Dendronized organic–inorganic nonlinear optical hybrid materials with homogeneous morphology

To obtain excellent thermal stability, a series of dendronized organic–inorganic hybrids were synthesized and characterized. Dendronized alkoxysilane dyes were prepared via the ring opening addition reaction of azetidine-2,4-dione of chromophore-containing dendrons, with 3-aminopropyltriethoxysilane. Subsequently, the precursor, dendronized alkoxysilane dyes could be hydrolyzed and copolymerized with phenyltriethoxysilane (PTEOS) with the weight ratios of 1:1, 1:3, 1:5 and 1:7 in the presence of water and formic acid. After curing and poling process, organic–inorganic hybrid thin films with homogeneous morphology were obtained. Electro-optical (EO) coefficients (r33) of 2.9–13.0 pm/V were achieved. Due to the site-isolation effect, the sample with high generation dendrons possessed a higher EO coefficient/dye content ratio. In addition, because of the improved miscibility between organic and inorganic segments due to highly branched hydrogen bonding-rich dendrons, NLO polymers with waveguide properties ranging from 3.2 to 4.2 dB/cm at 1310 nm were obtained. These dendronized organic–inorganic NLO hybrids also show greatly enhanced temporal stability at 100 °C.