The windows are ultra-resistant to water, thanks to pencil-like microscopic structures in the glass.
Water simply rolls off the panes in spherical droplets, picking up dirt, dust, and other contaminants and carrying them away.
A super-thin coating of vanadium dioxide also prevents heat loss from the windows in cold periods. In hot weather, it also prevents infra-red radiation from the sun entering the building and raising the temperature.
Ioannis Papakonstantinou, who leads the University College London team, said: “This is the first time that a nano-structure has been combined with a thermo-chromic coating.
“The bio-inspired nanostructure amplifies the thermo-chromics properties of the coating and the net result is a self-cleaning, highly performing smart window. It’s estimated that, because of the obvious difficulties involved, the cost of cleaning a skyscraper’s windows in its first five years is the same as the original cost of installing them.
“Our glass could drastically cut this expenditure, quite apart from the appeal of lower energy bills and improved occupant productivity thanks to less glare.”
The first smart windows could reach the market in three to five years.