Carrier Transport Switching of Ferroelectric BTBT Derivative.

Alkylamide-substituted [1]benzothieno[3,2-][1]benzothiophene () derivative of -NHCOCH (), which has ferroelectric N-H···O= hydrogen-bonding network of alkylamide group and two-dimensional (2D) electric structure of π-cores, was prepared to design the external electric field-responsive organic semiconductors. The short-chain derivative of NHCOCH () revealed the coexistence of a 2D electronic band structure based on the herringbone arrangement and the one-dimensional (1D) hydrogen-bonding chain. formed a smectic E (SmE) liquid crystal phase above 412 K and showed ferroelectric hysteresis in the electric field-polarization (-) curves at 403-433 K.

Biased Bowl-Direction of Monofluorosumanene in the Solid State.

A new curved π-conjugated molecule 1-fluorosumanene () was designed and synthesized that possesses one fluorine atom on the benzylic carbon of sumanene. This compound can exhibit bowl inversion in solution, leading to the formation of two diastereomers, and , with different dipole moments. Experimental and theoretical investigation revealed an energetical relationship among , , and solvent to realize the various : ratios in the single crystals of depending on the crystallization solvent.

Ferroelectric Organic Semiconductor: [1]Benzothieno[3,2-][1]benzothiophene-Bearing Hydrogen-Bonding -CONHCH Chain.

An alkylamide-substituted [1]benzothieno[3,2-][1]benzothiophene () derivative of -CONHCH () and CH--CONHCH () were prepared to design the multifunctional organic materials, which can show both ferroelectric and semiconducting properties. Single-crystal X-ray structural analyses of short-chain (-CONHCH) derivatives revealed the coexistence of two-dimensional (2D) electronic band structures brought from a herringbone arrangement of the π core and the one-dimensional (1D) hydrogen-bonding chains of -CONHCH chains. The thin films of and fabricated on the Si/SiO substrate surface have monolayer and bilayer structures, respectively, resulting in conducting layers parallel to the substrate surface, which is suitable for a channel layer of organic field-effect transistors (OFETs).

Supramolecular Complexation and Collective Optical Properties Induced by Linking Two Methyl Salicylates via a σ-Bridge.

Supramolecular complexes or polymers, formed by noncovalent intermolecular forces such as π-π and dipole-dipole interactions, have the potential to render collective optical properties brought about by excitons spreading over multiple molecules, as seen in J-aggregates. In this respect, molecules with a large π-system and dipole moment are advantageous. However, we report here that methyl salicyate (MS) dyad-type molecules, synthesized by connection of two MSs via a σ-bridge, are effective for forming stable aggregates with collective optical properties.

Dynamics of Chiral Cations in Two-Dimensional CuX and PbX Perovskites (X = Cl and Br).

Chiral organic ammonium cations (()-2-methylphenethylammonium (-MPhA) and ()-3,7-dimethyloctylammonium (-DMOA)) cations were combined with [MX] anions (M = Cu and Pb, X = Cl and Br) to form two-dimensional (2D) perovskites: (-MPhA)CuCl (), (-MPhA)CuBr (), (-DMOA)CuCl (), (-DMOA)CuBr (), (-DMOA)PbCl (), and (-DMOA)PbBr (). The point shearing of the MX octahedron formed 2D perovskite layers, which were sandwiched by the bilayer molecular assembly of chiral organic ammonium cations. We found that the flexible and polar organic -MPhA and -DMOA cations in the 2D perovskites played an important role in the phase transition behavior and dielectric responses.

Nanoscale Effects in One-Dimensional Columnar Supramolecular Ferroelectrics.

Organic ferroelectrics have been actively developed with the goal of fabricating environmentally friendly and low-cost memory devices. The remanent polarization of hydrogen-bonded organic ferroelectrics approaches that of the inorganic ones. Nanoscale fabrication of organic ferroelectrics is an essential aspect of high-density memory devices.