LUMINESCENT WOOD PROVIDES LIGHT IN HOMES OF THE FUTURE

Sat 07 November 2020:

The right indoor lighting can help set the mood, from a soft romantic glow to bright, stimulating colours. But some materials used for lighting, such as plastics, are not eco-friendly.

Now, researchers reporting in ACS Nano have developed a bio-based, luminescent, water-resistant wood film that could someday be used as cover panels for lamps, displays and laser devices.

Consumer demand for eco-friendly, renewable materials has driven researchers to investigate wood-based thin films for optical applications. However, many materials developed so far have drawbacks, such as poor mechanical properties, uneven lighting, a lack of water resistance or the need for a petroleum-based polymer matrix. Qiliang Fu, Ingo Burgert and colleagues wanted to develop a luminescent wood film that could overcome these limitations.

The researchers treated balsa wood with a solution to remove lignin and about half of the hemicelluloses, leaving behind a porous scaffold. The team then infused the delignified wood with a solution containing quantum dots –– semiconductor nanoparticles that glow in a particular colour when struck by ultraviolet (UV) light. After compressing and drying, the researchers applied a hydrophobic coating. The result was a dense, water-resistant wood film with excellent mechanical properties.

When exposed to UV light on the outside, a luminescent wood panel (right) lights up an indoor space (as seen through “windows;” red arrows), whereas a non-luminescent panel (left) does not. Image credit: Adapted from ACS Nano 2020, DOI: 10.1021/acsnano.0c06110

Under UV light, the quantum dots in the wood emitted and scattered an orange light that spread evenly throughout the film’s surface. The team demonstrated the ability of a luminescent panel to light up the interior of a toy house. Different types of quantum dots could be incorporated into the wood film to create various colours of lighting products, the researchers say.