NV 0 ) centers excited by a converged electron beam in an aberrationcorrected scanning transmission electron microscope. Plasmon-mediated NV 0 cathodoluminescence exhibits a 16-fold increase in luminescence intensity correlated with a three fold reduction in photon bunching compared with that of uncoupled NV 0 centers. This effect is ascribed to the excitation of single temporally uncorrelated NV 0 centers by single surface plasmon polaritons. Spectrally resolved Hanbury Brown-Twiss interferometry is employed to demonstrate that the bunching is mediated by the NV 0 phonon sidebands, while no observable bunching is detected at the zero-phonon line. The data are consistent with fast phonon-mediated recombination dynamics, a conclusion substantiated by agreement between Bayesian regression and Monte Carlo models of superthermal NV 0 luminescence.PACS numbers: 42.50. Ar, 78.60.Hk, 73.20.Mf The efficiency of second-order nonlinearities scales proportionally with g (2) (0), the second-order photon correlation function at zero delay of the driving optical field [1,2]. Nanoscale superthermal light sources exhibiting photon bunching with g (2) (0) > 2 thus provide a path toward high-efficiency nonlinear nanophotonics. Moreover, control of g (2) (τ ) is increasingly critical for quantum nanophotonics applications [3,4]. However, despite increasing evidence of coherent quantum behavior in nanoplasmonic systems [5,6], experimental plasmonic control of g (2) (τ ) has been realized only in Purcell enhancement of the anti-bunching dynamics of plasmoncoupled emitters [7].Compared with photoluminescence (PL) spectroscopy, cathodoluminescence (CL) yields vastly improved spatial resolution in measurements of g (2) (τ ). This fact was leveraged in the first explorations of CL photon statistics, in which photon antibunching was observed from individual NV 0 centers in nanodiamonds and from point defects in hexagonal boron nitride excited by an 80-keV electron beam [8-10]. More critically, photon bunching has been observed in the CL of ensembles of quantum emitters * Matthew.Feldman@vanderbilt.edu † lawriebj@ornl.gov whose PL exhibits g (2) (τ ) ≈ 1 because of the absence of temporal correlations between optically excited emitters. In contrast to PL, the scanning transmission electron microscope (STEM) primarily excites higher-energy modes, such as the 30-eV bulk plasmon in diamond [11]. The subsequent cascading excitation of multiple excitons and color centers for each plasmon, within an ∼ 10 fs excitation window, explains recent observations of photon bunching of g (2) (0) − 1 > 4 in CL spectroscopy of ensembles of NV 0 centers in nanodiamond [12,13]. However, understanding the classical and quantum optical proper...