A new type of nearly invisible solar cells could help everyday glasses generate electricity. This may include car windows and sunroofs, smart glasses, wearables, building facades and home windows.
Scientists at Nanyang Technological University, Singapore, have developed transparent perovskite solar cells that are about 10,000 smaller than a strand of human hair and 50 times thinner than conventional perovskite solar cells. The NTU research team, led by Associate Professor Annalisa Bruno, published the findings in ACS Energy Letters (via TechXplore).
Can solar cells disappear from everyday glass?
These solar cells are very light and have no center, so they can be added to glass without making them look like regular solar panels. This can be useful in cities where roofs are already used for solar, but windows and vertical glass facades remain unused.
Researchers around the world are trying to make solar technology easier to use and more attractive to everyday users. Others are working on colored solar cells that can make the panels look better on homes, while NTU’s approach focuses on making solar cells that almost disappear from the glass. If it works at scale, it could help solve one of solar’s biggest challenges by generating clean energy without asking people to change the way their homes, cars, or appliances look.
NTU says the cells can generate electricity under indirect and diffuse light, making them useful in dense urban buildings with limited sunlight. If scaled successfully, large glass-fronted buildings can generate several hundred megawatt-hours of electricity per year, depending on the shape and usable area of the glass.
What challenges remain before commercial use?
The team made the cells using a process called thermal evaporation, where the material is heated inside a vacuum chamber until it turns into vapor, which then settles as a very thin layer. NTU says this helps create layers even over large areas, avoids toxic solvents, and allows researchers to control how transparent the solar cells are.
The best result came from the 60 nanometer opaque cell, which reached about 12%. Thinner opaque versions achieved about 11% efficiency at 30 nanometers and 7% at 10 nanometers. The 60 nanometer semi-transparent version allowed about 41% of visible light to pass while achieving an efficiency of 7.6%.
In comparison, conventional rooftop solar panels are very efficient, with most commercial home panels converting about 18% to 24% of sunlight into electricity. The transparent NTU cell doesn’t try to beat those panels with raw power. Its advantage is that it can fit into areas where conventional solar panels will not work or are undesirable.
This is still stage research, not a product ready for windows, cars, or wearables. NTU has filed a patent and is talking to companies to validate the manufacturing process. Researchers still need to prove that the cells can remain stable, survive long-term use, and perform well when produced in large quantities.
