José Manuel NievesSEGUIR Updated: Save Send news by mail electrónicoTu name *

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Some day, is the subtle border between the light and the shadow will be able to generate energy for all. The idea, developed by a team of researchers from the National University of Singapore, already has been embodied in a device, called the SEC (“Shadow-effect Energy Generator” or Generator of Energy for shadow Effect), which generates an electric current capable of powering small electronic devices. “We can collect energy at any place of the Earth, and not only in open spaces,” says Swee Ching Tan, co-author of an article recently appeared in “Energy & Environmental Science”.

“The shadows are ever-present -continues As – and often we don’t even look at them. In photovoltaic applications, or optoelectronics conventional, where it is used a source of constant light to power devices, the presence of shadows is not desirable, as it degrades your performance. But in this work n I focus on the contrast of illumination caused by the shadows as a source indirect energy. This contrast induces a voltage difference between the shadows and the sections lit, resulting in an electric current. This novel concept of energy harvesting is unprecedented”.

take Advantage of a contrasting ubiquitous

Any electronic device, from cell phones to smart watches, you need to have a source of power efficient and continuous. And given that people use these devices everywhere, both indoors and outdoors, Tan and his team have devised a way that they can utilize the ambient light to recharge, what it would take to overcome one of its greatest limitations. Both inside a room and outdoors, in fact, there are lit areas next to areas in shadow. The idea of the scientists is to take advantage of this contrast is omnipresent to generate energy required for these devices to function.

On the outside, and provided there’s ample light, the solar cells already play that role, but his efficiency when collecting energy decrease significantly in shadow areas, and is void almost completely in the interior spaces, in which shadows are everywhere .

To address this technological challenge, the researchers developed a Power Generator for shadow Effect (S) low cost and easy to fabricate to carry out two tasks: converting the contrast between light areas and shadow areas in electricity, and operate at the same time as a proximity sensor feedback to control the objects that pass near.

Cells aligned in a film

The device consists of a set of cells S that are aligned in a film of plastic flexible and transparent. is Each cell S is a thin gold film deposited on a silicon wafer. The SEC can be manufactured at a cost much lower than that of silicon solar cells conventional. After that, the researchers carried out experiments to test the performance of the SEC, both to generate electricity as function as a proximity sensor self-powered.

“When all the cell S is illuminated or in shadow,” explains Andrew Wee, co-director of the research – the amount of electricity generated is very low or zero. But when a part of the cell S is lit (while the other remains in shadow) is detected and an electrical output significant. We also discovered that the area of optimal surface for the generation of electricity is when half of each S is illuminated and the other half in the shade, as this provides an area sufficient for the generation and collection of charging, respectively.”

Best with part shade under light

According to the results of the experiments in the laboratory, the SEC of four cells tested by the team turned out to be two times more efficient, with shadows shifting, that the solar cells business. The energy collected by the SEC in the presence of shadows that are created in indoor lighting conditions, in fact, it was enough to power a digital clock (i.e., 1.2 volts).

in Addition, the team also showed that the SEC can serve as a sensor self-powered for monitoring objects in motion . When an object passes near the SEC, in effect, casts a shadow flashing on the device and activates the sensor to register the presence and movement of the object. The own shadow that creates the object, then, provides the SEC with sufficient energy to be activated and working.

The researchers took four months to conceive, develop and refine the performance of the device. In the next phase of research, experiment with different materials to gold, to further reduce the cost of production of the SEC.

The scientists also study the development of sensors self-powered for all types of uses, as well as SEC portable that could, for example, connect to the clothes to be picking up energy during our daily activities. Finally, scientists believe that the panels S you could have a bright future for the efficient collection of energy in the interior lighting.