Multicolor room temperature phosphorescence cellulose with source-boosting effect for information encryption

Cellulose is an environmentally friendly biopolymer with a structure that contains a large number of hydroxyl groups, making it easy to form a hydrogen bond network. With proper design, it has the potential to become an excellent room temperature phosphorescent (RTP) material. In this study, we present a straightforward and adaptable approach for linking arylboronic acid chromophores to cellulose chains via B & horbar;O covalent bonds in pure water, leading to multicolor RTP cellulose. By increasing the conjugation of the chromophores, the emission color of RTP can be adjusted from blue-green to red. Cellulose promotes the spin-orbit coupling (SOC) effect of the arylboronic acid groups and enhance the intersystem crossing (ISC) process. The rigid environment formed by B & horbar;O covalent and hydrogen bonds stabilizes the triplet excitons and suppresses the nonradiative leaps, which results in excellent RTP performance with a lifetime of 1.85 s and an afterglow of up to 18 s. It is important to note that the formation of various emissive species results in excitation-dependent persistent luminescence in the RTP cellulose system. Therefore, given the exceptional sustainability of cellulose materials, RTP cellulose films have tremendous potential in applications such as persistent luminescence displays, dual-mode information encryption, and advanced anti-counterfeiting.