'Invisible wires' for transporting electricity

New Energy Technologies, Inc and NREL scientists collaboratively developing New Energy's SolarWindow(TM) technology - capable of generating electricity on see-through glass - have successfully collected and transported electricity using a virtually 'invisible' conductive wiring system developed for SolarWindow(TM). The ability to transport electricity on glass windows while remaining see-through is especially important to the eventual deployment of an aesthetically pleasing commercial product.

Currently under ongoing development, the conductive system's ultra-fine grid-like pattern is deposited on to SolarWindow(TM) and is rendered virtually invisible when viewing objects through New Energy's electricity-generating glass. Researchers anticipate that a fully functional system could help transport the electricity generated on glass surfaces, improving power, efficiency, and overall performance of the SolarWindow(TM).

This announcement follows last month's breakthrough when New Energy Technologies and NREL scientists successfully fabricated the largest-area organic photovoltaic (OPV) module produced at the United States Department of Energy's

National Renewable Energy Laboratory (NREL). The scientists fabricated a large area working module, more than 14-times larger than previous OPV devices fabricated at NREL.

"It's very exciting that we've not only achieved an important milestone with respect to the size of our SolarWindow(TM), but we are now able to confidently tackle two of the most important factors to eventual commercialization - the structure and transparency of the wiring system which transports the electricity generated on see-through glass, and overall performance," explained Mr. John A. Conklin, President and CEO of New Energy Technologies, Inc.

The prospect of generating electricity on SolarWindow(TM) is made possible when researchers creatively layer and arrange unique, ultra-small see-through solar cells on to glass. Each of these cells are arranged in a network and interconnected by way of the 'invisible' grid-like wiring system. Until now, such systems used in early prototypes were relatively thick and bulky, and applied to glass in ways that obstructed light, prevented the absorbance of light energy necessary to produce electricity, and significantly reduced transparency.

The 'invisible' wiring system is important for allowing more efficient collection and transport of electrons, both important for improving circuit current and overall efficiency. The system helps mitigate electrical 'road-blocks,' which restrict the flow of electrons with regions of high resistance, by creating a kind of low-resistance 'highway' for electron transport; without the benefit of a conductive grid system, resistive losses can significantly reduce power production. A fully functional and optimized system could improve the reliability of SolarWindow(TM) by providing a stable network of connections among each of the interconnected solar cells on the see-through glass.

Scientists demonstrated numerous features of the SolarWindow(TM), including its ability to remain see-through while generating electricity. Both natural and artificial light were used in demonstrations to generate electricity. At the demonstration event, scientists powered lights on a scale-model house by exposing the window to artificial light from fluorescent lamps, mimicking lighting typically installed inside offices. According to the scientists, in artificial light SolarWindow(TM) technology outperforms today's commercial solar and thin-films by as much as 10-fold under low-intensity irradiance.

Researchers then repeatedly opened and closed the boardroom's window shades, successfully powering LED lights each time SolarWindow(TM) was exposed to natural light. This demonstration mimicked outdoor exposure such as sunlight on the exterior face of commercial buildings. Importantly, scientists also demonstrated SolarWindow's ability to generate 'voltage' and 'current' necessary to power lighting and mechanical devices and appliances. In addition to lighting, scientists successfully powered the mechanical rotor blades of a small helicopter using only a single, small-scale SolarWindow(TM) prototype during their public demonstration.