Functionalized Porphyrin Discotic Liquid Crystals: Photoinduced Charge Separation and Trapping

Abstract

Individual members of a family of highly absorptive porphyrins bearing symmetrically positioned flexible side chains form discotic liquid crystalline mesophases at modest temperature ranges. The order of this phase is preserved when a thin layer of this self‐assembled material is cooled to room temperature. Exposure of such films to visible excitation, with or without an externally applied electrical field, produces photovoltaic effects and/or charge trapping. The latter effect constitutes the basis for optoelectronic information storage.

Discotic Liquid Crystals

“…It then took until 1987, when Gregg et al reported porphyrin octaesters as new discotic liquid crystals . Since then a huge variety of porphyrin derivatives have been explored and progress has been summarized previously. , In 2009 Shearman et al reported the phase transition behavior of β-octaalkyl porphyrins 206 and 207 (Scheme ). Whereas the free macrocycles 206 were nonmesomorphic, the corresponding Zn complexes 207 displayed Col r phases.…”

Novel Discotic Boroxines: Synthesis and Mesomorphic Properties

“…From a molecular perspective, several scaffolds have turned out to be successful candidates for the nanosegregation, which ultimately led into the formation of columnar mesophases. Besides tri- and hexasubstituted benzenes, in particular triphenylenes [ 10 ], perylenes [ 11 ], hexa- peri -hexabenzocoronenes [ 12 , 13 ], porphyrins [ 14 , 15 ], phthalocyanines [ 15 ], quinoxalines and other aza analogues of polycyclic aromatic hydrocarbons were used as mesogenic subunits. However, not only disk-shaped mesogens, but also non-conventional [ 16 ] and supramolecular and hydrogen bonded liquid crystals [ 17 ] can self-assemble into columnar aggregates.…”

Self-Assembled Monolayers of Discotic Liquid Crystalline Thioethers, Discoid Disulfides, and Thiols on Gold: Molecular Engineering of Ordered Surfaces

“…Organic compounds have been discussed as potential candidates for application as components of electronic devices for over a decade . The high degree of organization of the investigated systems, such as Langmuir−Blodgett (LB) films or liquid crystals, is a prerequisite for a good performance of the material. Recently, discotic liquid crystals have been discussed as new materials in photoconducting systems and photovoltaic instruments .…”