Spray-On Nanopolymer Captures Solar Energy

by Charles W. Thurston Latin America Correspondent thurstoncw@rodmanmedia.com

Solar energy is a topic of great inter- est throughout the world, including Latin America. A novel approach to applying organic nanopolymer-based photovoltaic functionality to clear and semi-transparent building windows is being honed by researchers at the U.S. National Renewable Energy Laboratory, in Golden, CO, through second-stage cooperation with the technology originator, New Energy Technologies, of Colombia, MD. While the company has already produced – in cooperation with the University of Florida – a small pane of conductive glass that will power LEDs and small motors, the current goal is a standard-sized glass window that can be coated in commercial manufacturing scale at low cost, without the use of high temperature or pressure common in the industry today.

The organic photovoltaic (OPV) coatings developed by New Energy Technologies are less than one-tenth of the thickness of thin film solar cells, or one-thousandth the thickness of a human hair; the company has filed 11 patents for the processes.

“Our Solar Window technology of ultra-small solar cells can be installed anywhere that direct sunlight or artificial lighting such as fluorescent systems emit visible light,” noted Patrick Thompson, New Energy Technologies’ vice president for business and technology development, in a recent company report. As such, the windows can capture interior light at night, as well as non-solar night light from outside the building. Research is also underway to coat flexible transparent and semi-transparent materials with the OPV element, including plastic and paper.

“In artificial light, SolarWindow technology outperforms today’s commercial solar and thin-films by as much as 10-fold under low-intensity irradiance,” added

John Conklin, president and CEO of New Energy Technologies.

Apart from optimizing the electrical functionality of the product, which is based on alternating layers of “common material” polymers, the NREL researchers hope to devise “high speed and large area roll-to-roll and sheet-to-sheet coating methods required for commercial-scale BIPV and windows,” according to a company statement in March. Officials at New Energy Technologies declined interviews for this story.

“Our proprietary spray application method has proved superior durability against harsh mechanical bending. In contrast, conventional spin-coating methods in the lab resulted in immediate breakdown. Importantly, our method does not require the conventional temperature and pressure sensitive manufacturing methods that add to conventional PV systems’ current high cost,” said Conklin in a Dec.

21, 2012 address to shareholders.

His company is quick to point to the immense U.S. market for OPV windows _ some five million buildings and 80 million residences – as well as the potential savings over traditional window materials: “In December 2010, our power production modeling calculations were validated by Steven Hegedus, Ph.D., a renowned scientist and authority in photovoltaics. His lab confirmed our important estimate that a 40-story glass building fitted with Solar Window could see from $40,000 to $70,000 in savings per year. In comparison, common roof-top (PV) modules only produce $20,000 in savings,” said Conklin.

There are a host of competitors at work in the nanotech OPV market. DuPont, 3M, and several Chinese companies are among a larger number of companies currently producing solar products that are transparent or semi-transparent. CW