Homoleptic Ir_((III))based carbene complexes are known to be the most promising emitters of future blue OLED devices.To provide the proof-of-concept,we designed a series of functional di-CF_(3)-functionalized benzo[d]...Homoleptic Ir_((III))based carbene complexes are known to be the most promising emitters of future blue OLED devices.To provide the proof-of-concept,we designed a series of functional di-CF_(3)-functionalized benzo[d]imidazol-3-ium pro-chelates,which could afford single product emitters after proper modification.For benzoimidazol-2-ylidene with an N-methyl substituent,selective formation of the product can be achieved by introduction of t-butylphenyl for the phenyl group,as shown by shifting the product from mixed m-Ir(dfp)_(3)and f-Ir(dfp)_(3)to the single isomer f-Ir(dfpb)_(3).Alternatively,for di-N-aryl substituted carbene chelates,the steric encumbrance imposed between the ortho-CF_(3)group and the adjacent N-aryl substituent redirects the cyclometalation to the other N-aryl substituent,leading to the formation of one single product,e.g.,f-Ir(tBpp)_(3)and f-Ir(ptBp)_(3).Moreover,the doped OLED based on f-Ir(tBpp)_(3)delivered true-blue emission centered at 457 nm and a maximum EQE of 15.6%.Furthermore,upon addition of terminal emittersν-DABNA and t-DABNA,the respective hyper^(-)OLEDs exhibited narrowband blue emission with a maximum EQE of 18.9%at 474 nm and 18.1%at 462 nm,respectively.These highlighted the potential of these Ir_((III))emitters in the fabrication of blue OLEDs.展开更多
基金supported by funding from the Research Grant Council(CityU 11304221 and CityU 11312722)the City University of Hong Kong,Hong Kong SAR。
文摘Homoleptic Ir_((III))based carbene complexes are known to be the most promising emitters of future blue OLED devices.To provide the proof-of-concept,we designed a series of functional di-CF_(3)-functionalized benzo[d]imidazol-3-ium pro-chelates,which could afford single product emitters after proper modification.For benzoimidazol-2-ylidene with an N-methyl substituent,selective formation of the product can be achieved by introduction of t-butylphenyl for the phenyl group,as shown by shifting the product from mixed m-Ir(dfp)_(3)and f-Ir(dfp)_(3)to the single isomer f-Ir(dfpb)_(3).Alternatively,for di-N-aryl substituted carbene chelates,the steric encumbrance imposed between the ortho-CF_(3)group and the adjacent N-aryl substituent redirects the cyclometalation to the other N-aryl substituent,leading to the formation of one single product,e.g.,f-Ir(tBpp)_(3)and f-Ir(ptBp)_(3).Moreover,the doped OLED based on f-Ir(tBpp)_(3)delivered true-blue emission centered at 457 nm and a maximum EQE of 15.6%.Furthermore,upon addition of terminal emittersν-DABNA and t-DABNA,the respective hyper^(-)OLEDs exhibited narrowband blue emission with a maximum EQE of 18.9%at 474 nm and 18.1%at 462 nm,respectively.These highlighted the potential of these Ir_((III))emitters in the fabrication of blue OLEDs.
