Cyclotriguaiacyclene-functionalized trans-cinnamic acid with alkyl arms:an efficient supramolecular system for solar cell and liquid crystalline applications

摘要

Four novel tri-substituted supramolecular materials(CTGC1-CTGC4)have been synthesized by converting cyclotriveratrylene to cyclotriguaiacyclene followed by esterification using 4-n-alkoxy derivatives of trans cinnamic acid(B1-B4).The synthesized materials were characterized by IR,1H-NMR,13C-NMR,and MALDI-TOF analysis.The liquid crystalline properties of these cinnamate-based trimers were confirmed by polarized optical microscopy,differential scanning calorimetry,thermogravimetry and small and wide-angle X-ray scattering analysis.These compounds displayed an enantiotropic type columnar hexagonal(Colh)phase with broad thermal stability.The higher alkoxy tail substituted mesogens(CTGC3 and CTGC4)with decyloxy and tetradecyloxy groups stabilized the mesophase at 32.0 ℃ and 26.0 ℃,respectively.The synthesized CTG-linked trans-cinnamic acid trimers with alkoxy side groups exhibited self-assembly,which makes them good candidates for device applications.The current-voltage relationship indicates the ohmic-type behavior for the pristine and 100 ℃ annealed films while 200 ℃ films showed deviation.The optical properties indicate the high transmittance of 200 ℃ annealed films in visible and near IR regions.As wide optical energy band gaps of 2.93 eV,2.87 eV and 3.45 eV were observed for CTGC3 thin films,they could be utilized as optical window in second and transport layers in third generation solar cells.