Solubilised bright blue-emitting iridium complexes for solution processed OLEDs

Combining a sterically bulky, electron-deficient 2-(2,4-difluorophenyl)-4-(2,4,6-trimethylphenyl) pyridine (dFMesppy) cyclometalating C boolean AND N ligand with an electron rich, highly rigidified 1,1'-(alpha,alpha'-o-xylylene)-2,2'-biimidazole (o-xylbiim) N boolean AND N ligand gives an iridium complex, [Ir(dFMesppy)(2)(o-xylbiim)](PF6), that achieves extraordinarily bright blue emission (Phi(PL) = 90%; lambda(max) = 459 nm in MeCN) for a cationic iridium complex. This complex is compared with two reference complexes bearing 4,4'-di-tert-butyl-2,2'-bipyridine, and solution-processed organic light emitting diodes (OLEDs) have been fabricated from these materials.