New Phenanthrenyl‐Substituted Hybrid Organic‐Inorganic Polysiloxanes for Optoelectronic Applications

Abstract

The current need for polysiloxanes with high refractive index (RI) is very high because of their importance for optoelectronic applications. To meet this demand, a series of novel polysiloxanes derived from phenanthrenyl-containing monomers, including the precursor 1-(9-phenanthrenyl)-1,1,4,4,4-pentamethoxy-1,4-disilabutane, are prepared using the sol-gel technology and free-radical polymerization. The monomer 1-(9-phenanthrenyl)-1,1,4,4,4-pentamethoxy-1,4-disilabutane is synthezised, purified and fully characterized including 2D-NMR experiments for the partial assignment of both its 1 H and 13 C NMR spectra. The molecular weights of the new three-dimentional polysiloxanes with variations in their initial molecular compositions are analyzed using gel permeation chromatography (GPC). The polysiloxanes are characterized by 1 H NMR spectroscopy, and obtained with high RI, thermal stabilities up to 420 °C, and excellent resistance against aging process. The polysiloxanes are coated on silicon-wafers and gorilla glass substrates using respectively the spin-and bar-coating techniques. The coated glasses show optical transmittance above 91 % with excellent hydrophobic character, refractive indexes up to 1.51, and their CIELAB coordinates are also determined. The effects of the crosslinking agent and packing density of the chains on the chemical, optical and mechanical properties of the polysiloxanes and corresponding films are studied.