Optoelectronics

A good example of the kind of technologies that result from NREL's work in optoelectronic technologies is in the area of electrochromic materials. These are materials, already used as a way to reduce glare in the rearview mirror of a car or truck, that undergo reversible changes in their optical absorption properties when small ions are inserted electrochemically into their crystal structures. When thin films made of these materials are applied in several coatings to glass, for example, they can be used to "intelligently" modulate the transmission of light through the glass, providing solar heat gain when needed or screening it out otherwise. Such "smart" windows are automatic energy savers, literally darkening when the sun shines, but lightening on cloudy or overcast days.

Combining solar cells with an electrochromic film results in a self-powered window, which still has all the intelligence of the smart window. With an estimated 20 billion square feet of window area in the United States, it's clear that our national energy consumption could be reduced by several percent by deploying highly efficient, smart windows.

Other technologies that are topics of research for our team are fiber-optic-based hydrogen sensors, supercapacitor materials, and battery materials. These have a theme in common with the electrochromic windows in that the intercalation of small ions into the host lattice causes effects that are useful in each of these technologies. The hydrogen sensor will provide an inexpensive safety sensor to support the hydrogen infrastructure of the future. Work in supercapacitor and battery materials should result in significant improvements that will be extremely valuable for the application of secondary batteries in transportation technologies.

For staff profiles, publications, and contact information see Optoelectronics Research staff.