Enhanced Room-Temperature Phosphorescence in Delignified Wood Through Combination with Pyrene-Based Materials

Organic room-temperature phosphorescent (RTP) materials, featured by their large Stokes shifts and long lifetimes, have garnered significant attention due to their promising applications in biophotonics and optoelectronics. However, the instability of their triplet states and their proneness to quenching in aerobic, room-temperature environments pose significant challenges. Herein, delignified wood (DW) is used as a porous substrate and applied heat to drive dehydration condensation between cellulose/hemicellulose hydroxyls and the phosphorescent chromophore 1-pyrenylboronic acid (Py-BOH). This reaction forms B─O bonds, anchoring Py-BOH in a rigid microenvironment created by hydrogenbonding in the DW pores, which restricts molecular thermal motion and facilitates the RTP emission, resulting in a lifetime of 340 ms for the target RTP-DW film. Furthermore, due to the susceptibility of the cellulose hydrogen-bond network to disruption by water molecules, the RTP-DW film is sensitive to water and exhibits repeatable stimulus-responsive behavior under water/thermal stimulation. This material can be processed into various luminous objects by directly cutting the wood film into different shapes or grinding it into powder and compounding it with polymers, thereby holding potential applications in luminous indication and anti-counterfeiting. The successful preparation of this (room-temperature phosphorescent-delignified wood)RTP-DW film will provide an effective pathway for achieving high-value utilization of wood resources.