Sustainable transformation of lignin major motifs to designable room temperature phosphorescence materials

Room-temperature phosphorescence (RTP) materials have emerged as promising platforms for information encryption owing to their unique afterglow characteristics. However, traditional fossil-based RTP systems are limited by poor sustainability and processability. Constructing biomass-derived RTP (BioRTP) materials which bridge the renewable nature of biomass with the structural versatility of synergistic phosphorescent motifs- represents a synergistic and sustainable strategy. Herein, we develop a two-step sustainable strategy to construct high-performance BioRTP systems. First, classical carbazole-benzophenone-based BioRTP luminogens are efficiently synthesized from lignin β-O-4 motifs via high-yield cascade catalytic reactions. Mechanistic investigations reveal the efficient intersystem crossing and suppressed molecular motion for the prominent RTP emission. Second, BioRTP films with three seconds of afterglow property have been fabricated using nature-based sodium carboxymethyl cellulose as matrix. Systematic investigation proves its stronger confinement effects over conventional petroleum-based polymers due to the dense hydrogen-bonding and electrostatic networks. Benefiting from the intrinsic polarity and hygroscopicity of cellulose, the biofilms present humidity and thermo reversibility, hence providing a multicolor anti-counterfeiting platform. As expected, this integrated biomass-based approach bridges sustainability with structural designability, advancing the high-value utilization of lignin.