TY - JOUR
T1 - Iridium(III) Phosphors–Bearing Functional 9-Phenyl-7,9-dihydro-8H-purin-8-ylidene Chelates and Blue Hyperphosphorescent OLED Devices
AU - Jin, Jibiao
AU - Zhu, Zelin
AU - Yan, Jie
AU - Zhou, Xiuwen
AU - Cao, Chen
AU - Chou, Pi-Tai
AU - Zhang, Ye-Xin
AU - Zheng, Zhong
AU - Lee, Chun-Sing
AU - Chi, Yun
PY - 2022/7
Y1 - 2022/7
N2 - Herein, a series of blue-emitting Ir(III) phosphors is reported based on the cyclometalating N-heterocyclic carbenes (NHCs), in which the typical benzimidazolylidene entity is now replaced by a new 7,9-dihydro-8H-purin-8-ylidene unit. The two extra-nitrogen atoms of benzimidazolylidene entity that are successfully fined turn the emission to the true-blue region. As the proof of concept, both experimental measurement and theoretical calculation of these emitters are conducted, revealing high photoluminescence quantum yields up to 92%, peak maximum located in the region 420–490 nm, and radiative lifetime lower than 1 μs, depending on their stereochemical configuration (i.e., meridional or facial), together with distinctive phenyl cyclometalating appendage. Their photophysical characteristics are among the best of carbene-based Ir(III) blue phosphors. Blue phosphorescent organic light-emitting diode (OLED) using one representative derivative m-2tBu as sole dopant emitter achieves a high external quantum efficiency (EQE) up to 17.0%, and a small efficiency roll-off of 16% at 1000 cd m−2. Furthermore, a true-blue hyperphosphorescent OLED with 25 wt% of m-2tBu as sensitizer and 2 wt% of N7,N7,N13,N13,5,9,11,15-octaphenyl-5,9,11,15-tetrahydro-5,9,11,15-tetraaza-19b,20b-diboradinaphtho[3,2,1-de:1′,2′,3′-jk]pentacene-7,13-diamine (ν-DABNA) as emitter is also fabricated, giving excellent performance with maximum EQE up to 22.0% and Commission Internationale de l’Éclairage (CIE)xy coordinates of (0.120, 0.155).
AB - Herein, a series of blue-emitting Ir(III) phosphors is reported based on the cyclometalating N-heterocyclic carbenes (NHCs), in which the typical benzimidazolylidene entity is now replaced by a new 7,9-dihydro-8H-purin-8-ylidene unit. The two extra-nitrogen atoms of benzimidazolylidene entity that are successfully fined turn the emission to the true-blue region. As the proof of concept, both experimental measurement and theoretical calculation of these emitters are conducted, revealing high photoluminescence quantum yields up to 92%, peak maximum located in the region 420–490 nm, and radiative lifetime lower than 1 μs, depending on their stereochemical configuration (i.e., meridional or facial), together with distinctive phenyl cyclometalating appendage. Their photophysical characteristics are among the best of carbene-based Ir(III) blue phosphors. Blue phosphorescent organic light-emitting diode (OLED) using one representative derivative m-2tBu as sole dopant emitter achieves a high external quantum efficiency (EQE) up to 17.0%, and a small efficiency roll-off of 16% at 1000 cd m−2. Furthermore, a true-blue hyperphosphorescent OLED with 25 wt% of m-2tBu as sensitizer and 2 wt% of N7,N7,N13,N13,5,9,11,15-octaphenyl-5,9,11,15-tetrahydro-5,9,11,15-tetraaza-19b,20b-diboradinaphtho[3,2,1-de:1′,2′,3′-jk]pentacene-7,13-diamine (ν-DABNA) as emitter is also fabricated, giving excellent performance with maximum EQE up to 22.0% and Commission Internationale de l’Éclairage (CIE)xy coordinates of (0.120, 0.155).
KW - blue
KW - carbine
KW - cyclometalate
KW - iridium
KW - organic light emitting diodes
KW - thermally activated delayed fluorescence
U2 - 10.1002/adpr.202100381
DO - 10.1002/adpr.202100381
M3 - RGC 21 - Publication in refereed journal
SN - 2699-9293
VL - 3
JO - Advanced Photonics Research
JF - Advanced Photonics Research
IS - 7
M1 - 2100381
ER -