Stimuli‐Responsive Multicolor Nacre‐Mimetic Phosphorescent Bionanocomposite Thin Films via Network‐Confinement Coupling

Dynamic room temperature phosphorescent (RTP) materials have garnered much attention for applications in anti-counterfeiting and information encryption. However, developing dynamic bionanocomposite thin films (BTFs) featuring long-lived RTP emission remains a formidable challenge. Herein, an efficient and straightforward network-confinement coupling strategy is presented to create stimuli-responsive multicolor nacre-mimetic phosphorescent BTFs by embedding 3-amino-9-ethylcarbazole molecules into polyvinyl alcohol-entangled collagen molecules and assembling with tannic acid-mediated α-zirconium phosphate nanoplatelets via phosphorescence resonance energy transfer. The structural nanoconfinement effects enabled by the nanoplatelets not only resulted in nacre-like brick-and-mortar microstructure but also effectively suppressed the quenching effect from ambient oxygen, promoting RTP efficiency. Moreover, the RTP emission of the BTFs exhibited dynamic sensitivity to both water and heat stimuli owing to the disruption of the hydrogen-bonding networks, leading to reversible RTP quenching. Importantly, the interlayer entanglement in the BTFs significantly enhanced the RTP performance, achieving an ultralong lifetime up to 1075.1 ms and an afterglow lasting 11.0 s. Furthermore, leveraging their stimuli-responsiveness and color-tunability, the BTFs' components are demonstrated as water-soluble phosphorescent inks to prepare multimodal anti-counterfeiting patterns and be applied for light-switchable information encryption. This work offers a promising strategy for rational design and development of stimuli-responsive multicolor materials for advanced functional applications.