Highly Efficient Blue‐Emitting Iridium(III) Carbene Complexes and Phosphorescent OLEDs

Chang, Chiung-Fang; Cheng, Yi‐Ming; Chi, Yun; Chiu, Yuan-Chieh; Lin, Chao-Chen; Lee, Gene‐Hsiang; Chou, Pi‐Tai; Chen, Chung-Chia; Chang, Ching S.; Wu, Chung‐Chih

doi:10.1002/ange.200800748

Cited by 72 publications

(28 citation statements)

References 45 publications

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“…Phosphorescent materials are particularly desirable over fluorescent emitters due to their potential to harvest both singlet and triplet excitations generated in a device. [1,2] However, the development of efficient deep-blue phosphorescent emitters, which are required for full-colour OLED displays, [3][4][5][6] has remained a persistent problem since the field was established with the discovery of the green phosphorescent complex factris(2-phenylpyridyl)iridium(III) [Ir(ppy) 3 ; Figure 1 and Table 1]. [7] Fac-tris(1-methyl-5-phenyl-3-n-propyl- [1,2,4]…”

Section: Introductionmentioning

confidence: 99%

Spin–Orbit Coupling in Phosphorescent Iridium(III) Complexes

2011

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We study the excited states of two iridium(III) complexes with potential applications in organic light-emitting diodes: fac-tris(2-phenylpyridyl)iridium(III) [Ir(ppy)(3)] and fac-tris(1-methyl-5-phenyl-3-n-propyl-[1,2,4]triazolyl)iridium(III) [Ir(ptz)(3)]. Herein we report calculations of the excited states of these complexes from time-dependent density functional theory (TDDFT) with the zeroth-order regular approximation (ZORA). We show that results from the one-component formulation of ZORA, with spin-orbit coupling included perturbatively, accurately reproduce both the results of the two-component calculations and previously published experimental absorption spectra of the complexes. We are able to trace the effects of both scalar relativistic correction and spin-orbit coupling on the low-energy excitations and radiative lifetimes of these complexes. In particular, we show that there is an indirect relativistic stabilisation of the metal-to-ligand charge transfer (MLCT) states. This is important because it means that indirect relativistic effects increase the degree to which SOC can hybridise singlet and triplet states and hence plays an important role in determining the optical properties of these complexes. We find that these two compounds are remarkably similar in these respects, despite Ir(ppy)(3) and Ir(ptz)(3) emitting green and blue light respectively. However, we predict that these two complexes will show marked differences in their magnetic circular dichroism (MCD) spectra.

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Section: Introductionmentioning

confidence: 99%

Spin–Orbit Coupling in Phosphorescent Iridium(III) Complexes

2011

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“…The carbene derivatives, [(fbmb) 2 Ir(bptz)] (fbmb = 1-(4-fluorobenzyl)-3-methylbenzimidazolium, bptz = 4-tert-butyl-2-(5-(trifluoromethyl)-1, 2, 4-triazol-3-yl)pyridine) and [(dfbmb) 2Ir(fptz)] (dfbmb = 1-(2, 4-difluorobenzyl)-3-methylben-zimidazolium, fptz = 2-(5-(trifluoromethyl)-1, 2,4-triazol-3-yl) pyridine) exhibit deep blue PL emission peak at 460 and 458 nm, respectively [221].Their phosphorescence quantum yield are much higher than phenylimidazolebased [(fpmb)2Ir(bptz)] (fpmb = 1-(4-fluorophenyl)-3-methylbenzoimidazolium, bptz = 4-tert-butyl-2-(5-(trifluoromethyl)-1, 2, 4-triazol-3-yl)pyridine) because of distinctively low nonradiative decay constant of the benzylimidazole-based dopant materials. The best performing (dfbmb) 2 Ir(fptz)-doped PHOLED shows a maximum quantum efficiency of 6 % with deep blue color coordinates of (0.16, 0.13).…”

Section: Blue Phosphorescent Materialsmentioning

confidence: 99%

“…Moreover, Ir(pmb) 3 OLEDs exhibit serious efficiency roll-off: EQE decreases to 2.3 % at a current density of 10 mA/cm 2 and EQE is as low as 0.5 % at a current density of 100 mA/cm 2 . Another carbene-containing blue phosphorescence material is (dfbmb) 2 Ir(tptz) [221] and it has a much better quantum yield of *0.73 but somewhat worse in color coordinates of (0.16, 0.13). EQE of (dfbmb) 2 Ir (tptz) OLED can reach 6.0 % but efficiency roll-off is intense.…”

Section: Blue Phosphorescent Materialsmentioning

confidence: 99%

Organic Semiconductor Electroluminescent Materials

2015

Lecture Notes in Chemistry

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This chapter reviews the important progress made on small molecule electroluminescent materials used in organic light-emitting diode (OLED). In many cases we describe not only the material structures but also the properties associated with these materials, such as energy level, absorption and photoluminescence (PL) peaks, PL quantum yield, exciton life time, and so on. The performances of related devices are covered as well if they are available.

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“…Moreover,palladacycles are also emerging as the most versatile candidatesf or luminescent devices [2,[9][10]. NHCs have attractedi ncreasingi nteresta sa ncillary ligandst hato penedn ew avanues for the design of emitting materials, because of their excellent color purity and high stability [1,[11][12]. Aview of the molecular structure of the title compound is given in the figure.…”

mentioning

confidence: 99%

Crystal structure of [2-(4-bromophenyl)pyridine-κ2C,N)bromo[1,3-bis- (4-methylphenyl)imidazol-2-ylidene-κC)] palladium(II), C28H23Br2N3Pd

Song

Wang

2015

Zeitschrift Für Kristallographie - New Crystal Structures

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Source of materialThetitle compound was obtained as aside-product from reaction the corresponding palladacyclic dimero f2 -(4-bromophenyl)-pyridine and 1,3-bis(4-methylphenyl)imidazolium chloride as described in literature [1] and recrystallized from dichloromethane/petroleum ether solution at room temperature. DiscussionPalladacycles are one of themost developed and studied classes of organo-palladium derivatives, whicha re widely appliedi n couplingreactionsaseffective catalysts [2][3][4].Among them,the N-heterocyclic carbenes (NHCs) adducts combine the stability induced by the presence of ap alladacycle framework with the high activity commonly associated with NHCs, and were far more active than the corresponding dimeric palladacycles [5][6][7][8]. Moreover,palladacycles are also emerging as the most versatile candidatesf or luminescent devices [2,[9][10]. NHCs have attractedi ncreasingi nteresta sa ncillary ligandst hato penedn ew avanues for the design of emitting materials, because of their excellent color purity and high stability [1,[11][12]. Aview of the molecular structure of the title compound is given in the figure. The Pd atom is in aslightly distorted square planar environment bonded to the bromido ligand, the C12 atom of NHC-type ligand, the nitrogen atom and the Catom of the benzyl-pyridyl ligand. Thebicyclicsystemformedbythe palladacycle and the pyridyl ring is approximatelyc oplanar (dihedral angle of 5.6°). The imidazole ring plane of the NHC-type ligand is almost perpendicular to the square plane formedbythe Pd(II) center and the coordinated atoms( dihedral angles of 74.4°). In this type of arrangement the N-substituents of the NHC ligand reduce the steric interaction with the benzyl-pyridyl ligand. The Pd-C carb , Pd-N bond lengths of the title complex are similar to those of the corresponding carbene adduct containing the chlorine [1], while Pd-Br bond length [2.5255(7) Å] is obviously longer than Pd-Cl bond length [2.4205(7) Å] [1].

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Highly Efficient Blue‐Emitting Iridium(III) Carbene Complexes and Phosphorescent OLEDs

Cited by 72 publications

References 45 publications

Spin–Orbit Coupling in Phosphorescent Iridium(III) Complexes

Spin–Orbit Coupling in Phosphorescent Iridium(III) Complexes

Organic Semiconductor Electroluminescent Materials

Crystal structure of [2-(4-bromophenyl)pyridine-κ2C,N)bromo[1,3-bis- (4-methylphenyl)imidazol-2-ylidene-κC)] palladium(II), C28H23Br2N3Pd

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