Energy Harvesting (energy + harvesting)

Distribution by Scientific Domains

Selected Abstracts

Energy Harvesting with Single-Ion-Selective Nanopores: A Concentration-Gradient-Driven Nanofluidic Power Source

Wei Guo
Abstract Inspired by biological systems that have the inherent skill to generate considerable bioelectricity from the salt content in fluids with highly selective ion channels and pumps on cell membranes, herein, a fully abiotic single-pore nanofluidic energy-harvesting system that efficiently converts Gibbs free energy in the form of a salinity gradient into electricity is demonstrated. The maximum power output with the individual nanopore approaches ,26,pW. By exploiting parallelization, the estimated power density can be enhanced by one to three orders over previous ion-exchange membranes. A theoretical description is proposed to explain the power generation with the salinity-gradient-driven nanofluidic system. Calculation results suggest that the electric-power generation and its efficiency can be further optimized by enhancing the surface-charge density (up to 100,mC m,2) and adopting the appropriate nanopore size (between 10 and 50,nm). This facile and cost-efficient energy-harvesting system has the potential to power biomedical tiny devices or construct future clean-energy recovery plants. [source]

Energy Harvesting Using Piezoelectric Nanowires,A Correspondence on "Energy Harvesting Using Nanowires?"

by Alexe et al.
A response to the questions raised by Alexe et al. concerning nanowire-based nanogenerators is presented. Evidence is given about the existence and detection of a piezoelectric potential in ZnO nanowires. The role played by the piezoelectric potential is to overcome the threshold voltage at the Pt,ZnO junction, while the observed output signal of ,10,mV is the difference in Fermi levels between the two electrodes. The measurement system used by Alexe et al. is questioned, as is their model. [source]

Singlet Excitation Energy Harvesting and Triplet Emission in the Self-Assembled System Poly{1,4-phenylene-[9,9-bis (4-phenoxy-butylsulfonate)]fluorene-2,7-diyl} copolymer/tris(bipyridyl)ruthenium(II)in Aqueous Solution

ADVANCED MATERIALS, Issue 10-11 2009
Hugh D. Burrows
Tris(bipyridyl)ruthenium(II) self-assembles with the oppositely charged conjugated-polyelectrolyte poly{1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2, 7-diyl} in aqueous solution in the presence of the nonionic surfactant C12E5. Rapid energy transfer is observed from the singlet state of the polyelectrolyte to the metal complex, leading to emission from the triplet state of the ruthenium complex. [source]

High Breakdown Field Dielectric Elastomer Actuators Using Encapsulated Polyaniline as High Dielectric Constant Filler

Martin Molberg
Abstract A novel method allowing rapid production of reliable composites with increased dielectric constant and high dielectric strength for dielectric elastomer actuators (DEA) is reported. The promising approach using composites of conductive particles and insulating polymers generally suffers from low breakdown fields when applied to DEA devices. The present publication shows how to overcome this deficiency by using conductive polyaniline (PANI) particles encapsulated into an insulating polymer shell prior to dispersion. PANI particles are encapsulated using miniemulsion polymerization (MP) of divinylbenzene (DVB). The encapsulation process is scaled up to approximately 20 g particles per batch. The resulting particles are used as high dielectric constant (,,) fillers. Composites in a polydimethylsiloxane (PDMS) matrix are prepared and the resulting films characterized by dielectric spectroscopy and tensile tests, and evaluated in electromechanical actuators. The composite films show a more than threefold increase in ,,, breakdown field strengths above 50 V ,m,1, and increased strain at break. These novel materials allow tuning the actuation strain or stress output and have potential as materials for energy harvesting. [source]

Magnetic Field-Induced Phase Transformation in NiMnCoIn Magnetic Shape-Memory Alloys,A New Actuation Mechanism with Large Work Output

Haluk E. Karaca
Abstract Magnetic shape memory alloys (MSMAs) have recently been developed into a new class of functional materials that are capable of magnetic-field-induced actuation, mechanical sensing, magnetic refrigeration, and energy harvesting. In the present work, the magnetic &!hyphen;field-induced martensitic phase transformation (FIPT) in Ni45Mn36.5Co5In13.5 MSMA single crystals is characterized as a new actuation mechanism with potential to result in ultra-high actuation work outputs. The effects of the applied magnetic field on the transformation temperatures, magnetization, and superelastic response are investigated. The magnetic work output of NiMnCoIn alloys is determined to be more than 1,MJ m,3 per Tesla, which is one order of magnitude higher than that of the most well-known MSMAs, i.e., NiMnGa alloys. In addition, the work output of NiMnCoIn alloys is orientation independent, potentially surpassing the need for single crystals, and not limited by a saturation magnetic field, as opposed to NiMnGa MSMAs. Experimental and theoretical transformation strains and magnetostress levels are determined as a function of crystal orientation. It is found that [111]-oriented crystals can demonstrate a magnetostress level of 140,MPa T,1 with 1.2% axial strain under compression. These field-induced stress and strain levels are significantly higher than those from existing piezoelectric and magnetostrictive actuators. A thermodynamical framework is introduced to comprehend the magnetic energy contributions during FIPT. The present work reveals that the magnetic FIPT mechanism is promising for magnetic actuation applications and provides new opportunities for applications requiring high actuation work-outputs with relatively large actuation frequencies. One potential issue is the requirement for relatively high critical magnetic fields and field intervals (1.5,3,T) for the onset of FIPT and for reversible FIPT, respectively. [source]

Dendritic macromolecules at the interface of nanoscience and nanotechnology

Jean M.J. Fréchet
Abstract As a result of their unique architecture and structural as well as functional versatility, dendrimers have generated considerable interest in numerous areas of the physical sciences, engineering, as well as the biological sciences. Both their size - in the 1-10 nm range - and their globular shape resemble those of many proteins suggesting a host of biomimetic and nanotechnological applications. This brief highlight describes some of our recent work with nascent applications of dendrimers as unimolecular nanoreactors, as nanoscale antennae for energy harvesting and transduction, and as nanosized carriers for diagnostic or therapeutic applications. While implementation of some of these applications may still be distant, the impatient critic might remember that new markets are not created overnight as demonstrated by the slow commercial acceptance of many promising molecules and technologies with development frequently extending decades after their initial discovery. [source]

Oriented Nanostructures for Energy Conversion and Storage

Jun Liu Dr.
Abstract Recently, the role of nanostructured materials in addressing the challenges in energy and natural resources has attracted wide attention. In particular, oriented nanostructures demonstrate promising properties for energy harvesting, conversion, and storage. In this Review, we highlight the synthesis and application of oriented nanostructures in a few key areas of energy technologies, namely photovoltaics, batteries, supercapacitors, and thermoelectrics. Although the applications differ from field to field, a common fundamental challenge is to improve the generation and transport of electrons and ions. We highlight the role of high surface area to maximize the surface activity and discuss the importance of optimum dimension and architecture, controlled pore channels, and alignment of the nanocrystalline phase to optimize the transport of electrons and ions. Finally, we discuss the challenges in attaining integrated architectures to achieve the desired performance. Brief background information is provided for the relevant technologies, but the emphasis is focused mainly on the nanoscale effects of mostly inorganic-based materials and devices. [source]