A window that can be darkened or lightened electronically.
This is due to the migration of ions. A small voltage applied to
the windows will cause it to darken. The electrochromic layer used is
typically tungsten oxide (WO3)
There are many benefits for electrochromic windows. For instance you
can shade them so to control the amount of daylight, solar heat, gained
through the windows. Attaching the window to a photovoltaic cell can
automatically regulate solar input.
__neg_| Plastic layer |
| | Transparent conducting oxide e- |
| | Electrochromic |/| |
--- | Ion conductor/electrolyte | |
--- | Ion storage A+ |
|__pos_| Transparent conducting oxide |
| Plastic layer |