An iridium complex and a nitrogen-containing tridentate ligand are provided. The iridium complex is represented by below formula:wherein R1 and R1’ are each independently substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C6-C12 aryl, or -CmF2m+1, m is an integer of 0 to 3; R2 and R2’ are each independently hydrogen, substituted or unsubstituted C1-C12 alkyl, or substituted or unsubstituted C6-C12 aryl; p and p’ are each independently 0 or 1; R3, R3’, R4 and R4’ are each independently hydrogen, fluorine, substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted C1-C6 alkoxyl, or substituted or unsubstituted C6-C12 aryl; q and q’ are each independently an integer of 0 to 3; r and r’ are each independently an integer of 0 to 4; X1 to X7 are each independently carbon or nitrogen; A is -O-, -CH2-, or -CR2-, R is methyl, ethyl, or propyl; and a is 0 or 1. |