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Shafikov, M. Z., Tang, S., Larsen, C., Bodensteiner, M., Kozhevnikov, V. N. & Edman, L. (2019). An efficient heterodinuclear Ir(III)/Pt(II) complex: synthesis, photophysics and application in light-emitting electrochemical cells. Journal of Materials Chemistry C, 7(34), 10672-10682
Open this publication in new window or tab >>An efficient heterodinuclear Ir(III)/Pt(II) complex: synthesis, photophysics and application in light-emitting electrochemical cells
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2019 (English)In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 7, no 34, p. 10672-10682Article in journal (Refereed) Published
Abstract [en]

We report on the design, synthesis, characterization and successful application of a heterodinuclear Ir(III)/Pt(II) complex endowed with two 4,6-diphenylpyrimidine ligands and two acetylacetonate ligands, with one of the former being the rigid bridging unit between the two metal centers. The heterodinuclear complex exhibits red phosphorescence with a high quantum yield of Phi(PL) = 85% and a short room-temperature decay time of tau = 640 ns in degassed toluene solution. The high efficiency of the spin-forbidden T-1 -> S-0 transition is demonstrated to originate in a strong spin-orbit coupling of the T-1 state with a manifold of excited singlet states, which contributes to the record-breaking zero-field splitting of the T-1 state of 240 cm(-1). The high-solubility and non-ionic hetero-dinuclear complex was employed as the emissive guest compound in host-guest light-emitting electrochemical cells, and such optimized devices delivered vibrant red emission (lambda(peak) = 615 nm) with a second-fast turn-on and a high external quantum efficiency of 2.7% at a luminance of 265 cd m(-2).

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2019
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:umu:diva-164505 (URN)10.1039/c9tc02930c (DOI)000483684600026 ()
Available from: 2019-11-22 Created: 2019-11-22 Last updated: 2019-11-22Bibliographically approved
Xiong, W., Tang, S., Murto, P., Zhu, W., Edman, L. & Wang, E. (2019). Combining Benzotriazole and Benzodithiophene Host Units in Host-Guest Polymers for Efficient and Stable Near-Infrared Emission from Light-Emitting Electrochemical Cells. Advanced Optical Materials, 7(15), Article ID 1900280.
Open this publication in new window or tab >>Combining Benzotriazole and Benzodithiophene Host Units in Host-Guest Polymers for Efficient and Stable Near-Infrared Emission from Light-Emitting Electrochemical Cells
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2019 (English)In: Advanced Optical Materials, ISSN 2162-7568, E-ISSN 2195-1071, Vol. 7, no 15, article id 1900280Article in journal (Refereed) Published
Abstract [en]

A set of host-guest copolymers with alternating benzodithiophene and benzotriazole (BTz) derivatives as host units and 4,7-bis(5-bromothiophen-2-yl)-benzo[c][1,2,5]thiadiazole as the minority guest are synthesized, characterized, and evaluated for applications. A light-emitting electrochemical cell (LEC) comprising such a host-guest copolymer delivers fast-response near-infrared (NIR) emission peaked at 723 nm with a high radiance of 169 mu W cm(-2) at a low drive voltage of 3.6 V. The NIR-LEC also features good stability, as the peak NIR output only drops by 8% after 350 h of continuous operation. It is, however, found that the LEC performance is highly sensitive to the detailed chemical structure of the host backbone, and that the addition of electron-donating thiophene bridging units onto the BTz unit is highly positive while the inclusion of fluorine atoms results in a drastically lowered performance, presumably because of the emergence of hydrogen bonding within the active material.

Keywords
conjugated polymers, host-guest copolymers, near-infrared emission light-emitting electrochemical cells
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:umu:diva-162672 (URN)10.1002/adom.201900280 (DOI)000478735800007 ()
Available from: 2019-08-29 Created: 2019-08-29 Last updated: 2019-08-29Bibliographically approved
Gerz, I., Lindh, E. M., Thordarson, P., Edman, L., Kullgren, J. & Mindemark, J. (2019). Oligomer Electrolytes for Light-Emitting Electrochemical Cells: Influence of the End Groups on Ion Coordination, Ion Binding, and Turn-on Kinetics. ACS Applied Materials and Interfaces, 11(43), 40372-40381
Open this publication in new window or tab >>Oligomer Electrolytes for Light-Emitting Electrochemical Cells: Influence of the End Groups on Ion Coordination, Ion Binding, and Turn-on Kinetics
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2019 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 43, p. 40372-40381Article in journal (Refereed) Published
Abstract [en]

The electrolyte is an essential constituent of the light-emitting electrochemical cell (LEC), since its operating mechanism is dependent on the redistribution of mobile ions in the active layer. Recent developments of new ion transporters have yielded high-performance devices, but knowledge about the interactions between the ionic species and the ion transporters and the influence of these interactions on the LEC performance is lacking. We therefore present a combined computational and experimental effort that demonstrates that the selection of the end group in a star-branched oligomeric ion transporter based on trimethylolpropane ethoxylate has a paramount influence on the ionic interactions in the electrolyte and thereby also on the performance of the corresponding LECs. With hydroxyl end groups, the the salt is strongly coordinated to the ion transporter, which leads to suppression of ion pairing, but the penalty is a hindered ion release and a slow turn-on for the LEC devices. With methoxy end groups, an intermediate coordination strength is seen together with the formation of contact ion pairs, but the LEC performance is very good with fast turn-on. Using a series of ion transporters with alkyl carbonate end groups, the ion transporter:cation coordination strength is lowered further, but the turn-on kinetics are slower than what is seen for devices comprising the methoxy end-capped ion transporter.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
light-emitting electrochemical cells, polymer electrolytes, coordination, binding energy, ion pairing
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:umu:diva-165349 (URN)10.1021/acsami.9b15233 (DOI)000493869700099 ()31621280 (PubMedID)
Funder
Lars Hierta Memorial FoundationeSSENCE - An eScience CollaborationSwedish Foundation for Strategic Research Swedish Research CouncilSwedish Energy Agency
Available from: 2019-11-26 Created: 2019-11-26 Last updated: 2019-11-26Bibliographically approved
Tang, S., Murto, P., Wang, J., Larsen, C., Andersson, M. R., Wang, E. & Edman, L. (2019). On the Design of Host-Guest Light-Emitting Electrochemical Cells: Should the Guest be Physically Blended or Chemically Incorporated into the Host for Efficient Emission?. Advanced Optical Materials, 7(18), Article ID 1900451.
Open this publication in new window or tab >>On the Design of Host-Guest Light-Emitting Electrochemical Cells: Should the Guest be Physically Blended or Chemically Incorporated into the Host for Efficient Emission?
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2019 (English)In: Advanced Optical Materials, ISSN 2162-7568, E-ISSN 2195-1071, Vol. 7, no 18, article id 1900451Article in journal (Refereed) Published
Abstract [en]

It has recently been demonstrated that light‐emitting electrochemical cells (LECs) can be designed to deliver strong emission with high efficiency when the charge transport is effectuated by a majority host and the emission is executed by a minority guest. A relevant question is then: should the guest be physically blended with or chemically incorporated into the host? A systematic study is presented that establishes that for near‐infrared‐(NIR‐) emitting LECs based on poly(indacenodithieno[3,2‐b]thiophene) (PIDTT) as the host and 4,7‐bis(4,4‐bis(2‐ethylhexyl)‐4H‐silolo[3,2‐b:4,5‐b′]dithiophen‐2‐yl)benzo[c][1,2,5]‐thiadiazole (SBS) as the guest the chemical‐incorporation approach is preferable. The host‐to‐guest energy transfer in LEC devices is highly efficient at a low guest concentration of 0.5%, whereas guest aggregation and ion redistribution during device operation severly inhibits this transfer in the physical‐blend devices. The chemical‐incorporation approach also results in a redshifted emission with a somewhat lowered photoluminescence quantum yield, but the LEC performance is nevertheless very good. Specifically, an NIR‐LEC device comprising a guest‐dilute (0.5 molar%) PIDTT‐SBS copolymer delivers highly stabile operation at a high radiance of 263 µW cm−2 (peak wavelength = 725 nm) and with an external quantum efficiency of 0.214%, which is close to the theoretical limit for this particular emitter and device geometry.

Place, publisher, year, edition, pages
John Wiley & Sons, 2019
Keywords
host-guest copolymers, intramolecular energy transfer, light-emitting electrochemical cells, near-infrared emission
National Category
Materials Engineering Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:umu:diva-164065 (URN)10.1002/adom.201900451 (DOI)000487087400020 ()
Available from: 2019-10-15 Created: 2019-10-15 Last updated: 2019-10-15Bibliographically approved
Tang, S., Murto, P., Wang, J., Larsen, C., Andersson, M. R., Wang, E. & Edman, L. (2019). On the Design of Host-Guest Light-Emitting Electrochemical Cells: Should the Guest be Physically Blended or Chemically Incorporated into the Host for Efficient Emission?. Advanced Optical Materials, 7(18), Article ID 1900451.
Open this publication in new window or tab >>On the Design of Host-Guest Light-Emitting Electrochemical Cells: Should the Guest be Physically Blended or Chemically Incorporated into the Host for Efficient Emission?
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2019 (English)In: Advanced Optical Materials, ISSN 2162-7568, E-ISSN 2195-1071, Vol. 7, no 18, article id 1900451Article in journal (Refereed) Published
Abstract [en]

It has recently been demonstrated that light-emitting electrochemical cells (LECs) can be designed to deliver strong emission with high efficiency when the charge transport is effectuated by a majority host and the emission is executed by a minority guest. A relevant question is then: should the guest be physically blended with or chemically incorporated into the host? A systematic study is presented that establishes that for near-infrared-(NIR-) emitting LECs based on poly(indacenodithieno[3,2-b]thiophene) (PIDTT) as the host and 4,7-bis(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b ']dithiophen-2-yl)benzo[c][1,2,5]-thiadiazole (SBS) as the guest the chemical-incorporation approach is preferable. The host-to-guest energy transfer in LEC devices is highly efficient at a low guest concentration of 0.5%, whereas guest aggregation and ion redistribution during device operation severly inhibits this transfer in the physical-blend devices. The chemical-incorporation approach also results in a redshifted emission with a somewhat lowered photoluminescence quantum yield, but the LEC performance is nevertheless very good. Specifically, an NIR-LEC device comprising a guest-dilute (0.5 molar%) PIDTT-SBS copolymer delivers highly stabile operation at a high radiance of 263 mu W cm(-2) (peak wavelength = 725 nm) and with an external quantum efficiency of 0.214%, which is close to the theoretical limit for this particular emitter and device geometry.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2019
Keywords
host-guest copolymers, intramolecular energy transfer, light-emitting electrochemical cells, near- infrared emission
National Category
Atom and Molecular Physics and Optics Polymer Chemistry
Identifiers
urn:nbn:se:umu:diva-164143 (URN)10.1002/adom.201900451 (DOI)000487087400020 ()
Available from: 2019-10-17 Created: 2019-10-17 Last updated: 2019-10-17Bibliographically approved
Lindh, E. M., Lundberg, P., Lanz, T. & Edman, L. (2019). Optical analysis of light-emitting electrochemical cells. Scientific Reports, 9, Article ID 10433.
Open this publication in new window or tab >>Optical analysis of light-emitting electrochemical cells
2019 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 10433Article in journal (Refereed) Published
Abstract [en]

The light-emitting electrochemical cell (LEC) is a contender for emerging applications of light, primarily because it offers low-cost solution fabrication of easily functionalized device architectures. The attractive properties originate in the in-situ formation of electrochemically doped transport regions that enclose an emissive intrinsic region, but the understanding of how this intricate doping structure affects the optical performance of the LEC is largely lacking. We combine angle- and doping-dependent measurements and simulations, and demonstrate that the emission zone in our high-performance LEC is centered at ~30% of the active-layer thickness (dal) from the anode. We further find that the emission intensity and efficiency are undulating with dal, and establish that the first emission maximum at dal ~ 100 nm is largely limited by the lossy coupling of excitons to the doping regions, whereas the most prominent loss channel at the second maximum at dal ~ 300 nm is wave-guided modes.

Place, publisher, year, edition, pages
Nature Publishing Group, 2019
National Category
Nano Technology Condensed Matter Physics
Identifiers
urn:nbn:se:umu:diva-156092 (URN)10.1038/s41598-019-46860-y (DOI)000475845400037 ()31320711 (PubMedID)2-s2.0-85069470003 (Scopus ID)
Note

Originally included in thesis in manuscript form.

Available from: 2019-02-05 Created: 2019-02-05 Last updated: 2019-08-08Bibliographically approved
Mone, M., Tang, S., Murto, P., Abdulahi, B. A., Larsen, C., Wang, J., . . . Wang, E. (2019). Star-Shaped Diketopyrrolopyrrole-Zinc Porphyrin that Delivers 900 nm Emission in Light-Emitting Electrochemical Cells. Chemistry of Materials, 31(23), 9721-9728
Open this publication in new window or tab >>Star-Shaped Diketopyrrolopyrrole-Zinc Porphyrin that Delivers 900 nm Emission in Light-Emitting Electrochemical Cells
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2019 (English)In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 31, no 23, p. 9721-9728Article in journal (Refereed) Published
Abstract [en]

The development and application of a deep near-infrared (NIR) emitting star-shaped diketopyrrolopyrrole–Zn-porphyrin compound, ZnP(TDPP)4, is reported. The structure, conjugation, and planarity of the porphyrin compound were carefully tuned by molecular design, which resulted in a low-energy photoluminescence peak at 872 nm. The ZnP(TDPP)4 compound was employed as the emissive guest in light-emitting electrochemical cells (LECs), which also comprised the conjugated polymer poly[1,3-bis(2-ethylhexyl)-5-(5-(6-methyl-4,8-bis(5-(tributylsilyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophen-2-yl)thiophen-2-yl)-7-(5-methylthiophen-2-yl)-4H,8H-benzo[1,2-c:4,5-c′]dithiophene-4,8-dione] (PBDTSi-BDD) as the majority host, an ionic liquid as the electrolyte, and two air-stabile electrodes. These systematically optimized host–guest LECs featured a peak electroluminescence at 900 nm, which was delivered at a significant radiance of 36 μW/cm2 and at a low drive voltage of 3.8 V. It is notable that this is the most redshifted NIR emission attained from an LEC device to date, and as such, this work introduces Zn porphyrins as a sustainable and tunable option for emerging emissive NIR applications.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:umu:diva-167055 (URN)10.1021/acs.chemmater.9b03312 (DOI)000502418000015 ()
Funder
Swedish Foundation for Strategic Research The Kempe FoundationsSwedish Research CouncilSwedish Research Council FormasWallenberg Foundations, 2017.0186Wallenberg Foundations, 2016.0059
Available from: 2020-01-09 Created: 2020-01-09 Last updated: 2020-01-09Bibliographically approved
Lundberg, P., Tsuchiya, Y., Lindh, E. M., Tang, S., Adachi, C. & Edman, L. (2019). Thermally activated delayed fluorescence with 7% external quantum efficiency from a light-emitting electrochemical cell. Nature Communications, 10, Article ID 5307.
Open this publication in new window or tab >>Thermally activated delayed fluorescence with 7% external quantum efficiency from a light-emitting electrochemical cell
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2019 (English)In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 10, article id 5307Article in journal (Refereed) Published
Abstract [en]

We report on light-emitting electrochemical cells, comprising a solution-processed single-layer active material and air-stabile electrodes, that exhibit efficient and bright thermally activated delayed fluorescence. Our optimized devices delivers a luminance of 120 cdm-2 at an external quantum efficiency of 7.0%. As such, it outperforms the combined luminance/efficiency state-of-the art for thermally activated delayed fluorescence light-emitting electrochemical cells by one order of magnitude. For this end, we employed a polymeric blend host for balanced electrochemical doping and electronic transport as well as uniform film formation, an optimized concentration (<1 mass%) of guest for complete host-to-guest energy transfer at minimized aggregation and efficient emission, and an appropriate concentration of an electrochemically stabile electrolyte for desired doping effects. The generic nature of our approach is manifested in the attainment of bright and efficient thermally activated delayed fluorescence emission from three different light-emitting electrochemical cells with invariant host:guest:electrolyte number ratio.

Place, publisher, year, edition, pages
Nature Publishing Group, 2019
National Category
Other Physics Topics
Identifiers
urn:nbn:se:umu:diva-166389 (URN)10.1038/s41467-019-13289-w (DOI)000498195100005 ()31757959 (PubMedID)
Available from: 2019-12-17 Created: 2019-12-17 Last updated: 2019-12-17Bibliographically approved
Dahlberg, T., Stangner, T., Hanqing, Z., Wiklund, K., Lundberg, P., Edman, L. & Andersson, M. (2018). 3D printed water-soluble scaffolds for rapid production of PDMS micro-fluidic flow chambers. Scientific Reports, 8(1), Article ID 3372.
Open this publication in new window or tab >>3D printed water-soluble scaffolds for rapid production of PDMS micro-fluidic flow chambers
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2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, no 1, article id 3372Article in journal (Refereed) Published
Abstract [en]

We report a novel method for fabrication of three-dimensional (3D) biocompatible micro-fluidic flow chambers in polydimethylsiloxane (PDMS) by 3D-printing water-soluble polyvinyl alcohol (PVA) filaments as master scaffolds. The scaffolds are first embedded in the PDMS and later residue-free dissolved in water leaving an inscription of the scaffolds in the hardened PDMS. We demonstrate the strength of our method using a regular, cheap 3D printer, and evaluate the inscription process and the channels micro-fluidic properties using image analysis and digital holographic microscopy. Furthermore, we provide a protocol that allows for direct printing on coverslips and we show that flow chambers with a channel cross section down to 40 x 300 μm can be realized within 60 min. These flow channels are perfectly transparent, biocompatible and can be used for microscopic applications without further treatment. Our proposed protocols facilitate an easy, fast and adaptable production of micro-fluidic channel designs that are cost-effective, do not require specialized training and can be used for a variety of cell and bacterial assays. To help readers reproduce our micro-fluidic devices, we provide: full preparation protocols, 3D-printing CAD files for channel scaffolds and our custom-made molding device, 3D printer build-plate leveling instructions, and G-code.

Place, publisher, year, edition, pages
Nature Publishing Group, 2018
National Category
Other Materials Engineering Other Engineering and Technologies not elsewhere specified Other Physics Topics
Identifiers
urn:nbn:se:umu:diva-144631 (URN)10.1038/s41598-018-21638-w (DOI)000425500300044 ()
Funder
Swedish Research Council, 2013-5379The Kempe Foundations, JCK-1622
Available from: 2018-02-08 Created: 2018-02-08 Last updated: 2018-08-16Bibliographically approved
Ekeroth, S., Münger, E. P., Boyd, R., Ekspong, J., Wågberg, T., Edman, L., . . . Helmersson, U. (2018). Catalytic nanotruss structures realized by magnetic self-assembly in pulsed plasma. Nano letters (Print), 18(5), 3132-3137
Open this publication in new window or tab >>Catalytic nanotruss structures realized by magnetic self-assembly in pulsed plasma
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2018 (English)In: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 18, no 5, p. 3132-3137Article in journal (Refereed) Published
Abstract [en]

Tunable nanostructures that feature a high surface area are firmly attached to a conducting substrate and can be fabricated efficiently over significant areas, which are of interest for a wide variety of applications in, for instance, energy storage and catalysis. We present a novel approach to fabricate Fe nanoparticles using a pulsed-plasma process and their subsequent guidance and self-organization into well-defined nanostructures on a substrate of choice by the use of an external magnetic field. A systematic analysis and study of the growth procedure demonstrate that nondesired nanoparticle agglomeration in the plasma phase is hindered by electrostatic repulsion, that a polydisperse nanoparticle distribution is a consequence of the magnetic collection, and that the formation of highly networked nanotruss structures is a direct result of the polydisperse nanoparticle distribution. The nanoparticles in the nanotruss are strongly connected, and their outer surfaces are covered with a 2 nm layer of iron oxide. A 10 μm thick nanotruss structure was grown on a lightweight, flexible and conducting carbon-paper substrate, which enabled the efficient production of H2 gas from water splitting at a low overpotential of 210 mV and at a current density of 10 mA/cm2.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
Keywords
nanotrusses, nanowires, nanoparticles, iron, electrocatalysis, pulsed sputtering
National Category
Nano Technology
Identifiers
urn:nbn:se:umu:diva-148834 (URN)10.1021/acs.nanolett.8b00718 (DOI)000432093200055 ()29624405 (PubMedID)
Available from: 2018-06-12 Created: 2018-06-12 Last updated: 2018-06-12Bibliographically approved
Projects
Light-emitting electrochemical cells for low-cost and ´green´ lighting and displays [2011-00584_Vinnova]; Umeå UniversityOrganisk elektronik - nanodesign för funktionella applikationer [P34145-2_Energi]; Umeå University; Publications
Enevold, J., Larsen, C., Zakrisson, J., Andersson, M. & Edman, L. (2018). Realizing large-area arrays of semiconducting fullerene nanostructures with direct laser interference patterning. Nano letters (Print), 18(1), 540-545
The light-emitting electrochemical cell: Developing rational design principles for efficient, bright and green operation [2017-04380_VR]; Umeå University; Publications
Enevold, J., Dahlberg, T., Stangner, T., Tang, S., Lindh, E. M., Gracia-Espino, E., . . . Edman, L.Tunable two-dimensional patterning of a semiconducting C60 fullerene film using a spatial light modulator.
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2495-7037

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