New Conjugated Bis(AZO) Mesogens with “Push-PULL” Substituents

Phototunable Azobenzene Cholesteric Liquid Crystals with 2000 nm Range

“…[46][47][48][49] These azobenzene chiral dopants have potential advantages in that 1) low concentrations of the dye are required (therefore reducing coloration) and 2) the potential exists for large-range tuning. In materials in which the change in refractive index is small, the tuning range (Dl b ) is equal to the product of the average index and the change in pitch (DP) (Eq.…”

“…[26,27,43] Convergent to these efforts is the use of photosensitive chiral molecules as molecular switches. While the overall goal of these research areas is somewhat dissimilar, the molecules synthesized by Ferringa and co-workers; [32,44,45] Spada, Gottarelli, and coworkers; [46][47][48] and Li et al [49] offer high HTP materials that allow direct accessibility to the pitch of the CLC helix. Most notably, Spada/Gottarelli and later Li developed axially chiral bis(azo) molecules with an HTP of nearly 60 mm À1 in the trans/trans state.…”