Realizing Multicolor, 3D-Printable Ultralong Room Temperature Phosphorescence PLA Materials via Regulating the π-System of Aryl-Annulated Carbazoles.

Bio-based degradable organic ultralong room temperature phosphorescence (URTP) polymers should become a mainstream research topic in the future. Meanwhile, shaping URTP polymers into 3D-printable materials is of great significance for applications in optical and optoelectronic fields. Nevertheless, the fabrication of full-color, ultralong, bright, and 3D printable bio-based RTP polymer materials using a single-dopant component still faces significant challenges. Here, by regulating the π-system of aryl-annulated carbazoles, the triplet energy levels are successfully regulated which enabled wavelength-tunable RTP emissions spanning from blue to red afterglow (440 - 628 nm) in PLA matrix. Non-radiative decay of dopant triplet excitons are effectively suppressed by the rigid environment of polymer matrix and dopant-polymer interactions. This enables the prepared PLA-based RTP materials exhibited ultralong lifetimes of 3.84 s and the naked-eye-visible afterglow duration up to 48 s. Recyclable and reprocessable RTP objects are fabricated via 3D printing and are successfully applied in the fields of artworks, monitoring and anti-counterfeiting. This successfully expands the application of polymer-based RTP materials in 3D fields, and will promote the commercialization of RTP materials and the development of environmentally friendly ultralong RTP materials.