Plastic sheet becomes solar cell with spray-on coating

A “spray-on” coating method has been successfully used to generate electricity on flexible plastics. Alternative and renewable energy

research company New Energy Technologies Inc. (Columbia, MD) has extended its patent-pending SolarWindow technology to plastics, after launching it last year for glass windows.

The company believes that commercially developed electricity-generating flexible plastic could be deployed in the field as a tinted window film that remains see-through while generating electrical power. New Energy Technologies said in a release that temperature-specific, pressure sensitive, and expensive process methods for applying coatings to plastic surfaces had traditionally handicapped the prospect of creating see-through flexible plastic that could generate electricity.New Energy Technologies SolarWindow

New Energy says that by spraying its electricity-generating coatings onto a flexible, lightweight lab-scale plastic, like polyethylene terephthalate (PET) at room temperature and low pressure, the process can result in reduced manufacturing costs. In the development of the first working PET prototype, the researchers also overcame surface-preparation issues, which are considered vital to achieving maximum strength of the coating’s bond to the surface, as well as for optimizing product durability and lifespan.

The solar coatings are less than 1/10th the thickness of so-called “thin films”, according to New Energy, and utilize what it calls the world’s smallest functional solar cells. New Energy reports creating a solar array with 20 miniature cells interconnected in series, using photolithography to isolate the individual cells and output contacts of the array, and thermal-vacuum deposition to make the array’s series connections. That total device covered an area of 2.2 cm2, with 1 mm2 for a single cell.

The researchers noted that the sheet was able to maintain flexibility as well as the ability to generate electricity on the plastic’s surface and distribute that energy to the circuit. New Energy has filed 10 new patent claims for its SolarWindow technology.


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