In this work, a liquid crystalline octopolar molecule 1,3,5-tris(ethynylphenyl)benzene-(1)
was successfully embedded as dopant chromophore within a SiO2 based sonogel network in order to
prepare stable solid state hybrid materials with intense second harmonic generation (SHG). This
recently synthesized octopolar compound exhibit a centrosymmetric C3-symmetry structure, which is
constituted by an electron-rich core and electron-poor periphery groups. The sonogel method, induced
by energetic ultrasonic (US) waves applied at the TEOS/H2O reactant mixture interface has proven to
be a suitable route in the manufacture of monolithic hybrid systems suitable for optical
characterizations. The octopolar-based hybrid samples were comprehensively studied in their
morphology, spectroscopic, linear and second-order nonlinear optical (NLO) properties, according to
several characterization techniques: epimicroscopy, AFM, UV-Vis- and fluorescence (PL)
spectroscopies, and the NLO-SHG-technique. Epimicroscopy, photoluminiscent and absorption
spectra evidence an optimal and homogeneous inclusion of the octopolar compounds within the glassy
sonogel network. Without necessity of molecular poling processes, the effective quadratic-NLO
susceptibility χeffS(2) of the hybrid was estimated to 13.6x10-3 pm/V at 1064 nm by SHG-transmission
experiments recorded far-off of the resonance regime.
15 pages. Manuscript submitted and accepted for publication as an article in Mol. Cryst. Liq. Cryst.