Hygroelectricity is proposed as a means to produce electric power from air by absorbing gaseous or vaporous water molecules, which are ubiquitous in the atmosphere. Here, using a synergy between a hygroscopic bulk graphene oxide with a heterogeneous structure and interface mediation between electrodes/materials with Schottky junctions, we develop a high-performance hygroelectric generator unit with an output voltage approaching 1.5 V. High voltage (e.g., 18 V with 15 units) can be easily reached by simply scaling up the number of hygroelectric generator units in series, enough to drive commercial electronic devices. This work provides insight for the design and development of hygroelectric generators that may promote the efficient conversion of potential energy in the environmental atmosphere to electricity for practical applications.

A high-performance moisture triggered nanogenerator is fabricated by using graphene quantum dots (GQDs) as the active material. GQDs are prepared by direct oxidation and etching of natural graphite powder, which have small sizes of 2-5 nm and abundant oxygen-containing functional groups. After the treatment by electrochemical polarization, the GQDs-based moisture triggered nanogenerator can deliver a high voltage up to 0.27 V under 70% relative humidity variation, and a power density of 1.86 mW cm with an optimized load resistor. The latter value is much higher than the moisture-electric power generators reported previously. The GQD moisture triggered nanogenerator is promising for self-power electronics and miniature sensors.

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The extinction spectra of five silver equilateral triangle plates with a fixed thickness of 10 nm and side lengths of 50, 100, 150, 200 ,and 250 nm, respectively, have been simulated by the discrete dipole approximation (DDA) method in which a geometric object of interest is meshed and represented by a lattice of spatial dipoles. Irradiated by an incident plane wave with a given propagation direction and polarization state, each triangle nanoplate presents three surface plasmon resonance (SPR) peaks in the range of 300 to 1200 nm. At a given peak, every complex spatial oscillatory vector derived by DDA (corresponding to a certain dipole in the meshed target) is orthogonally resolved into three basic oscillations. Each basic component can be subsequently expressed by two parameters, amplitude (P) and phase angle (varphi). The distributions of six such physical parameters of all the dipoles in the selected cross plane of the target are illustrated colorfully in plots as a graphic characterization and assignment of the SPR modes. The graphic method is applied to reveal the local fine features of SPR modes. And it provides direct evidence for classifying SPR peaks which belong to different triangle nanoplates and appear at different wavelengths. Three SPR modes are recognized graphically and the wavelengths of SPR peaks are found to have linear relationships with the side lengths of the triangle nanoplates.

Many novel applications of silver become possible if silver nanotubes can be produced reliably and easily. A simple, template‐assisted procedure is reported here. The Figure shows a scanning electron microscopy image of one of the silver nanotubes, which was broken by ultrasonic vibration, demonstrating that the nanostructure is indeed a hollow nanotube and showing that the nanotube is formed of (crystalline) nanoparticles.