3M has developed a see-through film that turns ordinary windows into solar panels. It will go on sale next year.
The solar film, on display at the Ceatec electronics conference in Japan, is arrayed in narrow, translucent green strips with clear gaps between and then glued to windows in large patches. A square meter of the film can generate roughly enough electricity to charge an iPhone under peak sunlight, but still allows for high visibility.
The film might cost about half as much as solar panels, but will produce less electricity. It is easier to install and takes up no additional space.
"An average person could go to the store, buy some of this, and then bring it home and install it themselves," said Yasuhiro Aoyagi, a senior manager in the company's construction markets division.
The film blocks or absorbs about 80% of visible light and over 90% of infrared light, so it also acts as a sunshade. Demonstrations showed a difference of 10 degrees Celsius between two sides of a window it was attached to.