In semiconductor materials, carbazole derivatives are important nitrogen-containing aromatic heterocyclic compounds. Its raw materials are easy to obtain and the price is low. Structurally, carbazole derivatives have special rigid condensed rings with strong intermolecular interactions. In property, carbazole derivatives have unique biological activity and optoelectronic properties. In terms of organic synthesis, the structure of carbazole is easy to modify, chemical properties can be adjusted by introducing substituents or functional groups at positions 2, 3, 6, 7, and 9, and various carbazole derivatives can be synthesized to prepare functional materials that meet application requirements. In terms of electronic structure, carbazole derivatives have large conjugated system and strong electron transfer ability within the molecule. In addition, carbazole derivatives also have good thermal stability and optoelectronic properties, showing advantages in the fabrication of organic light-emitting materials and devices. It can be seen that carbazole derivatives show excellent functionality in organic electroluminescent materials, photorefractive materials, solar cell materials, etc.
Figure 1. Chemical structure of carbazole
- Electroluminescent device: Carbazoles are a good class of hole-conducting molecules. Carbazole derivatives are often used as hole-transporting materials with high stability in electroluminescence due to their special rigid structure and easy functionalization at the 3, 6, and 9 positions of their molecules. Carbazole hole materials generally have a "star" structure. Such a steric structure makes the carbazole derivatives have a relatively high glass transition temperature and thus have good thermal stability. In electroluminescent devices, carbazole derivatives exhibit good hole transport properties as well as good blue light emission properties.
- Photosensitizer: Carbazole is an electron-donating group with good planarity. It can expand the planar structure by introducing groups, obtain stronger power supply and hole transport ability, and improve chemical stability. It is an ideal material for designing and synthesizing photosensitizers. By applying carbazole-based photosensitizers to dye-sensitized solar cells, a class of solar cells with excellent electron transport ability and sensitive to light response can be obtained.
- Bogyu Lim, Song-Yi Han, Seo-Hyun Jung, Yu Jin Jung, Jong Mok Park, Wonjoo Lee, Hee-Sang Shim, Yoon-Chae Nah. Synthesis and electrochromic properties of a carbazole and diketopyrrolopyrrole-based small molecule semiconductor [J]. J.Ind. Eng. Chem., 2019, 80, 93-97.