Fabrication of Photocrosslinked Polysilane/diarylfluorene Blended Films with Tunable Refractive Indices

Abstract

We have developed the photocrosslinked films of a diphenyl- or dinaphthylfluorene having epoxy and oxetane moieties and polysilanes blends in the presence of a photoacid generator by irradiation at 405 nm. Photo-induced decomposition of the Si-Si bonds of the polysilanes was successfully suppressed during the visible light irradiation. The cationic photocrosslinking properties of the blends were strongly affected by the post-exposure-bake conditions and irradiation dose. Polysilane moieties were incorporated into the film by the termination reaction of the polymerization with the terminal OH groups. We have successfully fabricated films with high refractive indices (n_d: 1.70) and the refractive index values were tunable by irradiation at 254 nm due to the decomposition of the Si-Si bonds of the polysilanes.