3D Printed Room Temperature Phosphorescence Materials Enabled by Edible Natural Konjac Glucomannan

Abstract Shaping room temperature phosphorescence (RTP) materials into 3D bodies is important for stereoscopic optoelectronic displays but remains challenging due to their poor processability and mechanical properties. Here, konjac glucomannan (KGM) is employed to anchor arylboronic acids with various π conjugations via a facile B─O covalent reaction to afford printable inks, using which full‐color high‐fidelity 3D RTP objects with high mechanical strength can be obtained via direct ink writing‐based 3D printing and freeze‐drying. The doubly rigid structure supplied by the synergy of hydrogen bonding and B─O covalent bonding can protect the triplet excitons; thus, the prepared 3D RTP object shows a striking lifetime of 2.14 s. The printed counterparts are successfully used for 3D anti‐counterfeiting and can be recycled and reprinted nondestructively by dissolving in water. This success expands the scope of printable 3D luminescent materials, providing an eco‐friendly platform for the additive manufacturing of sophisticated 3D RTP architectures.