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Tris(5‐phenyl‐1 H ‐1,2,4‐triazolyl)iridium(III) Complex and Its Use in Blue Phosphorescent Organic Light‐Emitting Diodes to Provide an External Quantum Efficiency of up to 27.8%
Author(s) -
Ryu Chan Hee,
Lim Junseob,
Kim Moon Bae,
Lee Ji Hye,
Hwang Hyonseok,
Lee Jun Yeob,
Lee Kang Mun
Publication year - 2021
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.202001957
Subject(s) - phosphorescence , iridium , oled , materials science , quantum efficiency , phosphorescent organic light emitting diode , dopant , homoleptic , carbazole , photochemistry , doping , optoelectronics , nanotechnology , fluorescence , chemistry , catalysis , organic chemistry , optics , physics , metal , layer (electronics) , metallurgy
Although studies have investigated various N ‐heterocyclic‐based Ir(III)‐cyclometalates that exhibit high efficiency and electrochemical stability, blue‐phosphorescent Ir(III) complexes with further improved efficiency and blue‐emission purity are needed for use as emitters in organic light‐emitting diodes (OLEDs). Therefore, the preparation and comprehensive characterization of a phenyl‐1,2,4‐triazole‐based facial ‐homoleptic iridium(III) complex, TzIr (fac‐tris(1‐(2,6‐diisopropylphenyl)‐3‐methyl‐5‐phenyl‐1 H ‐1,2,4 triazolyl)iridium(III)) is herein described. The complex shows a definite blue‐emission band (λ em = 456 nm) in the solution and film states at ambient temperature. Moreover, this complex exhibits considerably high phosphorescent quantum efficiency (80%) and thermal stability ( T d5 = 362 °C). Multilayer phosphorescent OLEDs using TzIr as the emitter and 3,3‐di(9 H ‐carbazol‐9‐yl)biphenyl (mCBP)/ 9‐(3′‐(9 H ‐carbazol‐9‐yl)‐5‐cyano‐[1,1′‐biphenyl]‐3‐yl)‐9 H ‐carbazole‐3‐carbonitrile (CNmCBPCN) as the mixed host are fabricated. The devices exhibit outstanding performance, with a high external quantum efficiency (27.8%), current efficiency (38.7 cd A −1 ), and CIE y ( y coordinate value of the Commission Internationale de l'Eclairage color space) less than 0.18. The results of this study indicate that this novel 1,2,4‐triazole‐based dopant, TzIr , is a promising candidate for developing highly efficient blue‐phosphorescent emitters for use in OLEDs.