Naphthyridine-based iridium() complexes for green to red OLEDs with EQEs over 30% and low efficiency roll-off

Four new naphthyridine-based iridium( iii ) complexes, namely (dfpmp) 2 Ir(mmND) , (mtfmpp) 2 Ir(mmND) , (tfmptp) 2 Ir(mmND) , and (mtfmptp) 2 Ir(mmND) , were designed and synthesized. The complexes show tunable emission peak wavelengths from 521 nm to 600 nm with relatively high photoluminescence quantum yields (PLQYs) of 80-85% in CH 2 Cl 2 . Employing these emitters, all the organic light-emitting diodes (OLEDs) exhibit prominent performances with the maximum external quantum efficiency (EQE max ) exceeding 30%, and simultaneously the efficiency roll-off is extremely low. Of note, the double emissive layer OLED using (mtfmpp) 2 Ir(mmND) as the dopant achieves the optimal electroluminescence (EL) performances with an EQE max of 32.3% and an ultrahigh brightness of 242 548 cd m −2 . Four rigid naphthyridine-based iridium( iii ) complexes are developed with good electron mobility, high device efficiency and extremely low efficiency roll-off.