Fluorescence spectra of poly(di-n-hexylsilane)/TiO2 nanoparticle hybrid film

The interaction between poly(di-n-hexylsilane) (PDHS) and TiO2 nanoparticle was studied based on the temperature dependence of the fluorescence of a PDHS/TiO2 nanoparticle hybrid film. The polysilane is a suitable probe to investigate a guest polymer–host matrix interaction because the photophysical properties of polysilanes remarkably depend on the conformation of the σ-conjugated Si–Si chain. The PDHS/TiO2 nanoparticle hybrid film showed a fluorescence band assigned to a disordered structure even at 80 K whereas only the fluorescence band of an ordered structure was observed for the PDHS film at 80 K. The disordering of the Si–Si main chain was explained by the perturbation of the n-hexyl side chain in the neighborhood of the TiO2 nanosurface. The non-radiative deactivation of the excited state via the disorder-induced local potential minima was suggested by the temperature dependence of the fluorescence intensities of the disordered and ordered structures in the temperature region from 80 to 160 K.