MARINE sponges are humble creatures, but some of them have a special talent. They can harvest silicon from seawater, and use it to build the spiky filaments that cover their body. Now this process has inspired the development of a cheap, low-energy method of manufacturing solar cells.
The usual way of making solar cells involves techniques such as vapour deposition, in which chemicals are laid down on an inert surface, or “substrate”, to create a layer of crystalline semiconductor that produces an electric current when light strikes it. This is done at high temperature and very low pressure, making it…
