"Transparent wood is a good material for solar cells, since it's a low-cost, readily available and renewable resource," said lead researcher Lars Berglund. "This becomes particularly important in covering large surfaces with solar cells."
The transparent wood was created by first stripping all the lignin from the material. That makes the wood white, the researchers explained, but doesn't make it see-through.
But by embedding the white wood with a transparent polymer known as prepolymerised methyl methacrylate (PMMA), the team was able to alter its refractive index in order to achieve light transmittance of up to 85% - while still retaining its wooden structure.
While wood-based materials have been made transparent before, it's always been on the very-small scale, for example, to be used in wood-based computer chips. But this new light-weight material could have bigger applications. "No one has previously considered the possibility of creating larger transparent structures for use as solar cells and in buildings," said Berglund.
The team is now working on scaling up the manufacturing process to make sure it's as cheap and easy as possible, and will also experiment with different types of wood to see if they can improve transparency. "It's attractive that the material comes from renewable sources," said Berglund. "It also offers excellent mechanical properties, including strength, toughness, low density and low thermal conductivity."