The role of dinuclearity in promoting thermally activated delayed fluorescence (TADF) in cyclometallated, N^C^N-coordinated platinum(ii) complexes

Piotr Pander; Andrey V. Zaytsev; Amit Sil; J. A. Gareth Williams; Pierre-Henri Lanoe; Valery N. Kozhevnikov; Fernando B. Dias

doi:10.1039/d1tc02562g

The role of dinuclearity in promoting thermally activated delayed fluorescence (TADF) in cyclometallated, N^C^N-coordinated platinum(ii) complexes

Piotr Pander^*, Andrey V. Zaytsev, Amit Sil, J. A. Gareth Williams^*, Pierre-Henri Lanoe, Valery N. Kozhevnikov^*, Fernando B. Dias

^*Corresponding author for this work

Applied Sciences Department

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

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Abstract

We present the synthesis and in-depth photophysical analysis of a di-Pt(II) complex with a ditopic bis-N^C^N ligand. The complex exhibits a dual luminescent behaviour by emitting simultaneously delayed fluorescence and phosphorescence. By comparing with the mono-Pt(II) analogue, we demonstrate that thermally activated delayed fluorescence (TADF) is turned on in the di-Pt(II) complex due to the occurrence of three main differences relative to the mono-Pt(II) analogue: a larger singlet radiative rate constant (kSr), a smaller singlet–triplet energy gap (ΔEST) and a longer phosphorescence decay lifetime (τPH). We observe similar trends among other di-Pt(II) complexes and conclude that bimetallic structures promote conditions favourable for TADF to occur. The diplatinum(II) complex also shows a long wavelength-emissive excimer which yields near infrared electroluminescence, λel = 805 nm, in a solution-processed OLED device with EQEmax = 0.51%. We believe this is the highest efficiency reported to date for an excimer Pt(II) emitter with λel > 800 nm in a solution-processed OLED device.

Original language	English
Pages (from-to)	10276-10287
Number of pages	12
Journal	Journal of Materials Chemistry C
Volume	9
Issue number	32
Early online date	16 Jul 2021
DOIs	https://doi.org/10.1039/d1tc02562g
Publication status	Published - 19 Aug 2021

Keywords

Materials Chemistry
General Chemistry

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title = "The role of dinuclearity in promoting thermally activated delayed fluorescence (TADF) in cyclometallated, N^C^N-coordinated platinum(ii) complexes",

abstract = "We present the synthesis and in-depth photophysical analysis of a di-Pt(II) complex with a ditopic bis-N^C^N ligand. The complex exhibits a dual luminescent behaviour by emitting simultaneously delayed fluorescence and phosphorescence. By comparing with the mono-Pt(II) analogue, we demonstrate that thermally activated delayed fluorescence (TADF) is turned on in the di-Pt(II) complex due to the occurrence of three main differences relative to the mono-Pt(II) analogue: a larger singlet radiative rate constant (kSr), a smaller singlet–triplet energy gap (ΔEST) and a longer phosphorescence decay lifetime (τPH). We observe similar trends among other di-Pt(II) complexes and conclude that bimetallic structures promote conditions favourable for TADF to occur. The diplatinum(II) complex also shows a long wavelength-emissive excimer which yields near infrared electroluminescence, λel = 805 nm, in a solution-processed OLED device with EQEmax = 0.51%. We believe this is the highest efficiency reported to date for an excimer Pt(II) emitter with λel > 800 nm in a solution-processed OLED device.",

keywords = "Materials Chemistry, General Chemistry",

author = "Piotr Pander and Zaytsev, {Andrey V.} and Amit Sil and Williams, {J. A. Gareth} and Pierre-Henri Lanoe and Kozhevnikov, {Valery N.} and Dias, {Fernando B.}",

note = "Funding Information: We thank EPSRC (grant ref. EP/S012788/1 and EP/S01280X) for support of this work. We are grateful to Dr Dmitry Yufit at Durham Chemistry for determining the crystal structure of complex 2 and for his continued assistance with crystallography. This work made use of the facilities of the Hamilton HPC Service of Durham University.",

year = "2021",

month = aug,

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doi = "10.1039/d1tc02562g",

language = "English",

volume = "9",

pages = "10276--10287",

journal = "Journal of Materials Chemistry C",

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TY - JOUR

T1 - The role of dinuclearity in promoting thermally activated delayed fluorescence (TADF) in cyclometallated, N^C^N-coordinated platinum(ii) complexes

AU - Pander, Piotr

AU - Zaytsev, Andrey V.

AU - Sil, Amit

AU - Williams, J. A. Gareth

AU - Lanoe, Pierre-Henri

AU - Kozhevnikov, Valery N.

AU - Dias, Fernando B.

N1 - Funding Information: We thank EPSRC (grant ref. EP/S012788/1 and EP/S01280X) for support of this work. We are grateful to Dr Dmitry Yufit at Durham Chemistry for determining the crystal structure of complex 2 and for his continued assistance with crystallography. This work made use of the facilities of the Hamilton HPC Service of Durham University.

PY - 2021/8/19

Y1 - 2021/8/19

N2 - We present the synthesis and in-depth photophysical analysis of a di-Pt(II) complex with a ditopic bis-N^C^N ligand. The complex exhibits a dual luminescent behaviour by emitting simultaneously delayed fluorescence and phosphorescence. By comparing with the mono-Pt(II) analogue, we demonstrate that thermally activated delayed fluorescence (TADF) is turned on in the di-Pt(II) complex due to the occurrence of three main differences relative to the mono-Pt(II) analogue: a larger singlet radiative rate constant (kSr), a smaller singlet–triplet energy gap (ΔEST) and a longer phosphorescence decay lifetime (τPH). We observe similar trends among other di-Pt(II) complexes and conclude that bimetallic structures promote conditions favourable for TADF to occur. The diplatinum(II) complex also shows a long wavelength-emissive excimer which yields near infrared electroluminescence, λel = 805 nm, in a solution-processed OLED device with EQEmax = 0.51%. We believe this is the highest efficiency reported to date for an excimer Pt(II) emitter with λel > 800 nm in a solution-processed OLED device.

AB - We present the synthesis and in-depth photophysical analysis of a di-Pt(II) complex with a ditopic bis-N^C^N ligand. The complex exhibits a dual luminescent behaviour by emitting simultaneously delayed fluorescence and phosphorescence. By comparing with the mono-Pt(II) analogue, we demonstrate that thermally activated delayed fluorescence (TADF) is turned on in the di-Pt(II) complex due to the occurrence of three main differences relative to the mono-Pt(II) analogue: a larger singlet radiative rate constant (kSr), a smaller singlet–triplet energy gap (ΔEST) and a longer phosphorescence decay lifetime (τPH). We observe similar trends among other di-Pt(II) complexes and conclude that bimetallic structures promote conditions favourable for TADF to occur. The diplatinum(II) complex also shows a long wavelength-emissive excimer which yields near infrared electroluminescence, λel = 805 nm, in a solution-processed OLED device with EQEmax = 0.51%. We believe this is the highest efficiency reported to date for an excimer Pt(II) emitter with λel > 800 nm in a solution-processed OLED device.

KW - Materials Chemistry

KW - General Chemistry

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U2 - 10.1039/d1tc02562g

DO - 10.1039/d1tc02562g

M3 - Article

SN - 2050-7526

VL - 9

SP - 10276

EP - 10287

JO - Journal of Materials Chemistry C

JF - Journal of Materials Chemistry C

IS - 32

ER -

The role of dinuclearity in promoting thermally activated delayed fluorescence (TADF) in cyclometallated, N^C^N-coordinated platinum(ii) complexes

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