Multiscale Confinement and Facile Hierarchical Assembly Enable Full‐Color Circularly Polarized Room‐Temperature Phosphorescent Fibers

ABSTRACT Organic room‐temperature phosphorescent (RTP) materials have attracted increasing attention for optoelectronic applications. However, achieving long‐lived emission, broad color tunability, and chiral optical activity within a single flexible system remains highly challenging. Herein, we report a multiscale confinement and assembly strategy to construct flexible RTP polymer fibers with full‐color‐tunable circularly polarized room‐temperature phosphorescence (CP‐RTP). At the single‐fiber level, spatial confinement within a hydrogen‐bonded polyvinyl alcohol matrix creates a rigid microenvironment that stabilizes triplet excitons of 4‐aminoquinoline, enabling stable blue RTP under ambient conditions with a lifetime of 1.43 s. Incorporation of fluorescein or Rhodamine B as energy acceptors allows efficient phosphorescence‐to‐fluorescence Förster resonance energy transfer (FRET), producing green and red RTP fibers, respectively, and establishing a complete RGB platform within a single polymer system. At the multifiber assembly level, topological confinement arising from helically twisted RGB fiber bundles enables full‐color generation and introduces structural chirality. This configuration allows continuous color mixing across the visible spectrum, ultimately achieving white RTP emission, while simultaneously generating pronounced circularly polarized phosphorescence with a | g lum | value of 1.5 × 10 −2 . This multiscale confinement strategy provides a versatile platform for next‐generation wearable photonics, smart textiles, and secure optical systems.