Can鈥檛 decide whether or not to kit out your car with tinted windows? Now you
can have it both ways with windows that tint at the flick of a switch.
Chemists at BASF in Germany made the windows by coating panes of glass with a
thin layer of transparent tungsten oxide. They then added a transparent polymer
coating and a layer of cerium and titanium oxide doped with lithium ions.
Applying a voltage across the window forces lithium ions through the polymer
layer and into the tungsten oxide, turning it dark blue. Reversing the current
switches the windows back to clear.