Wood has always been one of the most fascinating and most versatile materials, and this is set to continue. Where would we be today without it? Yet for all its versatility, there is one property it has never had - by its very nature, it has never been transparent. Although a number of inventors have managed to give wood a certain transparency, none of these solutions has proven suitable for commercial use. This is where they differ significantly from the development recently unveiled by Professor Lars Berglund and his team from KTH Royal Institute of Technology in Stockholm.

For the first time, the technology developed by the team for transparent wood is also suitable for mass production, enabling the wood to be used for energy-saving buildings, for example. "Transparent wood is an ideal material for solar cells, as it's economical, readily available and renewable," explains Professor Berglund. "This is particularly important when covering large areas with solar cells." The first step toward creating transparent wood is the chemical extraction of lignin, which makes tree cells solid. The wood is then impregnated with a transparent polymer to obtain the familiar stability. At the end of the complete procedure, the wood has an incredible 85 percent translucency level. "Nobody had ever considered the possibility of manufacturing larger transparent structures for use in solar cells and buildings," says Berglund. Now the researchers are working to prepare their invention for mass production and make the wood even more transparent. "We're also planning to work with different types of wood," adds Berglund.

KTH Royal Institute of Technology (114 28 Stockholm, Sweden)
Website: www.kth.se/en