Washington, Sep 22 (IANS) A new "smart" window can automatically darken to save air conditioning costs on hot days and return to crystal clarity to capture the sun's heat in winters.


It also eliminates drawbacks that smart windows currently available suffer from - potentially toxic substances, high costs and rapid deterioration.

Jeong Ho Cho, formerly materials scientist at the University of Minnesota, and study authors Ho Sun Lim, Jooyong Kim and Chang Hwan Lee developed this new window with the help of a polymer, the journal Nano reports.

The polymer, so-called counterions and a solvent such as methanol was low cost and a less harsh way to make a stable, robust smart window, according to a university statement.

It has the added advantage of being extremely tunable - quickly and easily switching from 100 percent opaque to almost completely clear in seconds.

"To our knowledge, such extreme optical switching behaviour is unprecedented among established smart windows," the authors stated.

"This type of light control system may provide a new option for saving on heating, cooling and lighting costs through managing the light transmitted into the interior of a house," they said.