Quantum dot solar window with 3.6% efficiency

UbiQD, a U.S. manufacturer of luminescent glass panels, has deployed its quantum dot-tinted glass luminescent solar concentrator technology on several windows at a Holiday Inn Express hotel in Los Alamos, New Mexico, where the company is based.

“These building pilot installations represent the first real-world tests for UbiQD, and some of the earliest and largest known luminescent concentrator window installations in the world,” the manufacturer said. “The trials aim to validate the importance of parameters like window orientation, time of day, seasonality, temperature, and manufacturing and installation methods.”

It developed the technology with the support of the U.S. Department of Energy's Los Alamos National Laboratory, the Massachusetts Institute of Technology, the University of Washington, and Western Washington University.

The 3.6%-efficient solar window is made via a low-cost manufacturing process with laminated glass and luminescent solar concentrators (LSCs), based on copper indium sulfide and zinc sulfide (CuInS2/ZnS) quantum dots (QDs). The quantum dots are provided by U.S. nanotech company Nanosys and are embedded in a polymer placed in the fluorophore interlayer of the laminated glass.

The QD-tinted glass absorbs sunlight and the glow from the QDs gets trapped in the glass by internal reflection. Glow light is then guided to the window edges, where solar cells are placed in series. These cells form a PV system that can reach a power conversion efficiency of up to 3.6%.

The type of quantum dots used to create the laminated interlayer determines the color of the window.

“We can access nearly the entire color spectrum range with quantum dots, and so there is the customer option to create a really beautiful thing that makes a building pop in a fun way while also creating an impact,” UbiQD CEO Hunter McDaniel said. “The customer can also choose a more normal neutral color tint with our near-infrared dots, and we’ve installed two versions of that as well.”

The manufacturer said its solar concentrator tech is a drop-in solution that can be easily adopted in conventional processes to fabricate windows. It also claims the solar windows have a five-year payback time.

The company recently secured $7 million of venture financing to support the commercial deployment of the windows.

“UbiQD intends to accelerate the deployment of its quantum dot window technology in 2022,” the company said. “Additional window projects are planned in New Mexico, Colorado and Washington state.”