Application of the five-membered ring blue light-emitting iridium products of cyclometalation reactions as OLEDs

Abstract

Organic light-emitting diodes (OLEDs) are manufactured primarily by synthesizing five-membered ring products using cyclometalation reactions. Highly photoluminescent quantum efficient emitters are primarily prepared by utilizing the following five types of iridium compounds: 1. N-Heterocyclic carbene compounds such as phenylimidazolinate-type carbene compounds and 2-phenylpyridine N-heterocyclic carbene compounds; 2. NCN-tridentate type compounds; 3. Polycyclic compounds, such as phenanthro-imidazole and fluorenylpyrazole compounds; 4. Heterocyclic compounds, such as 2-phenylpyridines, 2-phenylpyridine fluorinated compounds, phenyl-imidazole, -pyrazole, and -triazole compounds, 2,3⿲-bispyridines and phosphites; and 5. High-molecular-weight cyclometalated compounds such as the dendrimers of phenyltriazoles.In particular, the presence of a high field ligand such as an N-heterocyclic carbene in these compounds facilitates high energy emission, which results in the desired blue-colored light required for OLED applications.