Molecular conductors, also known as conductive molecular crystals, include semiconductors, conductors and superconductors. Molecular conductor is a new crystalline material structure form different from ionic crystals, covalent crystals, metal crystals and molecular crystals. Its structural feature is that conductive components (planar conjugated molecules in the form of free radicals) are packed tightly and orderly in the crystal, and π electron clouds between molecules overlap to form energy bands. Unlike ordinary molecular crystals, molecular conductors have intermolecular interactions far greater than van der Waals forces, and are widely used in molecular electronic devices, bioelectrodes, sensor materials and other fields. At present, such materials are mainly complex molecular conductors, and the charge carriers are provided by chemical doping, with abundant oxidation states and high conductivity. It is worth noting that the crystal structure of a molecular conductor has a great influence on its energy band structure and conductivity. The homogenization of molecules and the spacing of conductive components are structural factors that help increase the conductivity of molecular conductors.
Figure 1. The chemical structure of some common molecular conductors
- Solar cell: Molecular conductor photovoltaic has the advantages of clear structure, convenient synthesis, and easy purification. It can be used to prepare thin, light, and flexible large-area flexible materials for solar cells. The intermolecular π-π stacking and strong intermolecular interaction of molecular conductors are conducive to improving the carrier mobility of the device. The single junction efficiency has exceeded 16%, which can significantly improve the photoelectric conversion efficiency of solar cells.
- Photoelectrochemical sensor: The signal excitation source of the photoelectrochemical sensor is light, and the detection signal is electricity. The two belong to different energy forms, so they have the characteristics of low background signal, high sensitivity and easy miniaturization. According to different biological analysis fields, the sensing modes of photoelectrochemical sensors include aptamer sensors, enzyme sensors, immunosensors and cell sensors. Molecular conductors can be used as electrode materials in the detection part of photoelectrochemical sensors, which have the advantages of high sensitivity, high response, and cheap materials.
- Lahcène Ouahab,Takehiko Mori. Molecular Conductors [J]. Eur. J. Inorg. Chem., 2014, 24, 3783-3784.