Transparent Wood Material Developed for Buildings, Solar Cells

Researchers at Stockholm's KTH Royal Institute of Technology have developed a transparent wood material that is suitable for mass production of windows and solar panels.

The optically transparent wood is a type of veneer in which the lignin, a component of the cell walls, is removed chemically. After the lignin has been removed, the wood becomes white.

A transparent effect is then achieved with "some nanoscale tailoring," says Lars Berglund, a professor at Wallenberg Wood Science Center at KTH. According to Berglund, the white porous veneer substrate is impregnated with a transparent polymer and the optical properties of the two are then matched.

Berglund says that while optically transparent wood has been developed for microscopic samples in the study of wood anatomy, the KTH project introduces a way to use the material on a large scale. "No one has previously considered the possibility of creating larger transparent structures for use as solar cells and in buildings," he says.

According to Berglund, transparent wood is a good material for solar cells because it is a low-cost, readily available and renewable resource. "This becomes particularly important in covering large surfaces with solar cells," he adds.

Berglund says transparent wood panels can also be used for windows and semitransparent facades in instances when both light and privacy are desired.

Research will focus next on enhancing the transparency of the material and scaling up the manufacturing process. "We also intend to work further with different types of wood," he adds.

"Wood is by far the most used bio-based material in buildings," Berglund continues. "It's attractive that the material comes from renewable sources. It also offers excellent mechanical properties, including strength, toughness, low density and low thermal conductivity."