Color-Tunable, Excitation-Dependent, and Water Stimulus-Responsive Room-Temperature Phosphorescence Cellulose for Versatile Applications

Smart-response materials with ultralong room-temperature phosphorescence (RTP) are highly desirable, but they have rarely been described, especially those originating from sustainable polymers. Herein, a variety of cellulose derivatives with 1,4-dihydropyridine (DHP) rings are synthesized through the Hantzsch reaction, giving impressive RTP with a long lifetime of up to 1251 ms. Specifically, the introduction of acetoacetyl groups and DHP rings promotes the spin-orbit coupling and intersystem crossing process; and multiple interactions between cellulose induce clustering and inhibit the nonradiative transitions, boosting long-live RTP. Furthermore, the resulting transparent and flexible cellulose films also exhibit excitation-dependent and color-tunable afterglows by introducing different extended aromatic groups. More interestingly, the RTP performance of these films is sensitive to water and can be repeated in response to wet/dry stimuli. Inspired by these advantages, the RTP cellulose demonstrates advanced applications in information encryption and anti-counterfeiting. This work not only enriches the photophysical properties of cellulose but also provides a versatile platform for the development of sustainable afterglows. Combined with the advantages of conventional conjugated aromatic luminescence and macromolecular cluster luminescence, a variety of cellulose derivatives with 1,4-dihydropyridine rings are synthesized through the Hantzsch reaction. The resulting transparent films exhibit color-tunable, excitation-dependent, and water stimulus-response afterglows, giving an impressive room-temperature phosphorescence lifetime of up to 1251 ms.image

Automated summary

This study presents the synthesis of cellulose derivatives with 1,4-dihydropyridine rings, resulting in materials with ultralong room-temperature phosphorescence. The cellulose films also exhibit excitation-dependent and water stimulus-response afterglows, making them suitable for applications in information encryption and anti-counterfeiting.