Blue-to-green electrophosphorescence of iridium-based cyclometallated materials

Mak, Chris S. K.; Hayer, Anna; Pascu, Sofia I.; Watkins, Scott E.; Holmes, Andrew B.; Köhler, Anna; Friend, Richard H.

doi:10.1039/b508695g

Cited by 104 publications

(73 citation statements)

References 22 publications

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“…[15,28] Similarly, Holmes and Friend finetuned electroluminescence in the green-to-blue regime through synthetic modifications to the chromophore and, more importantly, improved the operational lifetime of the devices through the use of more stable (i.e., less labile) ancillary ligands. [50] Neutral iridiumA C H T U N G T R E N N U N G (III) complexes have spurred tremendous interest (beyond the scope of this manu- This matrix is sandwiched between hole-(e.g., a-NPD) and electron-injecting (e.g., Alq 3 , q= 8-hydroxyquinoline) layers as well as a hole blocking layer (e.g., BCP) and capped with a low work-function cathode (e.g., LiF/Al) and a transparent anode (e.g., ITO). b) Single-layer device geometry in which a cationic iridiumA C H T U N G T R E N N U N G (III) chromophore is spin-coated on an ITO substrate and capped with a gold electrode.…”

Section: Oled Applicationsmentioning

confidence: 99%

Synthetically Tailored Excited States: Phosphorescent, Cyclometalated Iridium(III) Complexes and Their Applications

Lowry

Bernhard

2006

Chemistry A European J

739

562

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Phosphorescent iridium(III) complexes are being widely explored for their utility in diverse photophysical applications. The performance of these materials in such roles depends heavily on their excited-state properties, which can be tuned through ligand and substituent effects. This concept article focuses on methods for synthetically tailoring the properties of bis-cyclometalated iridium(III) materials, and explores the factors governing the nature of their lowest excited state.

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Section: Oled Applicationsmentioning

confidence: 99%

Synthetically Tailored Excited States: Phosphorescent, Cyclometalated Iridium(III) Complexes and Their Applications

Lowry

Bernhard

2006

Chemistry A European J

739

562

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“…When an octyl chain is introduced at the 4-position of the pyridyl group in L 3, the resulting chelate ligand can be used to prepare analogous octyl-substituted iridium complexes for PLEDs with PVK blends. [68] The maximum brightness is 110 cd m À2 at 18 V, and the luminous efficiency at 100 cd m À2 is 0.06 cd A…”

Section: à2mentioning

confidence: 99%

Phosphorescent Dyes for Organic Light‐Emitting Diodes

Chou

Chi

2006

Chemistry A European J

767

396

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This article presents general concepts that have guided important developments in our recent research progress regarding room-temperature phosphorescent dyes and their potential applications. We first elaborate the theoretical background for emissive metal complexes and the strategic design of the chelating C-linked 2-pyridylazolate ligands, followed by their feasibility in functionalization and modification in an aim to fine-tune the chemical and photophysical properties. Subsequently, incorporation of 2-pyridylazolate chromophores is illustrated in the synthesis of the highly emissive, charge-neutral Os, Ru, Ir, and Pt complexes. Insights into their photophysical properties are gained from spectroscopy, relaxation dynamics, and theoretical approaches, from which the lowest-lying excited states, competitive radiative decay, and radiationless processes are then analyzed in detail. In view of applications, their potentials for OLEDs have been evaluated. The results, in combination with the fundamental basis, give a conceptual design contributed to the future advances in the field of OLEDs.

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“…Given that iridium(III) complexes have given rise to efficient and long-lived red and green emissive OLED materials much of the research is now focusing on iridium-(III)-based complexes for blue emission. [1][2][3][4][5][6][7][8][9][10][11][12] The commonest approach toward complexes that emit blue has been to tweak the electronic structure of the parent fac-tris(2-phenylpyridyl)iridium(III) complex. [6][7][8][9][10] By adding fluorine atoms to the phenyl ring ortho and para to the pyridyl moiety it is possible to shift the emission from green to a light blue.…”

Section: Introductionmentioning

confidence: 99%

Solution‐Processible Phosphorescent Blue Dendrimers Based on Biphenyl‐Dendrons and Fac‐tris(phenyltriazolyl)iridium(III) Cores

Bera

Harding

et al. 2008

Adv Funct Materials

106

123

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Solution‐processible saturated blue phosphorescence is an important goal for organic light‐emitting diodes (OLEDs). Fac‐tris(5‐aryltriazolyl)iridium(III) complexes can emit blue phosphorescence at room temperature. Mono‐ and doubly dendronized fac‐tris(1‐methyl‐5‐phenyl‐3‐n‐propyl‐1H‐[1,2,4]triazolyl)iridium(III) 1 and fac‐tris{1‐methyl‐5‐(4‐fluorophenyl)‐3‐n‐propyl‐1H‐[1,2,4]triazolyl}iridium(III) 4 with first generation biphenyl‐based dendrons were prepared. The dendrimers emitted blue light at room temperature and could be solution processed to form thin films. The doubly dendronized 3 had a film photoluminescence quantum yield of 67% and Commission Internationale de l'Eclairage (CIE) coordinates of (0.17, 0.33). OLEDs comprised of a neat film of dendrimer 3 and an electron transport layer achieved a brightness of 142 cd m−2 at 3.8 V with an external quantum efficiency of 7.9%, and CIE coordinates of (0.18, 0.35). Attachment of the fluorine atom to the emissive core had the effect of moving the luminescence to shorter wavelengths but also quenched the luminescence of the mono‐ and doubly dendronized dendrimers.

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Blue-to-green electrophosphorescence of iridium-based cyclometallated materials

Cited by 104 publications

References 22 publications

Synthetically Tailored Excited States: Phosphorescent, Cyclometalated Iridium(III) Complexes and Their Applications

Synthetically Tailored Excited States: Phosphorescent, Cyclometalated Iridium(III) Complexes and Their Applications

Phosphorescent Dyes for Organic Light‐Emitting Diodes

Solution‐Processible Phosphorescent Blue Dendrimers Based on Biphenyl‐Dendrons and Fac‐tris(phenyltriazolyl)iridium(III) Cores

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