Light‐Induced Accumulation of Micro‐ and Nanoplastics from Water Dispersion by Optoelectronic Lithium Niobate Platforms

Abstract Plastic contamination in marine and drinking water is a major concern in environmental research. Particularly, detection and identification of micro and nanometric particles remain as important challenges, and so, several emergent methods are currently being investigated. Here, an optoelectronic platform is presented for trapping and accumulating micro/nano‐plastics dispersed in water. The system exploits the photo‐induced electric fields generated by visible light in LiNbO ₃ :Fe crystals. When light is focused on the crystal, the photogenerated electric field triggers successive ejection of tiny droplets from the aqueous sample. These droplets reach the illuminated surface and evaporate leaving behind accumulated particles. Efficient accumulation of polystyrene microparticles is achieved down to 1 µg L ⁻¹ . The influence of plastic concentration and illumination time are characterized. Moreover, the method is further validated at the nanoscale using 140 nm diameter polystyrene (PS) nanoparticles. Its functionality in saline water dispersions is also confirmed although exhibiting a lower efficiency. Finally, the platform´s versatility is demonstrated by accumulating other plastic contaminants such as polyethylene (PE) and polymethyl‐methacrylate (PMMA), and a mix of PE and PS. The resulting accumulation spots serve as suitable samples for plastic identification by Raman spectroscopy. Overall, these results highlight the potential of optoelectronic lithium niobate platforms for micro/nano‐plastics capture, accumulation and Raman identification.