Phenylpyridine compounds are a class of compounds formed by the coupling of phenyl and pyridine. According to the position of coupling, it can be divided into 2-phenylpyridine, 3-phenylpyridine and the like. Due to the nitrogen atom on the pyridine ring, such compounds are often prepared as ligands as complexes. Phenylpyridines are widely used in the field of optoelectronic materials due to their electron deficiency, oxidation resistance and excellent thermal stability. Using phenylpyridine as a building block, a new type of phosphorescent host material can be synthesized for use in organic electroluminescent devices. At the same time, the thermal stability of phenylpyridine-based materials and the regulation of molecular orbital energy levels are further improved through molecular structure design, so that they can be used as transport materials in the field of solar cells.
Figure 1. Chemical structures of phenylpyridine
- Organic Electroluminescent Devices (OLEDs): Light-emitting materials in OLEDs are divided into fluorescent materials and phosphorescent materials. Transition metal-organic complexes (Pt, Os, Ir, Re, etc.) play an important role in the preparation of efficient OLEDs. Among them, Ir complexes are an important class of phosphorescent materials due to their short triplet lifetime, high efficiency and low preparation cost. The nitrogen atom of the phenylpyridine compound makes it a good ligand to form complexes with Ir. Such complexes have short lifetimes, avoid triplet exciton quenching, and have high luminous efficiency. Introducing fluorine, trifluoromethyl, cyano, acyl, and sulfonic acid groups into the phenylpyridine-iridium complex can achieve better electrophosphorescence performance and improve the luminous efficiency of OLEDs devices.
- Organic Solar Cells: Phenylpyridines are a class of π-conjugated N,C-ligand compounds. The molecular skeleton of phenylpyridine complexes tends to be flat, and the π-conjugation shows an enhanced trend, which can effectively increase the electron affinity of the molecule. This makes phenylpyridine complexes a class of efficient electron transport materials. Moreover, phenylpyridine complexes have low LUMO/HOMO (lowest unoccupied molecular orbital/highest occupied molecular orbital) energy gap and high electron mobility, which can improve the photoelectric conversion efficiency of organic solar cells as electron transport materials.
- Diego Cortés‐Arriagada, Paulina Dreyse, Felipe Salas, Iván González. Insights into the luminescent properties of anionic cyclometalated iridium(III) complexes with ligands derived from natural products [J]. Int. J. Quantum. Chem., 2018, 118, e25664.