2009•Journal of the American Chemical SocietyRequires access
Laterally Azo-Bridged H-Shaped Ferroelectric Dimesogens for Second-Order Nonlinear Optics: Ferroelectricity and Second Harmonic Generation
Yongqiang Zhang, Josu Martínez-Perdiguero, Ute Baumeister, Christopher M. Walker, J. Etxebarría, Marko Prehm, Josu Ortega, Carsten Tschierske, Michael J. O'Callaghan, Adam W. Harant, Mark A. Handschy
Open publisher page 40 citations
Abstract
Two classes of laterally azo-bridged H-shaped ferroelectric liquid crystals (FLCs), incorporating azobenzene and disperse red 1 (DR-1) chromophores along the FLC polar axes, were synthesized and characterized by polarized light microscopy, differential scanning calorimetry, 2D X-ray diffraction analysis, and electro-optical investigations. They represent the first H-shaped FLC materials exhibiting the ground-state, thermodynamically stable enantiotropic SmC* phase, i.e., ground-state ferroelectricity. Second harmonic generation measurements of one compound incorporating a DR-1 chromophore at the incident wavelength of 1064 nm give a nonlinear coefficient of d(22) = 17 pm/V, the largest nonlinear optics coefficient reported to date for calamitic FLCs. This value enables viable applications of FLCs in nonlinear optics.