Polyynes with aggregation-induced emission characteristics: synthesis and their photonic properties

Tetraphenylethene-containing diacetylenes are synthesized and their homopolymerizations are catalyzed by CuCl in o-dichlorobenzene, furnishing linear polyynes in high isolated yields. All polymers possess good solubility in common organic solvents and enjoy high thermal stability. Whereas they are practically non-emissive when molecularly dissolved in good solvents, they become highly emissive when aggregated as nanoparticle suspensions in poor solvents or fabricated into thin films in the solid state, demonstrating a novel phenomenon of aggregation-induced emission. The polymers are highly transparent, allowing almost all light in the entire visible spectral region to transmit through. Thin films of the polymers show high refractive indices (n=1.7787~1.6543) in the wavelength region of 400~1700 nm and very low chromatic aberrations (D'=0.0003). Their n values can be modulated and their thin films can be crosslinked by UV irradiation, generating fluorescent patterns with high resolutions.