Researchers behind an innovative transparent wood composite have integrated the material with solar cells, potentially resulting in a cheaper and more robust form of solar photovoltaic panel.
Sweden’s KTH Royal Institute of Technology created 1mm-thick sheets of 85% transparent wood composite by stripping the lignin from balsa wood and replacing it with a plastic polymer. The sheets produced in its laboratory are up to 15cm square.
Working prototypes integrating solar cells into the sheets have been produced, in collaboration with the Institute’s Solar Cell Group, and are currently being tested to assess performance.
Using wood instead of chemically treated glass could make solar PV technology much cheaper in the long term, the Swedish scientists claim.
"The most promising application we are working on is solar cells, we have made devices integrating solar cells into transparent wood composite and are now measuring performance to see if we can make it an interesting proposition."
Lars Berglund, lead researcher, KTH
Lars Berglund, lead researcher at KTH, commented: “The most promising application we are working on is solar cells, we have made devices integrating solar cells into transparent wood composite and are now measuring performance to see if we can make it an interesting proposition.
“In commercialising transparent wood composite technology, it is easier to initially focus on high technology applications like this that are less cost sensitive with sufficient value to justify the cost of modifying the wood.”
The transparent wood is manufactured using a process similar to chemical pulping, removing strips of lignin, a form of cellulose that gives wood its brownish color, from wood veneer pieces, then infusing the wood with plastic polymer.
It is roughly twice as strong as plexiglass, and cheaper and more sustainable to produce than glass, say the researchers, who are also examining its use in structural applications such as thick transparent walls in buildings and shatter-proof load-bearing windows.
In addition, they are working to reduce the opaqueness of samples so the wood component has the same level of transparency as the plastic polymer.
Berglund said: “We are trying to improve levels of transparency because that will be critical to the different types of applications we want to develop. A key challenge is matching the optical properties of cellulose with those of the plastic polymer. You can’t tell how well it will work until you experiment, our first efforts were quite encouraging so we kept on going.”
Although the environmental sustainability of manufacture has not yet been calculated, Berglund says it is significantly less carbon intensive than producing glass, which needs to be heated to over 1,500 deg C.
