A see-through technology generates electricity on glass and flexible plastics surfaces

A see-through technology capable of generating electricity on glass and flexible plastics has been unveiled. The first-of-its kind SolarWindow™ technology, which enables see-through windows to generate electricity by ‘spraying’ their glass surfaces with electricity-generating coatings, has been developed by New Energy Technologies. The coatings make use of the world’s smallest functional organic solar cells, which measure less than ¼ the size of a grain of rice, and have been shown to successfully produce electricity in a published study in the Journal of Renewable and Sustainable Energy of the American Institute of Physics. The coating does not require expensive high-temperature or high-vacuum production methods, but can be sprayed on to glass at room temperature. They generate electricity from both natural and artificial light sources, outperforming today’s commercial solar and thin-film technologies by as much as 10-fold; and measure less than 1/10th the thickness of ‘thin’ films (only 1/1000th the thickness of human hair).

New Energy’s organic solar array has:

The same desirable electrical properties as silicon, yet boasts a considerably better capacity to ‘optically absorb’ photons from light to generate electricity, and achieves transparency through the innovative use of conducting polymers;
Superior optical absorption properties inherent to it’s ultra-small solar cells, enabling development of an ultra-thin film, only 1/1000th the thickness of a human hair, or 1/10th of a micrometer; and
A key advantage over conventional thin films which are exponentially thicker, measuring several micrometers thick, thus inhibiting transparency.

SolarWindow™ electricity-generating coating works with natural (sun) and artificial (light bulb) light. Under normal office lighting conditions, without the benefit of outside natural light from windows, New Energy’s ultra-small solar cells produced: Almost 2-fold greater output power density than Monocrystalline silicon, an established commercial solar cell material; more than 8-fold greater output power density than copper-indium-selenide, known for its high optical absorption coefficients and versatile optical and electrical characteristics; and more than 10-fold greater output power density than flexible thin-film amorphous-silicon, a popular ‘second-generation’ solar thin-film material. While the majority of today's solar cells can only be installed where direct sunlight is available, New Energy's cells could be installed close to any source of visible light.

These electricity-generating coatings are ultra-thin and inherently lightweight and flexible, which potentially allows unique applications for moving and non-planar surfaces such as aircraft components, flight suits, and helmets and visors. These novel spray-on techniques have been pioneered, advanced, and unveiled in operating prototypes by scientists who initiated early research efforts with New Energy Technologies under a Sponsored Research Agreement at the University of South Florida (USF). The Company’s SolarWindow™ technology has since progressed significantly beyond early research, and is now in advanced product development. Aircraft windows and fuselage surfaces, and related components; and pilot flight suits, helmets and visors are among target surfaces included in New Energy’s latest inventions to make use of the Company’s electricity-generating SolarWindow™ coatings. The production of electricity on such surfaces and materials is possible when researchers lightly tint their surfaces with New Energy’s flexible organic, electricity-generating coatings. The result is aesthetically pleasing see-through surfaces, which can have uniquely tailored properties, that generate electricity. Researchers envision applying SolarWindow™ coatings to pilot safety equipment, thus providing much-needed ultra-lightweight emergency power to downed pilots. Researchers further anticipate that supplementary power production from SolarWindow™ coatings could reduce the size and weight of ancillary power systems aboard today’s aircraft, potentially improving fuel consumption while increasing usable aircraft space.

The technology makes use of ultra-small organic solar cells, which:

Allow for the fabrication of transparent solar arrays on a broad range of substrate materials such as glass, plastic, and even paper;
Are made of natural polymers which can be dissolved into liquid for easy application that does not require expensive and complicated high-temperature or high-vacuum production techniques common to other solar coatings; and
Organic solar cells can be manufactured in a variety of ways, including screen printing, ink-jet printing and spraying.