NREL scientists are developing windows that can generate electricity and provide their own shade

Glass that darkens when exposed to sunlight is nothing new, but scientists at the National Renewable Energy Laboratory in Golden have developed a product that not only darkens but can generate electricity.

Scientist Lance Wheeler was experimenting using gas molecules that move through an absorbent layer of glass that acts as a solar power cell when he placed the glass on a hot plate to dry after treating it with methylamine gas.

As the glass heated, it turned brown. When he removed it from the heat source, it became transparent.

“He was just making a solar cell, but he didn’t expect it to act the way it did. That was really a ‘What was that?’ moment,” said Robert Tenent, NREL senior scientist for window technology who worked with Wheeler. He played with it for a bit and came to us and said,