Stability improvement of C8H2 and C10H2 embedded in poly(vinyl alcohol) films with adsorption on gold nanoparticles

•The Raman signals and stability of polyynes are significantly improved for at least 6 months in composite films.•The thermal stability of C8H2 is better than that of C10H2 and C12H2.•From the Au LIII-edge X-ray absorption spectra, differences may imply the interactions between Au nanoparticles and polyynes.

The surface-enhanced Raman scattering (SERS) spectra of size-separated polyynes C2nH2 (n = 4-6) are reported via using gold nanoparticles as the SERS enhancer for the first time in colloids and poly(vinyl alcohol) films. The observed SERS bands show significantly improved signals and stability for at least 6 months in films. And the thermal stability of C8H2 is better than that of C10H2 and C12H2. The theoretical Raman modes of gold-capped polyynes are investigated by density functional theory. From the Au LIII-edge X-ray absorption spectra, differences were found after adding polyynes to Au colloids or PVA films.

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