Photo-stimuli responsive phosphorescence from carbon dots in porous gelatin

Stimuli-responsive phosphorescent materials with dynamic phosphorescent property have great potential in multi-level anti-counterfeiting and high-capacity storage applications. However, achieving such materials still is challenging in that there is no rational design or manufacture method yet. In this work, we report for the first time a facile method to tune the pore size of gelatin film by controlling annealing temperature, and then achieve photo-induced phosphorescence of Carbon dots (CDs) in porous gelatin film. The fabricated [email protected] film can display spatially accurate photoinduced dynamic phosphorescence and their phosphorescence can be activated after photo-irradiation for a few seconds and de-activated by placing in air for a period of time. Our data indicate that dynamic phosphorescence is mainly related to the special micro-nano porous structure of gelatins which is formed during the water evaporation progress. Under light irradiation, triplet excitons generated by CDs embedded in porous gelatin matrix can consume triplet oxygen, leading to phosphorescence photoactivation. When oxygen re-enter the porous [email protected] film, the phosphorescence of the material will disappear. Furthermore, the potential applications of this material were demonstrated in optical patterning and data security.