Related Experiment Video
Updated: Dec 30, 2025
06:24
High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
Published on: October 31, 2019
6.8K
Thermotropic liquid crystal (5CB) on two-dimensional materials.
Paul A Brown1, Sean A Fischer2, Jakub Kołacz2
1ASEE Post-Doctoral Fellow at the U.S. Naval Research Laboratory, Washington, DC 20375, USA.
Physical Review. E
|January 23, 2020
Summary
We studied liquid crystal 5CB on 2D materials like graphene and boron nitride. The substrate choice significantly impacts electronic properties, showing potential for tuning optoelectronics.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Physical Chemistry
Background:
- Liquid crystals (LCs) are crucial for displays and sensors.
- Two-dimensional (2D) materials offer unique electronic properties.
- Combining LCs with 2D materials can lead to novel electronic and optoelectronic devices.
Purpose of the Study:
- Investigate the electronic properties of 4-cyano-4'-pentylbiphenyl (5CB) adsorbed on graphene, hexagonal boron nitride (hBN), and phosphorene.
- Understand the adsorption behavior and electronic interactions between 5CB and these 2D materials.
- Determine how substrate choice influences the electronic and optoelectronic characteristics of the 5CB/2D material system.
Main Methods:
- Density Functional Theory (DFT) calculations were employed.
- Ground-state electronic properties were computed.
- Adsorption energies, electronic band structures, and molecular distortions were analyzed.
Main Results:
- Physisorption of 5CB was found to be robust on all investigated 2D materials, with the strongest binding observed on phosphorene.
- Flexural distortion of the 5CB molecule was significant on graphene and hBN.
- Type-I alignment was observed across all substrates, with the Fermi level within the 5CB HOMO-LUMO gap.
- Qualitatively different band structures emerged, with 5CB's HOMO-LUMO states localizing within the hBN band gap.
- The valence band of hBN exhibited sensitivity to the orientation of 5CB.
Conclusions:
- The electronic properties of 5CB are strongly influenced by the choice of 2D material substrate.
- Substrate-dependent electronic band structures highlight the potential for tailoring optoelectronic properties.
- This work underscores the importance of substrate selection for designing advanced LC/2D material heterostructures.
Related Concept Videos
02:54Molecular and Ionic Solids
19.7K
Crystalline solids are divided into four types: molecular, ionic, metallic, and covalent network based on the type of constituent units and their interparticle interactions.
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
19.7K
02:39Phase Transitions: Vaporization and Condensation
20.4K
The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules...
20.4K
01:19Fluid Mosaic Model
15.4K
Scientists identified the plasma membrane in the 1890s and its principal chemical components (lipids and proteins) by 1915. The model for plasma membrane structure, proposed in 1935 by Hugh Davson and James Danielli, was the first model to be widely accepted in the scientific community. The model was based on the plasma membrane's "railroad track" appearance in early electron micrographs. Davson and Danielli theorized that the plasma membrane's structure resembled a sandwich...
15.4K
01:34The Fluid Mosaic Model
175.9K
The fluid mosaic model was first proposed as a visual representation of research observations. The model comprises the composition and dynamics of membranes and serves as a foundation for future membrane-related studies. The model depicts the structure of the plasma membrane with a variety of components, which include phospholipids, proteins, and carbohydrates. These integral molecules are loosely bound, defining the cell’s border and providing fluidity for optimal function.
175.9K
02:39Phase Transitions: Melting and Freezing
14.4K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
14.4K
02:22Structures of Solids
17.3K
Solids in which the atoms, ions, or molecules are arranged in a definite repeating pattern are known as crystalline solids. Metals and ionic compounds typically form ordered, crystalline solids. A crystalline solid has a precise melting temperature because each atom or molecule of the same type is held in place with the same forces or energy. Amorphous solids or non-crystalline solids (or, sometimes, glasses) which lack an ordered internal structure and are randomly arranged. Substances that...
17.3K