Blue-emitting cationic iridium(<scp>iii</scp>) complexes featuring pyridylpyrimidine ligands and their use in sky-blue electroluminescent devices

Henwood, Adam Francis; Pal, Amlan K.; Cordes, David B.; Slawin, Alexandra M. Z.; Rees, Thomas W.; Momblona, Cristina; Babaei, Azin; Pertegás, Antonio; Ortı́, Enrique; Bolink, Henk J.; Baranoff, Etienne; Zysman‐Colman, Eli

doi:10.1039/c7tc03110f

Cited by 43 publications

(32 citation statements)

References 59 publications

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“…It is known that frontier molecular orbitals (FMO) of complex ground state S 0 are related to its spectral properties [86]. Emission color of iridium(III) complexes can be adjusted by changing their HOMO-LUMO bandgap, which can be achieved on the course of ligand functionalization with electron-donating and electronwithdrawing substituents [86], and values of HOMO-LUMO gaps predicted for Ir(III) complexes by DFT methods showed surprisingly good correlation with the experimentally recorded values of energies of emitted photons even in the case of phosphorescence, see for example [21,22,[83][84][85][87][88][89][90]. Contour plots of frontier orbitals of both [Ir(bzq) 3 ] isomers are depicted in Fig.…”

Section: Frontier Molecular Orbitals Analysismentioning

confidence: 80%

Quantum-chemical studies of homoleptic iridium(III) complexes in OLEDs: fac versus mer isomers

et al. 2019

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A series of facial fac-[Ir(5-R-bzq) 3 ] and meridional mer-[Ir(5-R-bzq) 3 ] Ir(III) complexes bearing benzo[h]quinoline-based ligands have been studied with the help of density functional theory (DFT) methods. A detailed electronic structure comparison of the two isomers has been addressed to point out the differences in their stability and photophysical properties. An influence of substituent impact on optical and electronic properties of Ir(III) homoleptic complexes was also explored by introducing into the cyclometalated ligands substituents characterized with different electronic properties, e.g., R = H, F, OPh, NMe 2 , C 6 F 5 , and p-C 6 H 4-NPh 2. The results herein show that fac and mer isomers exhibit remarkable differences in stability and photophysical properties. The introduction of different functional groups into bzq ligands, despite very similar geometrical structures, significantly affected HOMO and LUMO energy levels and energy gaps of the examined Ir(III) complexes.

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Section: Frontier Molecular Orbitals Analysismentioning

confidence: 80%

Quantum-chemical studies of homoleptic iridium(III) complexes in OLEDs: fac versus mer isomers

et al. 2019

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“…Besides, deeper investigation is also imperative referring the underlying sublimation mechanism, for instance, how the cations and anions ultimately separate by heat, travel under vacuum and finally deposit onto the substrates during device preparation. Moreover, sublimable cationic iridium(III) complexes also show great promise in other organic semiconductors, since their solution‐processable analogues have been widely used in light‐emitting electrochemical cells (LEECs) and optical devices for data record, storage and security . Therefore we believe this paper will attract more research interest and stimulate greater progress in the future.…”

Section: Discussionmentioning

confidence: 98%

Recent Progress in Sublimable Cationic Iridium(III) Complexes for Organic Light‐Emitting Diodes

Duan

2018

The Chemical Record

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Sublimable cationic iridium(III) complexes consisting of light-emitting coordinated iridium(III) cations and nonluminous negative counter-ions, show excellent photophysical properties, superior electrochemical behaviors and high thermal stabilities, therefore have emerged as a new library of phosphorescent materials for various organic optoelectronic devices.Here we summarize and highlight the recent progress in sublimable cationic iridium(III) complexes, regarding the material design strategies, synthetic routes, photoluminescent characteristics in both solutions and neat films, together with the current utilization in organic lightemitting diodes based on the emissive material layers fabricated by vacuum evaporation deposition. Finally, we present a brief outlook thereon, indicating the great promise and brilliant application prospect of sublimable cationic iridium(III) complexes in future flat-panel display and solid-state lighting technology.

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“…5−9 Among transition-metal complexes, iridium(III) complexes proved to be the most efficient for applications in single-layer LEEC devices. 10−12 But, even though green and yellow emitting complexes have been extensively studied, the literature reporting on red emitting iridium complexes and their applications in LEEC devices is still scanty. 13−18…”

Section: Introductionmentioning

confidence: 99%

Luminescent cis-Iridium(III) Complex Based on a Bis(6,7-dimethoxy-3,4-dihydroisoquinoline) Platform Featuring an Unusual cis Orientation of the C^∧N Ligands: From a Theoretical Approach to a Deep Red LEEC Device

et al. 2019

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By pursuing the strategy of manipulating natural compounds to obtain functional materials, in this work, we report on the synthesis and characterization of a luminescent cationic iridium complex ( cis - 1 ), designed starting from the catecholic neurotransmitter dopamine, exhibiting the unusual cis arrangement of the C ∧ N ligands. Through an integrated experimental and theoretical approach, it was possible to delineate the optoelectronic properties of cis - 1 . In detail, (a) a series of absorption maxima in the range 300–400 nm was assigned to metal-to-ligand charge transfer and weak and broad absorption maxima at longer wavelengths (400–500 nm) were ascribable to spin-forbidden transitions with a mixed character; (b) there was an intense red phosphorescence with emission set in the range 580–710 nm; and (c) a highest occupied molecular orbital was mainly localized on the metal and the 2-phenylpiridine ligand and a lowest unoccupied molecular orbital was localized on the N ∧ N ligand, with a Δ H–L set at 2.20 eV. This investigation allowed the design of light-emitting electrochemical cell (LEEC) devices endowed with good performance. The poor literature reporting on the use of cis -iridium(III) complexes in LEECs prompted us to investigate the role played by the selected cathode and the thickness of the emitting layer, as well as the doping effect exerted by ionic liquids on the performance of the devices. All the devices exhibited a deep red emission, in some cases, quite near the pure color (devices #1, #4, and #8), expanding the panorama of the iridium-based red-to-near-infrared LEEC devices. The characteristics of the devices, such as the brightness reaching values of 162 cd/m 2 for device #7, suggested that the performances of cis - 1 are comparable to those of trans isomers, opening new perspective toward designing a new set of luminescent materials for optoelectronic devices.

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Blue-emitting cationic iridium(iii) complexes featuring pyridylpyrimidine ligands and their use in sky-blue electroluminescent devices

Abstract: The synthesis, structural and photophysical characterisation, and LEEC devices of four novel, cationic iridium(iii) complexes are reported.

Cited by 43 publications

References 59 publications

Quantum-chemical studies of homoleptic iridium(III) complexes in OLEDs: fac versus mer isomers

Quantum-chemical studies of homoleptic iridium(III) complexes in OLEDs: fac versus mer isomers

Recent Progress in Sublimable Cationic Iridium(III) Complexes for Organic Light‐Emitting Diodes

Luminescent cis-Iridium(III) Complex Based on a Bis(6,7-dimethoxy-3,4-dihydroisoquinoline) Platform Featuring an Unusual cis Orientation of the C^∧N Ligands: From a Theoretical Approach to a Deep Red LEEC Device

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Blue-emitting cationic iridium(iii) complexes featuring pyridylpyrimidine ligands and their use in sky-blue electroluminescent devices

Abstract: The synthesis, structural and photophysical characterisation, and LEEC devices of four novel, cationic iridium(iii) complexes are reported.

Cited by 43 publications

References 59 publications

Quantum-chemical studies of homoleptic iridium(III) complexes in OLEDs: fac versus mer isomers

Quantum-chemical studies of homoleptic iridium(III) complexes in OLEDs: fac versus mer isomers

Recent Progress in Sublimable Cationic Iridium(III) Complexes for Organic Light‐Emitting Diodes

Luminescent cis-Iridium(III) Complex Based on a Bis(6,7-dimethoxy-3,4-dihydroisoquinoline) Platform Featuring an Unusual cis Orientation of the C∧N Ligands: From a Theoretical Approach to a Deep Red LEEC Device

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Luminescent cis-Iridium(III) Complex Based on a Bis(6,7-dimethoxy-3,4-dihydroisoquinoline) Platform Featuring an Unusual cis Orientation of the C^∧N Ligands: From a Theoretical Approach to a Deep Red LEEC Device