Direct synthesis and luminescent properties of new silicon-based alternating copolymers

A new class of silicon-based alternating copolymers having a thiophene or fused thiophene unit was synthesized to be used as electroluminescent materials using the Heck reaction between distyrylsilane monomers and appropriate thiophene dibromides. The incorporation of organosilicon units with the aromatic or aliphatic groups on the silicon atoms into π-conjugated systems improved their processability and interrupted the π-conjugation length. The resulting polymers were highly soluble in common organic solvents. They could be spin-cast onto various substrates to give highly transparent homogeneous thin films. Their glass transition temperatures were in the range of 94 to 116°C. The UV-visible absorbance spectra of the resulting polymers appear at the wavelength range of 400 to 416 nm, due to the strong delocalization of the π-conjugated thiophene refits. The silicon-based alternating copolymers showed a strong PL peak at around 512-526 nm in the green region.