From Landfill to Photonics: The Upcycling of Plastic Waste

The unrestrained use and improper disposal of plastics make their recycling and reuse an issue of paramount importance. This work aims to give a second life to polymeric materials in the field of photonics and shows that recycled polymers, which are often mixed with additives that affect their processability for such a challenging target, can be used for the fabrication of multilayered photonic crystals. We focus on simple methods to recover polystyrene from disposables and food packaging and cellulose acetate from cigarette butts. Also, we demonstrate the use of combustion residues filtered in the butts as fluorophores with impressive broadband luminescence that can be used to dope the photonic structures themselves. The optical quality of the fabricated photonic structures is comparable to that obtained with pure commercial polymers. However, changes in the optical response of the photonic crystals suggest that the formulation of the recycled material plays a crucial role in the growth steps. Also, a clear spectral redistribution is observed in the fluorescence of cellulose acetate derived from cigarette butts, confirming the quality of the photonic structures fabricated with recycled materials and fluorophores. Therefore, this fabrication approach opens the possibility of using recycled polymer waste for the growth of photonic and fluorescent nanostructures of high optical quality.