Bright and stable light-emitting electrochemical cells based on an intramolecularly π-stacked, 2-naphthyl-substituted iridium complex

Schneider, Gabriel E.; Pertegás, Antonio; Constable, Edwin C.; Housecroft, Catherine E.; Hostettler, Nik; Morris, Collin D.; Zampese, Jennifer A.; Bolink, Henk J.; Junquera‐Hernández, José M.; Ortı́, Enrique; Sessolo, Michele

doi:10.1039/c4tc01171f

Cited by 38 publications

(29 citation statements)

References 38 publications

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“…The ancillary N^N ligands show N−Ir−N bite angles of 76.1(1)° (for tbz in [4][PF 6 ]) and 75.9(1)° (for Metbz in [5][PF 6 ]), in agreement with those previously reported for five-membered iridacycles in similar complexes. 46,47 The cyclometalated C^N ligands have also standard values (~80°) for the C−Ir−N bite angles. In both compounds, the 3D crystal architecture is built on the foundation of hydrogen bonding contacts and anion-π interactions in which the PF 6 − anions occupy a central position ( Figure S4).…”

Section: Results and Discussion Synthesis And Characterizationmentioning

confidence: 99%

Highly Stable and Efficient Light-Emitting Electrochemical Cells Based on Cationic Iridium Complexes Bearing Arylazole Ancillary Ligands

et al. 2017

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A series of bis-cyclometalated iridium(III) complexes of general formula [Ir(ppy)2(N∧N)][PF6] (ppy– = 2-phenylpyridinate; N∧N = 2-(1H-imidazol-2-yl)pyridine (1), 2-(2-pyridyl)benzimidazole (2), 1-methyl-2-pyridin-2-yl-1H-benzimidazole (3), 2-(4′-thiazolyl)benzimidazole (4), 1-methyl-2-(4′-thiazolyl)benzimidazole (5)) is reported, and their use as electroluminescent materials in light-emitting electrochemical cell (LEC) devices is investigated. [2][PF6] and [3][PF6] are orange emitters with intense unstructured emission around 590 nm in acetonitrile solution. [1][PF6], [4][PF6], and [5][PF6] are green weak emitters with structured emission bands peaking around 500 nm. The different photophysical properties are due to the effect that the chemical structure of the ancillary ligand has on the nature of the emitting triplet state. Whereas the benzimidazole unit stabilizes the LUMO and gives rise to a 3MLCT/3LLCT emitting triplet in [2][PF6] and [3][PF6], the presence of the thiazolyl ring produces the opposite effect in [4][PF6] and [5][PF6] and the emitting state has a predominant 3LC character. Complexes with 3MLCT/3LLCT emitting triplets give rise to LEC devices with luminance values 1 order higher than those of complexes with 3LC emitting states. Protecting the imidazole N–H bond with a methyl group, as in complexes [3][PF6] and [5][PF6], shows that the emissive properties become more stable. [3][PF6] leads to outstanding LECs with simultaneously high luminance (904 cd m–2), efficiency (9.15 cd A–1), and stability (lifetime over 2500 h).

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Section: Results and Discussion Synthesis And Characterizationmentioning

confidence: 99%

Highly Stable and Efficient Light-Emitting Electrochemical Cells Based on Cationic Iridium Complexes Bearing Arylazole Ancillary Ligands

et al. 2017

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“…Going from dpp to ligands 1-4 involves a change from a rigid phen backbone to a bpy unit that, even when chelated, can undergo signicant torsional deformation. 33 We suggest that this is a contributing factor towards the sensitivity of [Cu(2)(4)] + towards iodide ion. Finally, while both [Cu(1)(4)] + and [Cu(2)(3)] + contain identical local copper(I) coordination environments (Fig.…”

Section: Model Dyes With Anchoring Ligandmentioning

confidence: 97%

Copper(i)-based dye-sensitized solar cells with sterically demanding anchoring ligands: bigger is not always better

et al. 2015

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The synthesis and characterization of ((6,6 0 -diphenyl-[2,2 0 -bipyridine]-4,4 0 -diyl)bis(4,1-phenylene)) bis(phosphonic acid), 2, are described. Compound 2 has been incorporated as an anchoring ligand in copper(I)-containing dyes in n-type dye-sensitized solar cells (DSCs), combined with 2,2 0 -bipyridine (bpy), 6-methyl-2,2 0 -bipyridine (6-Mebpy), 6,6 0 -dimethyl-2,2 0 -bipyridine (6,6 0 -Me 2 bpy), 4,4 0 -di(4-bromophenyl)-6,6 0 -dimethyl-2,2 0 -bipyridine (3) or 4,4 0 -di(4-bromophenyl)-6,6 0 -diphenyl-2,2 0 -bipyridine (4) as ancillary ligands (L ancillary ). Dyes were assembled on mesoporous TiO 2 using an on-surface assembly strategy which relies on ligand exchange between surface-anchored L anchor and [Cu(L ancillary ) 2 ] + ; 1 H NMR spectroscopy was used to confirm that the bulky phenyl substituents did not hinder ligand exchange. Comparison of values of the open-circuit voltages (V OC ), short-circuit current densities (J SC ) and external quantum efficiency (EQE) spectra for DSCs with model dyes [Cu(2)(bpy)] + , [Cu(2)(6-Mebpy)] + and [Cu(2)(6,6 0 -Me 2 bpy)] + confirm that methyl-substituents in L ancillary are beneficial. Performance data for DSCs with dyes [Cu(1)(3)] + , [Cu(1)(4)] + , [Cu(2)(3)] + and [Cu(2)(4)] + where 1 is the anchor ((6,6 0 -dimethyl-[2,2 0 -bipyridine]-4,4 0 -diyl)bis(4,1-phenylene))bis(phosphonic acid) show that dyes with anchor 2 (phenyl substituents in the 6-and 6 0 -positions) give relative conversion efficiencies #10% with respect to standard dye N719 set at h ¼ 100%; this compares with relative efficiencies of up to 34.5% for the dyes [Cu(1)(3)] + and [Cu(1)(4)] + . The performance of [Cu(2)(3)] + can be improved by the addition of the co-adsorbant chenodeoxycholic acid. Although the phenyl (versus methyl) substituentslead to enhanced light absorption to lower energies, dyes with anchor 2 quickly bleach when exposed to the I À /I 3 À electrolyte; bleaching also occurs after soaking in solutions of LiI. The dye can be regenerated by treatment of a bleached electrode with L ancillary , or with [Cu(NCMe) 4 ] + followed by L ancillary .

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“…1 H and 13 C NMR data were consistent with the literature data. 25 ESI MS: m/z 305.0 [M + Na] + (base peak, calc. 305.1).…”

Section: -(Naphthalen-2-yl)-22'-bipyridinementioning

confidence: 99%

The effects of introducing sterically demanding aryl substituents in [Cu(N^N)(P^P)]⁺complexes

et al. 2017

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The syntheses and characterizations of six [Cu(N^N)(POP)][PF] and [Cu(N^N)(xantphos)][PF] compounds (POP = bis(2-(diphenylphosphino)phenyl)ether, xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene), in which N^N is a bpy ligand (1-Naphbpy, 2-Naphbpy, 1-Pyrbpy) bearing a sterically hindered 1-naphthyl, 2-naphthyl or 1-pyrenyl substituent in the 6-position, are reported. Single-crystal structure determinations of five complexes confirm a distorted tetrahedral environment for copper(i) and a preference for the N^N ligand to be oriented with the sterically-demanding aryl group being remote from the (CH)O unit of POP or the xanthene 'bowl' of xantphos. The angle between the ring planes of the bpy range from 5.8 to 26.0° and this is associated with interactions between the aryl unit and the phenyl substituents of the P^P ligand. In solution at room temperature, the complexes undergo dynamic behaviour which has been investigated using variable temperature 2D NMR spectroscopy. The [Cu(N^N)(xantphos)] complexes exist as a mixture of conformers which interconvert through inversion of the xanthene bowl-shaped unit; the preference for one conformer over the other is significantly changed on going from N^N = Phbpy to 1-Pyrbpy (Phbpy = 6-phenyl-2,2'-bipyridine). The electrochemical and photophysical properties of the [Cu(N^N)(POP)][PF] and [Cu(N^N)(xantphos)][PF] compounds are presented; the compounds are orange emitters but the introduction of the 1-naphthyl, 2-naphthyl or 1-pyrenyl substituents result in poor photoluminescence quantum yields.

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Bright and stable light-emitting electrochemical cells based on an intramolecularly π-stacked, 2-naphthyl-substituted iridium complex

Abstract: LECs incorporating [Ir(ppy)2(Naphbpy)][PF6] (Hppy = 2-phenylpyridine, Naphbpy = 6-(2-naphthyl)-2,2′-bipyridine) in the emissive layer show high luminance and exceptional stabilities.

Cited by 38 publications

References 38 publications

Highly Stable and Efficient Light-Emitting Electrochemical Cells Based on Cationic Iridium Complexes Bearing Arylazole Ancillary Ligands

Highly Stable and Efficient Light-Emitting Electrochemical Cells Based on Cationic Iridium Complexes Bearing Arylazole Ancillary Ligands

Copper(i)-based dye-sensitized solar cells with sterically demanding anchoring ligands: bigger is not always better

The effects of introducing sterically demanding aryl substituents in [Cu(N^N)(P^P)]⁺complexes

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Bright and stable light-emitting electrochemical cells based on an intramolecularly π-stacked, 2-naphthyl-substituted iridium complex

Abstract: LECs incorporating [Ir(ppy)2(Naphbpy)][PF6] (Hppy = 2-phenylpyridine, Naphbpy = 6-(2-naphthyl)-2,2′-bipyridine) in the emissive layer show high luminance and exceptional stabilities.

Cited by 38 publications

References 38 publications

Highly Stable and Efficient Light-Emitting Electrochemical Cells Based on Cationic Iridium Complexes Bearing Arylazole Ancillary Ligands

Highly Stable and Efficient Light-Emitting Electrochemical Cells Based on Cationic Iridium Complexes Bearing Arylazole Ancillary Ligands

Copper(i)-based dye-sensitized solar cells with sterically demanding anchoring ligands: bigger is not always better

The effects of introducing sterically demanding aryl substituents in [Cu(N^N)(P^P)]+complexes

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The effects of introducing sterically demanding aryl substituents in [Cu(N^N)(P^P)]⁺complexes