Finely-tuned heteroleptic phosphorescent Ir(III) complexes for CIEy < 0.2-based pure blue organic light-emitting diodes with external quantum efficiencies > 30%

Three pure blue phosphorescent Ir (III) complexes F5OFpt, F5MFpt and F5SiFpt with the amazing CIEy coordinate value<0.2 have been obtained by introducing different electron-donating groups (-OMe, -Me and -TMS) into the corresponding C^N ligands. Based on a well matched mixed host combination of mCBP and TSPO1, all the emitting systems achieve quite high maximum EQE > 30% with low efficiency roll-off and ideal blue color with the CIEy < 0.2.