Large nonlinear optical activity from hybrid inorganic–organic films with fluorinated benzene as isolation group

• Inorganic-organic hybrid films are prepared via sol-gel process of alkoxysilane dyes
• Nonlinear optical properties of hybrid films are investigated
• Fluorinated benzene group effectively improves the nonlinear optical property

Two azo chromophores containing fluorinated benzene and alkyl chain as isolation group were designed and synthesized, respectively, and the corresponding alkoxysilane dyes were obtained by coupling 3-isocyanatopropyltriethoxysilane with the chromophores. The molecular structures were verified by elemental analysis, hydrogen nuclear magnetic resonance, and Fourier transform infrared spectrum. Followed by a sol–gel process of the alkoxysilane dyes, inorganic–organic hybrid films were prepared by spin-coating. After electric poling, these hybrid films show the higher nonlinear optical (NLO) response than their analog containing chromophore DR1. Furthermore, the fluorinated benzene group exhibits better enhanced effect than the flexible alkyl group. The highest NLO coefficients (d33) of the hybrid film containing fluorinated benzene group was determined to be 140.5 pm V− 1 at the chromophore concentration of 40%.