Circularly Polarized Room Temperature Phosphorescence through Twisting-induced Helical Structures from Polyvinyl Alcohol-based Fibers Containing Hydrogen-bonded Dyes

Angew Chem Int Ed Engl. 2024 May 8:e202403391. doi: 10.1002/anie.202403391. Online ahead of print.

Abstract

Room temperature phosphorescence (RTP) materials have garnered significant attention owing to its distinctive optical characteristics and broad range of potential applications. However, the challenge remains in producing RTP materials with more simplicity, versatility, and practicality on a large scale, particularly in achieving chiral signals within a single system. Herein, we show that a straightforward and effective combination of wet spinning and twisting technique enables continuously fabricating RTP fibers with twisting-induced helical chirality. By leveraging the hydrogen bonding interactions between polyvinyl alcohol (PVA) and quinoline derivatives, along with the rigid microenvironment provided by PVA chains, typically, Q-NH2@PVA fiber demonstrates outstanding phosphorescent characteristics with RTP lifetime of 1.08 s and phosphorescence quantum yield of 24.6%, and the improved tensile strength being 1.7 times than pure PVA fiber (172 ± 5.82 vs 100 ± 5.65 MPa). Impressively, the transformation from RTP to circularly polarized room temperature phosphorescence (CP-RTP) is readily achieved by imparting left- or right-hand helical structure through simply twisting, enabling large-scale production of chiral Q-NH2@PVA fiber with dissymmetry factor of 10-2. Besides, an array of displays and encryption patterns are crafted by weaving or seaming to exemplify the promising applications of these PVA-based fibers with outstanding adaptivity in cutting-edge anti-counterfeiting technology.

Keywords: room temperature phosphorescence, circularly polarized phosphorescence, continuous fiber, twisting, hydrogen bonding.