As an important chemical raw material, secondary arylamines has a very wide range of uses. Secondary arylamines refers to an amine compound containing two aromatic substituents. In the structure of secondary arylamines, the N atom can absorb electrons on the aromatic ring through the inductive effect. On the other hand, the non-conjugated electron pair on the N atom forms a p-π conjugation effect with the aromatic ring, making the aromatic ring rich in electrons. On the other hand, the non-conjugated electrons on the N atom can form a p-π conjugation effect with the aromatic ring, making the aromatic ring rich in electrons. The interaction between the two makes secondary arylamines have better electron donating properties, lower ionization potential, higher hole mobility, better solubility, better amorphous film formation, and stronger fluorescence properties, etc. In terms of applications, secondary arylamines were initially mainly used as materials such as dyes, spices, pesticides, pharmaceutical synthesis intermediates, and plastic stabilizers. With the development of semiconductor materials, secondary arylamines with strong chemical structure controllability have been developed, and are widely used in the field of optoelectronic devices as light-emitting materials and hole transport materials.
Figure 1. Chemical structures of secondary arylamines
- Hole transport material: In optoelectronic devices, the hole transport layer can improve the transport rate of holes in the device and effectively block electrons in the light-emitting layer to achieve maximum recombination of carriers, thereby improving the brightness, lifetime and efficiency of the device. Secondary arylamines compounds have good hole transport rates due to intermolecular p-π conjugation. The active hydrogen atoms on the N atom are also easily substituted to form more stable materials by coupling with other compounds. Such materials can form ammonium ion radicals under the action of an electric field, have high hole mobility and good transport properties, and are a class of hole transport materials with excellent properties. Secondary arylamines hole transport materials can be used in the fields of organic solar cells, field effect transistors, organic electroluminescent diodes and the like.
- Luminous material: Secondary arylamines compounds have unpaired electrons on the N atom and can form complexes with metals. These complexes have strong phosphorescent emission and can be used as phosphorescent materials with high quantum yield in the field of organic electroluminescent diodes. In addition, the multifunctional aromatic ring can modify the secondary arylamines e luminescent material, thereby further improving the luminescent lifetime and quantum yield of the material.
- Phillip Brogdon, Fabrizio Giordano, George A. Puneky, Amala Dass, Shaik M. Zakeeruddin, Mohammad Khaja Nazeeruddin, Michael Grätzel, Gregory S. Tschumper,Jared H. Delcamp. A Computational and Experimental Study of Thieno[3,4-b]thiophene as a Proaromatic π-Bridge in Dye-Sensitized Solar Cells [J]. Chem. Eur. J, 2016, 22, 694-703.