Researchers from the Institute for Research in Electronics and Applied Physics, University of Maryland designed smart windows that can harness solar energy as well as adjust to either allow or block light using a switch. The solar smart window not only uses the solar energy to power itself up but can also store energy for powering other devices.
The technology uses a polymer matrix imbued with microdroplets of liquid crystals and an amorphous silicon layer like those in solar cells. These are then sandwiched in between glass panes.
When turned off, the liquid crystals disperse light, making the window opaque as the silicon absorbs solar energy—which it will later use for powering itself up. These liquid crystals adjust when turned on, allowing light to pass through.
The ingenious thing is that even when turned on, the window remains opaque when viewed from certain angles. This means that some light is still absorbed and the window is partially charging while simultaneously allowing light in, maximizing the window’s energy absorption and efficiency.
Watch this video to see how the technology works:
The ability to switch the windows on and off ensures that users maintain control over the windows not just for temperature management but also for privacy purposes, as opposed to existing solar-powered smart windows which automatically decide when to block out light, and when to allow visibility. This eliminates the need to employ the use of curtains or blinds.
Apart from this, adaptation of its energy efficiency mechanism could revolutionize many optoelectronic devices: “the ability to electrically control transparency and scattering of light is important for many optoelectronic devices; however, such versatility usually comes with additional unwanted optical absorption and power loss.”
The new solar smart windows also require very little energy for self-powering: as little as 13 nanometers of amorphous silicon. The NASA-funded study has been published in ACS Photonics.