Colored Gold Ions Enabled High-Transparent and Low-Haze Cellulose Films with Excellent Flame-Retardant and UV to Blue Light-Blocking Performance

The potential dangers associated with UV and high-energy blue light (HEBL) exposure to human ocular health are increasingly attracting scholarly interest due to the escalating use of electronic devices. It is still a great challenge for materials to achieve efficient filtering of UV and HEBL while maintaining low haze and high transmittance. Herein, we reported a facile and green process for fabricating biodegradable and flexible gold ion (Au³⁺)-coordinated cellulose-based light filters with diverse UV- and HEBL-screening capacities via adsorption of Au³⁺. The incorporation of Au³⁺ results in superior UV- and HEBL-screening performance, especially almost 100% absorption of UVA and UVB. Meanwhile, the films could block 67.9–98.8% of HEBL in the 400–450 nm region. By absorption of light, these films can efficiently filter blue light emitted by lighting systems, computer and mobile phone screens. The films maintained exceptionally high transmittance (83.2–86.9%) and low haze (2.1–2.4%). Furthermore, the films exhibited stable UV and HEBL screening under thermal treatment or UV irradiation. Quite encouragingly, the incorporation of Au³⁺ facilitates films in achieving desirable flame retardancy, evidenced by a significant increase in the limiting oxygen index from 19.2% to 39.2%. Compared to the unaltered film, the films containing Au³⁺ demonstrate a marked decrease in peak heat release rate (PHRR) and total heat released (THR), with values declining from 203.8 to 15.5 W/g and 11.7 to 3.0 KJ/g, respectively. Our discoveries grant Au³⁺ a role in the realm of UV to blue light blocking, thus advancing the development of ion-based optical materials for the creation of antiblue light films and devices.