Combining two types of electricity generation into one textile paves the way for developing garments that could provide their own source of energy to power devices such as smart phones or global positioning systems.

“This hybrid power textile presents a novel solution to charging devices in the field from something as simple as the wind blowing on a sunny day,” said Zhong Lin Wang, a Regents professor in the Georgia Tech School of Materials Science and Engineering.

The research was reported September 12 in the Nature Energy.

To make the fabric, Wang’s team used a commercial textile machine to weave together solar cells constructed from lightweight polymer fibers with fiber-based triboelectric nanogenerators.

Triboelectric nanogenerators use a combination of the triboelectric effect and electrostatic induction to generate small amount of electrical power from mechanical motion such as rotation, sliding or vibration.

Wang envisions that the new fabric, which is 320 micrometers thick woven together with strands of wool, could be integrated into tents, curtains or wearable garments.

“The fabric is highly flexible, breathable, light weight and adaptable to a range of uses,” Wang said.

Fiber-based triboelectric nanogenerators capture the energy created when certain materials become electrically charged after they come into moving contact with a different material. For the sunlight-harvesting part of the fabric, Wang’s team used photoanodes made in a wire-shaped fashion that could be woven together with other fibers.

“The backbone of the textile is made of commonly-used polymer materials that are inexpensive to make and environmentally friendly,” Wang said. “The electrodes are also made through a low cost process, which makes it possible to use large-scale manufacturing.”

In one of their experiments, Wang’s team used a fabric only about the size of a sheet of office paper and attached it to rod like a small colorful flag. Rolling down the windows in a car and letting the flag blow in the wind, the researchers were able to generate significant power from a moving car on a cloudy day. The researchers also measured the output by a 4 by 5 centimeter piece, which charged up a 2 mF commercial capacitor to 2 volts in one minute under sunlight and movement.

“That indicates it has a decent capability of working even in a harsh environment,” Wang said.

While early tests indicate the fabric can withstand repeated and rigorous use, researches will be looking into its long-term durability. Next steps also include further optimizing the fabric for industrial uses, including developing proper encapsulation to protect the electrical components from rain and moisture.

Story Source:

The above post is reprinted from materials provided by Georgia Institute of Technology. Note: Content may be edited for style and length.

Journal Reference:

1. Jun Chen, Yi Huang, Nannan Zhang, Haiyang Zou, Ruiyuan Liu, Changyuan Tao, Xing Fan, Zhong Lin Wang. Micro-cable structured textile for simultaneously harvesting solar and mechanical energy. Nature Energy, 2016; 1: 16138 DOI: 10.1038/nenergy.2016.138

Scientists have controlled electrons by packing them so tightly that they start to display quantum effects, using an extension of the technology currently used to make computer processors. The technique, reported in the journal Nature Communications, has uncovered properties of quantum matter that could pave a way to new quantum technologies.

The ability to control electrons in this way may lay the groundwork for many technological advances, including quantum computers that can solve problems fundamentally intractable by modern electronics. Before such technologies become practical however, researchers need to better understand quantum, or wave-like, particles, and more importantly, the interactions between them.

Squeezing electrons into a one-dimensional ‘quantum wire’ amplifies their quantum nature to the point that it can be seen, by measuring at what energy and wavelength (or momentum) electrons can be injected into the wire.

“Think of a crowded train carriage, with people standing tightly packed all the way down the centre of the carriage,” said Professor Christopher Ford of the University of Cambridge’s Cavendish Laboratory, one of the paper’s co-authors. “If someone tries to get in a door, they have to push the people closest to them along a bit to make room. In turn, those people push slightly on their neighbours, and so on. A wave of compression passes down the carriage, at some speed related to how people interact with their neighbours, and that speed probably depends on how hard they were shoved by the person getting on the train. By measuring this speed, one could learn about the interactions.”

“The same is true for electrons in a quantum wire — they repel each other and cannot get past, so if one electron enters or leaves, it excites a compressive wave like the people in the train,” said the paper’s first author Dr Maria Moreno, also from the Cavendish Laboratory.

However, electrons have another characteristic, their angular momentum or ‘spin’, which also interacts with their neighbours. Spin can also set off a wave carrying energy along the wire, and this spin wave travels at a different speed to the charge wave. Measuring the wavelength of these waves as the energy is varied is called tunnelling spectroscopy. The separate spin and charge waves were detected experimentally by researchers from Harvard and Cambridge Universities.

Now, in the paper published in Nature Communications, the Cambridge researchers have gone one stage further, to test the latest predictions of what should happen at high energies, where the original theory breaks down.

A flurry of theoretical activity in the past decade has led to new predictions of other ways of exciting waves among the electrons — it’s as if the person entering the train pushes so hard some people fall over and knock into others much further down the carriage. These new ‘modes’ are weaker than the spin and charge waves and so are harder to detect.

The collaborators of the Cambridge researchers from the University of Birmingham predicted that there would be a hierarchy of modes corresponding to the variety of ways in which the interactions can affect the quantum-mechanical particles, and the weaker modes should be strongest in very short wires.

To make a set of such short wires, the Cambridge group set about devising a way of making contact to a set of 6000 narrow strips of metal that are used to create the quantum wires from the semiconducting material gallium arsenide (GaAs). This required an extra layer of metal in the shape of bridges between the strips.

By varying the magnetic field and voltage, the tunnelling from the wires to an adjacent sheet of electrons could be mapped out, and this revealed evidence for the extra curves predicted, where it can be seen as an upside-down replica of the spin curve.

These results will now be applied to better understand and control the behaviour of electrons in the building blocks of a quantum computer.

Story Source:

The above post is reprinted from materials provided byUniversity of Cambridge. Note: Content may be edited for style and length.

Journal Reference:

1. M Moreno, C. J. B. Ford, Y. Jin, J. P. Griffiths, I. Farrer, G. A. C. Jones, D. A. Ritchie, O. Tsyplyatyev, A. J. Schofield.Nonlinear spectra of spinons and holons in short GaAs quantum wires. Nature Communications, 2016; 7: 12784 DOI: 10.1038/ncomms12784