Metal-free transparent luminescent cellulose films

As functional materials, luminescent films have a wide range of applications in terms of displays, light-emitting devices, safety signs and sensors. Cellulose is the most abundant renewable resource in the world and plays an important role in the field of membrane synthesis. Here, cellulose was dissolved in 7 % NaOH/12 % urea aqueous solution, and the regenerated cellulose films were prepared in acid media. N and S doping carbon quantum dots (C-QDs) were synthesized as the high-efficiency luminescent materials, and the nanocomposite films of cellulose/C-QD were prepared by fixing the C-QDs onto the surface of regenerated cellulose fibers. Fourier transform infrared spectrometry, X-ray diffraction, atomic force microscopy and scanning electron microscopy measurements were used to measure the structure and properties of the film. The as-prepared film was transparent and luminescent in the visible region with high mechanical strength. In addition, no metal was involved in the luminescent film, which makes it safe and lightweight, and the film has potential applications in many fields.

Metal-free cellulose/carbon QDs composite film was prepared, and the film was highly transparent and luminescent.