Indoor lighting can set the mood, from bright, stimulating colors to a dim, romantic glow. However, most materials used for lighting, including plastics, are not eco-friendly. Researchers from New Zealand and Switzerland have developed a bio-based, water-resistant, luminescent wood film that could be used as cover panels for displays, lamps, and even laser devices. The team published their findings on September 28, 2020, in the American Chemical Society ACS Nano.
The growing consumer demand for eco-friendly, sustainable, and renewable materials has motivated researchers worldwide to explore wood-based thin films for optical applications. However, many materials developed so far have their flaws, including uneven lighting, low mechanical properties, the need for a petroleum-based polymer matrix, or a lack of water resistance. Qiliang Fu and Ingo Burgert, the lead authors of the study, wanted to create a luminescent wood film that overcomes these defects and limitations.
The team began by treating balsa wood with a solution to extract lignin and around 50% of the wood’s hemicelluloses, leaving behind a porous scaffold. Then, they infused the delignified wood with a solution comprising quantum dots (semiconductor nanoparticles that emit light of various colors when exposed to ultraviolet (UV) light.) Finally, the researchers compressed and dried the wood, then applied a hydrophobic coating.
The final result was a water-resistant, dense wood film with exceptional mechanical properties. When the UV light hits the wood during tests, the quantum dots emitted and scattered an orange glow that spread evenly throughout the film’s surface. The researchers demonstrated the luminescent wood film’s ability to light up the inside of a toy house. Interestingly, different kinds of quantum dots could be integrated into the wood to create an assortment of colors for lighting products.
