Fast and Tunable Phosphorescence from Organic Ionic Crystals

Iida Partanen; Omar Al-Saedy; Toni Eskelinen; Antti J. Karttunen; Jarkko J. Saarinen; Ondrej Mrózek; Andreas Steffen; Andrey Belyaev; Pi-Tai Chou; Igor O. Koshevoy

doi:10.1002/anie.202305108

Fast and Tunable Phosphorescence from Organic Ionic Crystals

Iida Partanen
, Omar Al-Saedy
, Toni Eskelinen
, Antti J. Karttunen
, Jarkko J. Saarinen
, Ondrej Mrózek
, Andreas Steffen^*
, Andrey Belyaev^*
, Pi-Tai Chou^*
, Igor O. Koshevoy^*

^*Corresponding author for this work

University of Eastern Finland
TU Dortmund University
University of Jyväskylä
National Taiwan University

Research output: Contribution to journal › Article › Scientific › peer-review

34 Citations (Scopus)

65 Downloads (Pure)

Abstract

Crystalline diphosphonium iodides [MeR₂P-spacer-R₂Me]I with phenylene (1, 2), naphthalene (3, 4), biphenyl (5) and anthracene (6) as aromatic spacers, are photoemissive under ambient conditions. The emission colors (λ_em values from 550 to 880 nm) and intensities (Φ_em reaching 0.75) are defined by the composition and substitution geometry of the central conjugated chromophore motif, and the anion-π interactions. Time-resolved and variable-temperature luminescence studies suggest phosphorescence for all the titled compounds, which demonstrate observed lifetimes of 0.46–92.23 μs at 297 K. Radiative rate constants k_r as high as 2.8×10⁵ s⁻¹ deduced for salts 1–3 were assigned to strong spin-orbit coupling enhanced by an external heavy atom effect arising from the anion-π charge-transfer character of the triplet excited state. These rates of anomalously fast metal-free phosphorescence are comparable to those of transition metal complexes and organic luminophores that utilize triplet excitons via a thermally activated delayed fluorescence mechanism, making such ionic luminophores a new paradigm for the design of photofunctional and responsive molecular materials.

Original language	English
Article number	e202305108
Number of pages	9
Journal	Angewandte Chemie - International Edition
Volume	62
Issue number	36
Early online date	16 Jun 2023
DOIs	https://doi.org/10.1002/anie.202305108
Publication status	Published - 4 Sept 2023
MoE publication type	A1 Journal article-refereed

Funding

Financial support from the Academy of Finland (decision 351618, I.O.K.; decision 340584, T.E. and A.J.K.; decision 339544, J.J.S.; Flagship Programme, Photonics Research and Innovation PREIN, decision 320166), Alexander von Humboldt and Otto A. Malm Foundations (A.B.), and the National Science and Technology Council (NSTC), Taiwan, are gratefully acknowledged.

Keywords

Anion-π Interactions
Charge Transfer
Crystal Engineering
Phosphonium Salt
Phosphorescence

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10.1002/anie.202305108Licence: CC BY

CHEM_Partanen_et_al_Fast_and_Tunable_2023_Angewandte_ChemieFinal published version, 3.46 MBLicence: CC BY

Cite this

@article{62ec0c1f3637493e8baa334db9f9893c,

title = "Fast and Tunable Phosphorescence from Organic Ionic Crystals",

abstract = "Crystalline diphosphonium iodides [MeR2P-spacer-R2Me]I with phenylene (1, 2), naphthalene (3, 4), biphenyl (5) and anthracene (6) as aromatic spacers, are photoemissive under ambient conditions. The emission colors (λem values from 550 to 880 nm) and intensities (Φem reaching 0.75) are defined by the composition and substitution geometry of the central conjugated chromophore motif, and the anion-π interactions. Time-resolved and variable-temperature luminescence studies suggest phosphorescence for all the titled compounds, which demonstrate observed lifetimes of 0.46–92.23 μs at 297 K. Radiative rate constants kr as high as 2.8×105 s−1 deduced for salts 1–3 were assigned to strong spin-orbit coupling enhanced by an external heavy atom effect arising from the anion-π charge-transfer character of the triplet excited state. These rates of anomalously fast metal-free phosphorescence are comparable to those of transition metal complexes and organic luminophores that utilize triplet excitons via a thermally activated delayed fluorescence mechanism, making such ionic luminophores a new paradigm for the design of photofunctional and responsive molecular materials.",

keywords = "Anion-π Interactions, Charge Transfer, Crystal Engineering, Phosphonium Salt, Phosphorescence",

author = "Iida Partanen and Omar Al-Saedy and Toni Eskelinen and Karttunen, \{Antti J.\} and Saarinen, \{Jarkko J.\} and Ondrej Mr{\'o}zek and Andreas Steffen and Andrey Belyaev and Pi-Tai Chou and Koshevoy, \{Igor O.\}",

note = "Funding Information: Financial support from the Academy of Finland (decision 351618, I.O.K.; decision 340584, T.E. and A.J.K.; decision 339544, J.J.S.; Flagship Programme, Photonics Research and Innovation PREIN, decision 320166), Alexander von Humboldt and Otto A. Malm Foundations (A.B.), and the National Science and Technology Council (NSTC), Taiwan, are gratefully acknowledged. Publisher Copyright: {\textcopyright} 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.",

year = "2023",

month = sep,

day = "4",

doi = "10.1002/anie.202305108",

language = "English",

volume = "62",

journal = "Angewandte Chemie - International Edition",

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TY - JOUR

T1 - Fast and Tunable Phosphorescence from Organic Ionic Crystals

AU - Partanen, Iida

AU - Al-Saedy, Omar

AU - Eskelinen, Toni

AU - Karttunen, Antti J.

AU - Saarinen, Jarkko J.

AU - Mrózek, Ondrej

AU - Steffen, Andreas

AU - Belyaev, Andrey

AU - Chou, Pi-Tai

AU - Koshevoy, Igor O.

N1 - Funding Information: Financial support from the Academy of Finland (decision 351618, I.O.K.; decision 340584, T.E. and A.J.K.; decision 339544, J.J.S.; Flagship Programme, Photonics Research and Innovation PREIN, decision 320166), Alexander von Humboldt and Otto A. Malm Foundations (A.B.), and the National Science and Technology Council (NSTC), Taiwan, are gratefully acknowledged. Publisher Copyright: © 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.

PY - 2023/9/4

Y1 - 2023/9/4

N2 - Crystalline diphosphonium iodides [MeR2P-spacer-R2Me]I with phenylene (1, 2), naphthalene (3, 4), biphenyl (5) and anthracene (6) as aromatic spacers, are photoemissive under ambient conditions. The emission colors (λem values from 550 to 880 nm) and intensities (Φem reaching 0.75) are defined by the composition and substitution geometry of the central conjugated chromophore motif, and the anion-π interactions. Time-resolved and variable-temperature luminescence studies suggest phosphorescence for all the titled compounds, which demonstrate observed lifetimes of 0.46–92.23 μs at 297 K. Radiative rate constants kr as high as 2.8×105 s−1 deduced for salts 1–3 were assigned to strong spin-orbit coupling enhanced by an external heavy atom effect arising from the anion-π charge-transfer character of the triplet excited state. These rates of anomalously fast metal-free phosphorescence are comparable to those of transition metal complexes and organic luminophores that utilize triplet excitons via a thermally activated delayed fluorescence mechanism, making such ionic luminophores a new paradigm for the design of photofunctional and responsive molecular materials.

AB - Crystalline diphosphonium iodides [MeR2P-spacer-R2Me]I with phenylene (1, 2), naphthalene (3, 4), biphenyl (5) and anthracene (6) as aromatic spacers, are photoemissive under ambient conditions. The emission colors (λem values from 550 to 880 nm) and intensities (Φem reaching 0.75) are defined by the composition and substitution geometry of the central conjugated chromophore motif, and the anion-π interactions. Time-resolved and variable-temperature luminescence studies suggest phosphorescence for all the titled compounds, which demonstrate observed lifetimes of 0.46–92.23 μs at 297 K. Radiative rate constants kr as high as 2.8×105 s−1 deduced for salts 1–3 were assigned to strong spin-orbit coupling enhanced by an external heavy atom effect arising from the anion-π charge-transfer character of the triplet excited state. These rates of anomalously fast metal-free phosphorescence are comparable to those of transition metal complexes and organic luminophores that utilize triplet excitons via a thermally activated delayed fluorescence mechanism, making such ionic luminophores a new paradigm for the design of photofunctional and responsive molecular materials.

KW - Anion-π Interactions

KW - Charge Transfer

KW - Crystal Engineering

KW - Phosphonium Salt

KW - Phosphorescence

UR - https://www.scopus.com/pages/publications/85162055107

U2 - 10.1002/anie.202305108

DO - 10.1002/anie.202305108

M3 - Article

AN - SCOPUS:85162055107

SN - 1433-7851

VL - 62

JO - Angewandte Chemie - International Edition

JF - Angewandte Chemie - International Edition

IS - 36

M1 - e202305108

ER -

Fast and Tunable Phosphorescence from Organic Ionic Crystals

Abstract

Funding

Keywords

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CCDC 2206827: Experimental Crystal Structure Determination

CCDC 2206825: Experimental Crystal Structure Determination

CCDC 2264399: Experimental Crystal Structure Determination

LUMICOIN: Optical and photophysical properties of luminescent coinage-metal compounds

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Fast and Tunable Phosphorescence from Organic Ionic Crystals

Abstract

Funding

Keywords

Access to Document

Other files and links

Fingerprint

Datasets

CCDC 2206827: Experimental Crystal Structure Determination

CCDC 2206825: Experimental Crystal Structure Determination

CCDC 2264399: Experimental Crystal Structure Determination

Projects

LUMICOIN: Optical and photophysical properties of luminescent coinage-metal compounds

Cite this