Synthesis and Electroluminescence of Two Red Iridium Complexes

By introducing tetraphenylimidodiphosphinate (Htpip) as the ancillary ligand, two iridium complexes Ir (tfmpiq)(2)tpip and Jr (dfpiq)(2)tpip (dfpiq =2-(2,4-difluorophenyl)quinoline, tfmpiq =2-(4-(trifluoromethyl)phenyl) quinoline) have been synthesized. For the emission spectra in CH2Cl2 solution, the maximum peaks locate at 622 and 600 nm for Ir(tfmpiq)(2)tpip and Ir(dfpiq)(2)tpip with the quantum efficiencies of 15% and 17%, respectively. The HOMO/LUMO levels are calculated as -4.80/-2.58 and -4.73/-2.57 eV, respectively. Under electric field from 1150 to 1300 (V . cm(-1))(1/2), the electron mobilities in 60 nm Ir(tfmpiq)(2)tpip and Ir(dfpiq)(2)tpip layers are 6.61 similar to 8.49x 10(-6) cm(2).V-1.s(-1) and 6.08 similar to 6.61x10(-6) cm(2).V-1.s(-1), respectively. The devices with the structure of ITO/TAPC(60 nm)/Ir-complex (15wt%): CBP (50 nm)/TPBi(60 nm)/LiF(1 nm)/Al(100 nm) were fabricated. The device based on Ir(dfpiq)(2)tpip exhibited a luminance of 18 195 cd.m(-2) at a driving voltage of 12.0 V with a maximum current efficiency (eta(c)) of 4.71 cd.A(-1) and a maximum power efficiency (eta(p)) of 1.82 lm.W-1, respectively. While the device based on Ir(tfmpiq)(2)tpip exhibited a luminance of 14 676 cd.m(-2) at a driving voltage of 12.0 V with a maximum eta(c) of 3.47 cd.A(-1) and eta(p) of 1.51 lm.W-1, respectively.