Wood can be turned into window panes.
Now, a US-based startup has developed a transparent coating that allows glass windows to generate electricity by harvesting sunlight.
The patented, nanometre-thin coating is applied to new windows using physical vapour deposition and, like colour pigments, consists of non-hazardous, naturally-occurring materials.
Delicate, hidden wires ensure that only ultraviolet and infrared rays are converted into energy. All other light illuminates interior rooms.
A 150×90 centimetre window can generate up to 200 watt hours per day. Enough to charge 13 cell phones or power Smart Home applications or a security system.
Others are working on solutions using food waste or for greenhouses.
These solar cells, meanwhile, are spiced up by chillis.
