Triphenylenes For Semiconductors
Triphenylene, also known as 9,10-triphenylene, is a polycyclic aromatic hydrocarbon with D3h molecular symmetry and delocalized 18-π electron system, and has high thermal and chemical stability. Triphenylene derivatives are composed of a rigid core of triphenylene and various flexible chains around it, and are a class of ideal semiconductor materials. In order to further improve the properties of triphenylenes materials, alkoxy chains, thiooxy chains, ester groups, fluorine-substituted alkyl chains, hydroxyl groups, and various unsaturated side chains can be introduced into the triphenylene molecule to modify its structure. The introduction of some flexible groups has a great influence on the charge transport properties of triphenylene semiconductor materials. Charge transport properties are an important factor affecting the properties of organic semiconductor materials. Good charge transport properties make triphenylene semiconductor materials widely used in optoelectronic and microelectronic fields such as organic light-emitting diodes, field-effect transistors, and organic photovoltaic devices.
Figure 1. Chemical structures of triphenylene
Applications:
- Luminescent material: The properties of triphenylene derivatives can be modified by adjusting the substituent groups. Such derivatives have larger intramolecular electron density and molecular steric hindrance, and weaker intermolecular π-π interactions, resulting in higher intramolecular quantum efficiency and shorter emission wavelengths. Such triphenylene derivatives can hinder the formation of organic intermolecular excimer-excited complexes, increase the internal electron density and stability. Therefore, the luminous efficiency and lifetime of the organic light-emitting diode prepared by the triphenylene derivatives are significantly improved.
- Liquid crystal material: Thin film field effect transistor liquid crystal displays generally use rod-shaped liquid crystal materials with positive birefringence. The anisotropy of the rod-shaped crystal material easily causes light leakage of the display. The triphenylenes discotic liquid crystal material has negative birefringence and can be used as an optical compensation film to compensate the optical path difference. This kind of optical compensation film has a synthetic liquid crystal phase temperature and a lower cooling point, which can ensure that the optical compensation film can be used in a thin film field effect transistor liquid crystal display within a suitable temperature range.
- Carrier transport materials: The discotic liquid crystal material is a one-dimensional ordered structure formed by stacking discotic molecules, and has high charge transport efficiency in one-dimensional direction. Triphenylene derivatives with flexible side chains are a good class of discoid molecules. This kind of discoid molecules forms liquid crystal materials with ordered nematic phase or ordered columnar phase and lamellar phase through the π-π interaction between benzene rings. Triphenylene liquid crystal materials have high carrier mobility, and can be used as optoelectronic materials in the fields of thin film transistors, organic light emitting diodes and organic photovoltaic devices.
Reference
- He Q, Huang H, Yang J. Synthesis and spectroscopic properties of a series of hyperbranched conjugated molecules with 1, 3, 5-triphenylbenzene as cores[J]. Journal of Materials Chemistry, 2003, 13(5), 1085-1089.
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