Phenanthrene is a condensed aromatic hydrocarbon containing three benzene rings with rigid planes and strong intermolecular π-π interactions. In small molecule semiconductor materials, phenanthrene is often used as an aromatic hydrocarbon center, and stable semiconductor materials can be obtained by introducing flexible chains or continuing to expand the conjugated plane. The phenanthrene materials have the characteristics of high fluorescence quantum yield, relatively balanced carrier transport performance, high thermodynamic stability, simple synthesis, and easy separation and purification. This makes phenanthrene semiconductor materials widely used in the fields of high-efficiency blue fluorescent materials and organic electronic devices.
Figure 1. Chemical structures of phenanthrenes
- Blue Light Material: As the core material of organic light-emitting diodes, organic light-emitting materials play an important role. Excellent blue light materials need to possess three characteristics: blue emission with high color purity, high solid-state luminous efficiency, and high utilization of electrically excited excitons. Selecting appropriate blue light building blocks can well achieve excellent blue light color purity. The phenanthrene materials have the characteristics of large degree of conjugation, good thermal stability, and easy structural modification, and are typical building blocks of blue organic semiconductor materials. The phenanthrene luminescent material obtained by group modification can realize the phenomenon of luminescence enhancement in the aggregated state or solid-state thin film through aggregation-induced luminescence, which greatly improves the luminous efficiency of organic light-emitting diodes.
- Discotic liquid crystal material: The phenanthrene materials can provide aromatic nuclei to form discotic liquid crystals. The group-functionalized phenanthrene material can easily obtain molecular orientation along the direction of the column axis by changing the molecular arrangement in the liquid crystal material, forming a quasi-one-dimensional charge transport channel. This allows the material to achieve relatively high charge carrier mobility. The improvement of charge transport properties also increases the application of phenanthrene discotic liquid crystal materials in the field of organic electronics.
- Hongkun Tian, Jianwu Shi, Shaoqiang Dong, Donghang Yan, Lixiang Wang, Yanhou Geng, Fosong Wang. Novel highly stable semiconductors based on phenanthrene for organic field-effect transistors [J]. Chem. Commun., 2006, 3498-3500.