Design of liquid-crystalline electronic functional materials through nanosegregation

Abstract

Conventional liquid-crystalline (LC) semiconductors have been molecules consisting of a π-conjugated moiety and alkyl chains. For example, phenylterthiophene derivatives bearing alkyl chains exhibit ordered smectic phase at room temperature and are applied to field-effect transistors. In this paper, we report a molecular designs of LC electronic materials based on nanosegregation. Terthiophene derivatives bearing an imdazolium moiety exhibit supremolecular smectic phases, in which hole-and ion-conductive layers are formed separately. In the LC phase, electrochrmism is observed under the application of a DC bias without any electrolyte solutions. In simple side-chain LC polysiloxanes bearing terthiophene pendant groups, suprastructures based on nanosegregation are observed. The presence of flexible sublayers consisting of the polysiloxane backbones can relax the applied strain and decrease defect density, resulting in high hole mobility on the order of 10 -2 cm 2 /Vs. For perylene tetracarboxylic bisimide (PTCBI) derivatives bearing oligosiloxane chains, nanosegregation between the rigid aromatic cores and flexible oligosiloxane chains promotes the formation of columnar and layer structures, in which efficient electron transport is observed. The electron mobility in the columnar phase of the PTCBI derivative bearing four trisiloxane chains exceeds 10 -3 cm 2 /Vs at room temperature.

Discotic Liquid Crystals

“…Perylene bisimides 62 bearing oligosiloxane chains were prepared by Funahashi et al (Scheme ) − from bisanhydride 49 which was converted to the alkenyl-substituted bisimide 61 . Catalytic hydrosilylation in the presence of Karstedt catalyst afforded the target compound 62 , which displayed Col ro and Col h phases.…”

Simulation of Crystallization of Pentacene and Its Derivatives from Solution

“…12 Substitution of (long enough) alkyl chain(s) to the elongated aromatic core is a general route to obtain LC materials and liquid crystalline OSCs. 13 8PEN8 is one such OSC material with intrinsic liquid crystallinity, which we exemplified as an OSC material similar to 8BTBT8 in our previous study. 4 In this study, I will compare the simulation results for 8PEN8 with those for pentacene.…”

“…We already examined two of these derivatives in our previous study, that is, 8PEN8 and TIPS-PEN . Substitution of (long enough) alkyl chain(s) to the elongated aromatic core is a general route to obtain LC materials and liquid crystalline OSCs . 8PEN8 is one such OSC material with intrinsic liquid crystallinity, which we exemplified as an OSC material similar to 8BTBT8 in our previous study .…”