| 1. |
- Elie, Margaux, et al.
(författare)
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Designing NHC-Copper(I) Dipyridylamine Complexes for Blue Light-Emitting Electrochemical Cells
- 2016
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 8:23, s. 14678-14691
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Tidskriftsartikel (refereegranskat)abstract
- This study presents the influence of various substituents on the photophysical features of heteroleptic copper(I) complexes bearing both N-heterocyclic carbene (NHC) and dipyridylamine (dpa = dipyridylamine skeleton corresponding to ligand L1) ligands. The luminescent properties have been compared to our recently reported archetypal blue emitting [Cu(IPr)(dpa)][PF6] complex. The choice of the substituents on both ligands has been guided to explore the effect of the electron donor/acceptor and "push-pull" on the emission wavelengths and photoluminescence quantum yields. A selection of the best candidates in terms of their photophysical features were applied for developing the first blue light emitting electrochemical cells (LECs) based on copper(I) complexes. The device analysis suggests that the main concern is the moderate redox stability of the complexes under high applied driving currents, leading to devices with moderate stabilities pointing to a proof-of-concept for further development. Nevertheless, under low applied driving currents the blue emission is stable, showing performance levels competitive to those reported for blue LECs baged on iridium(III) complexes. Overall, this work provides valuable guidelines to tackle the design of enhanced NHC copper complexes for lighting applications in the near future.
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| 2. |
- Elie, Margaux, et al.
(författare)
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Role of the Bridging Group in Bis-Pyridyl Ligands : Enhancing Both the Photo- and Electroluminescent Features of Cationic (IPr) Cu-I Complexes
- 2017
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Ingår i: Chemistry - A European Journal. - : Wiley-VCH Verlagsgesellschaft. - 0947-6539 .- 1521-3765. ; 23:64, s. 16328-16337
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Tidskriftsartikel (refereegranskat)abstract
- We report on the benefits of changing the bridging group X of bis-pyridyl ligands, that is, Py-X-Py where X is NH, CH2, C(CH3)(2), or PPh, on the photo-and electroluminescent properties of a new family of luminescent cationic H-heterocyclic carbene (NHC) copper(I) complexes. A joint experimental and theoretical study demonstrates that the bridging group affects the molecular conformation from a planar-like structure (X is NH and CH2) to a boat-like structure (X is C(CH3)(2) and PPh), leading to i) four-fold enhancement of the photoluminescence quantum yield (phi(em)) without affecting the thermally activated delayed fluorescence mechanism, and ii) one order of magnitude reduction of the ionic conductivity (sigma) of thin films. This leads to an overall enhancement of the device efficacy and luminance owing to the increased phi(em) and the use of low applied driving currents.
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| 3. |
- Giobbio, Ginevra, et al.
(författare)
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Design Rule Hidden from The Eye in S/N-Bridged Ancillary Ligands for Copper(I) Complexes Applied to Light-Emitting Electrochemical Cells
- 2023
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Ingår i: Advanced Functional Materials. - : WILEY-V C H VERLAG GMBH. - 1616-301X .- 1616-3028. ; 33:50
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Tidskriftsartikel (refereegranskat)abstract
- Enhancing low-energy emitting Cu(I)-ionic transition metal complexes (iTMCs) light-emitting electrochemical cells (LECs) is of utmost importance towards Cu(I)-iTMC-based white-emitting LECs. Here, the ancillary ligand design includes (i) extension of & pi;-systems and (ii) insertion of S-bridge between heteroaromatics rings. This led to two novel heteroleptic Cu(I)-iTMCs: 2-(pyridin-2-yl-l2-azanyl)quinoline (CuN2) and 2-(naphthalen-2-ylthio)quinoline (CuS2) as N<^>N and bis[(2-diphenylphosphino)phenyl] ether as P<^>P, exhibiting improved photoluminescence quantum yields (& phi;) and thermally activated delayed fluorescence processes compared to their reference Cu(I)-iTMCs: di(pyridin-2-yl)-l2-azane (CuN1) and di(pyridin-2-yl)sulfane (CuS1). Despite CuS2 stands out with the highest & phi; (38% vs 17 / 14 / 1% for CuN1 / CuN2 / CuS1), only CuN2-LECs show the expected enhanced performance (0.35 cd A(-1) at luminance of 117 cd m(-2)) compared to CuN1-LECs (0.02 cd A(-1) at6 cd m(-2)), while CuS2-LECs feature low performances (0.04 cd A(-1) at 10 cd m(-2)). This suggests that conventional chemical design rules are not effective towards enhancing device performance. Herein, nonconventional multivariate statistical analysis and electrochemical impedance spectroscopy studies allow to rationalize the mismatch between chemical design and device performance bringing to light a hidden design rule: polarizability of the ancillary ligand is key for an efficient Cu(I)-iTMC-LECs. All-in-all, this study provides fresh insights for the design of Cu-iTMCs fueling research on sustainable ion-based lighting sources.
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| 4. |
- Mahoro, Gilbert Umuhire, et al.
(författare)
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Towards rainbow photo/electro-luminescence in copper(i) complexes with the versatile bridged bis-pyridyl ancillary ligand
- 2021
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Ingår i: Dalton Transactions. - : ROYAL SOC CHEMISTRY. - 1477-9226 .- 1477-9234. ; 50:32, s. 11049-11060
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis and characterization of a family of copper(i) complexes bearing a bridged bis-pyridyl ancillary ligand is reported, highlighting how the bridge nature impacts the photo- and electro-luminescent behaviours within the family. In particular, the phosphonium bridge led to copper(i) complexes featuring good electrochemical stability and high ionic conductivity, as well as a stark blue-to-orange luminescence shift compared to the others. This resulted in high performance light-emitting electrochemical cells reaching stabilities of 10 mJ at ca. 40 cd m(-2) that are one order of magnitude higher than those of the other complexes. Overall, this work sheds light onto the crucial role of the bridge nature of the bis-pyridyl ancillary ligand on the photophysical features, film forming and, in turn, on the final device performances.
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| 5. |
- Marion, Ronan, et al.
(författare)
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NHC Copper(I) Complexes Bearing Dipyridylamine Ligands: Synthesis, Structural, and Photoluminescent Studies
- 2014
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Ingår i: Inorganic Chemistry. - : American Chemical Society. - 0020-1669 .- 1520-510X. ; 53:17, s. 9181-9191
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Tidskriftsartikel (refereegranskat)abstract
- We describe the synthesis of new cationic tricoordinated copper complexes bearing bidentate pyridine-type ligands and N-heterocyclic carbene as ancillary ligands. These cationic copper complexes were fully characterized by NMR, electrochemistry, X-ray analysis, and photophysical studies in different environments. Density functional theory calculations were also undertaken to rationalize the assignment of the electronic structure and the photophysical properties. These tricoordinated cationic copper complexes possess a stabilizing CH-pi interaction leading to high stability in both solid and liquid states. In addition, these copper complexes, bearing dipyridylamine ligands having a central nitrogen atom as potential anchoring point, exhibit very interesting luminescent properties that render them potential candidates for organic light-emitting diode applications.
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