Nanostructured liquid-crystalline semiconductors – a new approach to soft matter electronics

Abstract

In contrast to solid-state organic semiconductors, superstructures can be constructed in liquidcrystalline (LC) phases, using chirality, hybridization with nanofibers, and nanosegregation. Chiral LC molecules form LC phases with helical structures. Gelator molecules self-assemble into fibrous aggregates in LC phases to form nanohybrid materials. Liquid crystal molecules consisting of π-conjugated moieties and incompatible functional parts form nanosegregated LC phases. These nanostructured π-conjugated LC materials have the potential to create new soft matter with unique photonic and electronic functions.

Nonlinear Nonacenes with a Dithienothiophene Substructure: Multifunctional Compounds that Act as Columnar Mesogens, Luminophores, π Gelators, and p‐Type Semiconductors

“…[22][23][24][25][26] The design of novel π-conjugated polycyclic cores is therefore the key to improve the performances of liquid-crystalline (LC) semiconductors. In the last decade, LCs based on fused-thiophene subunits have been flourishing, and organic mesogenic derivatives of oligothiophenes, [27][28][29][30][31][32] thienothiophenes (TT), [33,34] dithienothiophenes (DTT), [35][36][37][38][39][40] benzothiophenes (BT), [41][42][43][44] benzotrithiophenes (BTT), [45,46] benzothieno [3,2-b]benzothiophene (BTBT), [47][48][49][50][51][52] materials have been amply reported. Such compounds exhibit high charge mobility with usual rates up to about 10 cm 2 V À 1 s À 1 for a rod-like mesogen [52] and nearly 0.2 cm 2 V À 1 s À 1 for a discotic mesogen, [45] in their highly ordered crystalline phases, directly obtained after annealing from their mesomorphic temperatures and slowly cooled down.…”

Fluorescent N‐Heteroacene‐Based π‐Conjugated Liquid Responsive to HCl Vapor

“…Organic functional materials have attractive attentions because these materials are applied into inexpensive and flexible devices, compared to inorganic hard materials fabricated from silicone which is a representative substance for the development of 20th industry. [1][2][3][4][5] Among them, functional soft materials such as liquid crystals, [6][7][8][9][10] gels, [11][12][13][14][15][16] and polymers [5,[17][18][19][20] are candidates to develop organic electronics. For a construction of various self-organized superstructures in nano levels, molecular designs programmed by non-covalent intermolecular interactions such as hydrogen bondings, p-p interactions, van der Waals force, and nanosegregation are efficient strategies in condensed states.…”

Design of liquid crystals: from a nematogen to thiophene-based π-conjugated mesogens

“…[15,16] In the LC phases, overlaps between π-molecular orbitals of the core parts produce charge transport. [30][31][32][33][34] M. Funahashi and T. Kato…”