Windows: No Longer Just for Letting In the Light

That’s because the new glass panes will offer more than a stunning view of the arid mountains and blues skies of the landscape. They will also double up as solar panels, able to power the company’s lights, laptops and air conditioners.

Several years in the making, Ubiquitous’s energy-generating glass is a neat technological feat. Its power lies in the layers of organic polymers between sheets of glass. Some of them permit all light to pass through while others absorb photons of non-visible infra-red and ultraviolet light. As light enters the window, the flow of electrons between the polymer layers creates an electric current, which is then collected by microscopic wires in the glass.

Instead of electricity being shuttled to different points in a display to light them up, light is generating electricity to be shuttled out of different points in the window.

Right now the windows produce about a third as much electricity from a given amount of sunlight as the typical solar cells used in roof panels, and they’re about half as transparent as ordinary glass.

But those specs are already enough to make the windows a viable product, the company is likely to improve the transparency significantly. As for the lower output of electricity, windows can cover a much greater surface area than a roof, so the sheer number of windows will swamp the electrical production from a rooftop full of higher-efficiency solar panels. You could do both, but you’ll get more from the windows.

The new windows incorporate a layer that combines indium tin oxide with platinum, and a second layer of nickel oxide, with a solution of lithium between them. When a small voltage is applied across the two layers they act as electrodes, producing an electric field that causes lithium ions to move through the solution and cling to the nickel oxide layer.

Though the lithium is transparent in solution, when it coats the nickel oxide it becomes semi-opaque. “You only need a 10 nanometer layer of lithium on the electrode to block most light.

The result is a window that acts as “sunglasses for a building,” as he puts it. What’s more, varying the voltage allows dialing in a particular level of darkening.

If these projects turn out to be commercially successful, windows could be an important part of smart cities that are both convenient and green in another decade or two. That would be a step towards reducing humankind’s carbon footprint to zero