One-Step Synthesis of Eu3+-Modified Cellulose Acetate Film and Light Conversion Mechanism.

A CA-Eu(III) complex was synthesized by the coordination reaction of cellulose acetate (CA) and Eu3+ to obtain a CA-Eu light conversion film. This product was then doped with Tb(III) to sensitize the luminescence of Eu3+, which could functionalize the CA film. FTIR and XPS showed that the oxygen atoms in C=O, C-O (O=C-O), and O-H were involved in the complexation with Eu3+ and formed a Eu-O bond. SEM revealed that Eu3+ filled in the pores of the CA film. By changing the experimental conditions, the best fluorescence performance was obtained at the CA: Eu3+ ratio of 3:1 with a reaction time of 65 min. The energy transfer between Tb3+-Eu3+ could be realized by doping Tb3+ to enhance the luminescence of Eu3+. The best fluorescence performance of the CA-Eu-Tb light conversion film was at a Eu3+:Tb3+ ratio of 3:1. Compared with the CA film, the light conversion film has high transparency, high tensile strength, and good flexibility. It can convert the ultraviolet light harmful to plants into red light that is beneficial to photosynthesis. This offers high efficiency and environmental protection in the field of agricultural films.