The trend toward integrating solar into homes and buildings seems to be taking off. First Tesla CEO Elon Musk unveiled his rooftop solar shingles that are invisible when viewed from the street. Now, researchers at the University of Minnesota and University of Milano-Bicocca have developed technology that could usher in a future with photovoltaic windows harvesting renewable energy from the sun. The research, published Tuesday in the journal Nature Photonics, demonstrates that high-tech silicon nanoparticles embedded into luminescent solar concentrators (LSCs) can make the performance of solar windows more efficient, comparable to flat solar concentrators.

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“In our lab, we ‘trick’ nature by shirking the dimension of silicon crystals to a few nanometers, that is about one ten-thousandths of the diameter of human hair,” said University of Minnesota mechanical engineering professor Uwe Kortshagen, one of the senior authors of the study. “At this size, silicon’s properties change and it becomes an efficient light emitter, with the important property not to re-absorb its own luminescence. This is the key feature that makes silicon nanoparticles ideally suited for LSC applications.”

Related: Revolutionary new solar windows could generate 50 times more power than conventional photovoltaics

Photovoltaic windows could be a game changer in the race to power cities with renewable energy and reduce greenhouse gas emissions causing climate change. Modern glass office towers could be retrofitted with photovoltaic windows that wouldn’t change the aesthetics of the building and yet would be able to meet the structure’s electricity needs. According to the US Department of Energy, turning the windows at One World Trade Center into solar collectors could power more than 350 apartments.

The researchers say that silicon nanoparticles could make solar windows commercially viable for the building-integrated photovoltaic market. The silicon nanoparticles, which are produced using a plasma reactor and formed into a powder, could realize flexible LSCs that efficiently capture more than five percent of the sun’s energy. One day soon the sun shining on skyscrapers in cities around the world could also be the source of their energy.

+ Highly efficient luminescent solar concentrators based on earth-abundant indirect-bandgap silicon quantum dots


Images via University of Minnesota