Balanced Energy Gaps as a Key Design Rule for Solution-Phase Organic Room Temperature Phosphorescence

Simon Paredis; Tom Cardeynaels; Suman Kuila; Jasper Deckers; Melissa Van Landeghem; Koen Vandewal; Andrew Danos; Andrew P. Monkman; Benoît Champagne; Wouter Maes

doi:10.1002/chem.202301369

Balanced Energy Gaps as a Key Design Rule for Solution-Phase Organic Room Temperature Phosphorescence

Simon Paredis, Tom Cardeynaels, Suman Kuila, Jasper Deckers, Melissa Van Landeghem, Koen Vandewal, Andrew Danos, Andrew P. Monkman, Benoît Champagne, Wouter Maes

University of Namur

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

Abstract

Metal-free organic emitters that display solution-phase room temperature phosphorescence (sRTP) remain exceedingly rare. Here, we investigate the structural and photophysical properties that support sRTP by comparing a recently reported sRTP compound (BTaz−Th−PXZ) to two novel analogous materials, replacing the donor group by either acridine or phenothiazine. The emissive triplet excited state remains fixed in all three cases, while the emissive charge-transfer singlet states (and the calculated paired charge-transfer T₂ state) vary with the donor unit. While all three materials show dominant RTP in film, in solution different singlet-triplet and triplet-triplet energy gaps give rise to triplet-triplet annihilation followed by weak sRTP for the new compounds, compared to dominant sRTP throughout for the original PXZ material. Engineering both the sRTP state and higher charge-transfer states therefore emerges as a crucial element in designing emitters capable of sRTP.

Original language	English
Article number	e202301369
Journal	Chemistry: A European Journal
Volume	29
Issue number	42
DOIs	https://doi.org/10.1002/chem.202301369
Publication status	Published - 26 Jul 2023

Funding

The authors thank the Research Foundation – Flanders (FWO Vlaanderen) for financial support (projects G087718N, G0D1521N, I006320N, GOH3816NAUHL, the Scientific Research Community ‘Supramolecular Chemistry and Materials’ (W000620N), and Ph.D. scholarship S. Paredis). The calculations were performed on the computers of the ‘Consortium des équipements de Calcul Intensif (CÉCI)’ ( http://www.ceci‐hpc.be ), including those of the ‘UNamur Technological Platform of High‐Performance Computing (PTCI)’ ( http://www.ptci.unamur.be ), for which we gratefully acknowledge financial support from the FNRS‐FRFC, the Walloon Region, and the University of Namur (Conventions No. GEQ U.G006.15, U.G018.19, U.G011.22, RW/GEQ2016, RW1610468, and RW2110213). A.P. Monkman is supported by EPSRC grant EP/T02240X/1. The authors thank the Research Foundation – Flanders (FWO Vlaanderen) for financial support (projects G087718N, G0D1521N, I006320N, GOH3816NAUHL, the Scientific Research Community ‘Supramolecular Chemistry and Materials’ (W000620N), and Ph.D. scholarship S. Paredis). The calculations were performed on the computers of the ‘Consortium des équipements de Calcul Intensif (CÉCI)’ (http://www.ceci-hpc.be), including those of the ‘UNamur Technological Platform of High-Performance Computing (PTCI)’ (http://www.ptci.unamur.be), for which we gratefully acknowledge financial support from the FNRS-FRFC, the Walloon Region, and the University of Namur (Conventions No. GEQ U.G006.15, U.G018.19, U.G011.22, RW/GEQ2016, RW1610468, and RW2110213). A.P. Monkman is supported by EPSRC grant EP/T02240X/1.

Keywords

donor-acceptor fluorophores
energy gap tuning
room temperature phosphorescence
time-resolved spectroscopy

Access to Document

10.1002/chem.202301369

Cite this

@article{361e1559dbb84c1d88ba85160fdcd600,

title = "Balanced Energy Gaps as a Key Design Rule for Solution-Phase Organic Room Temperature Phosphorescence",

abstract = "Metal-free organic emitters that display solution-phase room temperature phosphorescence (sRTP) remain exceedingly rare. Here, we investigate the structural and photophysical properties that support sRTP by comparing a recently reported sRTP compound (BTaz−Th−PXZ) to two novel analogous materials, replacing the donor group by either acridine or phenothiazine. The emissive triplet excited state remains fixed in all three cases, while the emissive charge-transfer singlet states (and the calculated paired charge-transfer T2 state) vary with the donor unit. While all three materials show dominant RTP in film, in solution different singlet-triplet and triplet-triplet energy gaps give rise to triplet-triplet annihilation followed by weak sRTP for the new compounds, compared to dominant sRTP throughout for the original PXZ material. Engineering both the sRTP state and higher charge-transfer states therefore emerges as a crucial element in designing emitters capable of sRTP.",

keywords = "donor-acceptor fluorophores, energy gap tuning, room temperature phosphorescence, time-resolved spectroscopy",

author = "Simon Paredis and Tom Cardeynaels and Suman Kuila and Jasper Deckers and {Van Landeghem}, Melissa and Koen Vandewal and Andrew Danos and Monkman, {Andrew P.} and Beno{\^i}t Champagne and Wouter Maes",

note = "Funding Information: The authors thank the Research Foundation – Flanders (FWO Vlaanderen) for financial support (projects G087718N, G0D1521N, I006320N, GOH3816NAUHL, the Scientific Research Community {\textquoteleft}Supramolecular Chemistry and Materials{\textquoteright} (W000620N), and Ph.D. scholarship S. Paredis). The calculations were performed on the computers of the {\textquoteleft}Consortium des {\'e}quipements de Calcul Intensif (C{\'E}CI){\textquoteright} ( http://www.ceci‐hpc.be ), including those of the {\textquoteleft}UNamur Technological Platform of High‐Performance Computing (PTCI){\textquoteright} ( http://www.ptci.unamur.be ), for which we gratefully acknowledge financial support from the FNRS‐FRFC, the Walloon Region, and the University of Namur (Conventions No. GEQ U.G006.15, U.G018.19, U.G011.22, RW/GEQ2016, RW1610468, and RW2110213). A.P. Monkman is supported by EPSRC grant EP/T02240X/1. Funding Information: The authors thank the Research Foundation – Flanders (FWO Vlaanderen) for financial support (projects G087718N, G0D1521N, I006320N, GOH3816NAUHL, the Scientific Research Community {\textquoteleft}Supramolecular Chemistry and Materials{\textquoteright} (W000620N), and Ph.D. scholarship S. Paredis). The calculations were performed on the computers of the {\textquoteleft}Consortium des {\'e}quipements de Calcul Intensif (C{\'E}CI){\textquoteright} (http://www.ceci-hpc.be), including those of the {\textquoteleft}UNamur Technological Platform of High-Performance Computing (PTCI){\textquoteright} (http://www.ptci.unamur.be), for which we gratefully acknowledge financial support from the FNRS-FRFC, the Walloon Region, and the University of Namur (Conventions No. GEQ U.G006.15, U.G018.19, U.G011.22, RW/GEQ2016, RW1610468, and RW2110213). A.P. Monkman is supported by EPSRC grant EP/T02240X/1. Publisher Copyright: {\textcopyright} 2023 Wiley-VCH GmbH.",

year = "2023",

month = jul,

day = "26",

doi = "10.1002/chem.202301369",

language = "English",

volume = "29",

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T1 - Balanced Energy Gaps as a Key Design Rule for Solution-Phase Organic Room Temperature Phosphorescence

AU - Paredis, Simon

AU - Cardeynaels, Tom

AU - Kuila, Suman

AU - Deckers, Jasper

AU - Van Landeghem, Melissa

AU - Vandewal, Koen

AU - Danos, Andrew

AU - Monkman, Andrew P.

AU - Champagne, Benoît

AU - Maes, Wouter

N1 - Funding Information: The authors thank the Research Foundation – Flanders (FWO Vlaanderen) for financial support (projects G087718N, G0D1521N, I006320N, GOH3816NAUHL, the Scientific Research Community ‘Supramolecular Chemistry and Materials’ (W000620N), and Ph.D. scholarship S. Paredis). The calculations were performed on the computers of the ‘Consortium des équipements de Calcul Intensif (CÉCI)’ ( http://www.ceci‐hpc.be ), including those of the ‘UNamur Technological Platform of High‐Performance Computing (PTCI)’ ( http://www.ptci.unamur.be ), for which we gratefully acknowledge financial support from the FNRS‐FRFC, the Walloon Region, and the University of Namur (Conventions No. GEQ U.G006.15, U.G018.19, U.G011.22, RW/GEQ2016, RW1610468, and RW2110213). A.P. Monkman is supported by EPSRC grant EP/T02240X/1. Funding Information: The authors thank the Research Foundation – Flanders (FWO Vlaanderen) for financial support (projects G087718N, G0D1521N, I006320N, GOH3816NAUHL, the Scientific Research Community ‘Supramolecular Chemistry and Materials’ (W000620N), and Ph.D. scholarship S. Paredis). The calculations were performed on the computers of the ‘Consortium des équipements de Calcul Intensif (CÉCI)’ (http://www.ceci-hpc.be), including those of the ‘UNamur Technological Platform of High-Performance Computing (PTCI)’ (http://www.ptci.unamur.be), for which we gratefully acknowledge financial support from the FNRS-FRFC, the Walloon Region, and the University of Namur (Conventions No. GEQ U.G006.15, U.G018.19, U.G011.22, RW/GEQ2016, RW1610468, and RW2110213). A.P. Monkman is supported by EPSRC grant EP/T02240X/1. Publisher Copyright: © 2023 Wiley-VCH GmbH.

PY - 2023/7/26

Y1 - 2023/7/26

N2 - Metal-free organic emitters that display solution-phase room temperature phosphorescence (sRTP) remain exceedingly rare. Here, we investigate the structural and photophysical properties that support sRTP by comparing a recently reported sRTP compound (BTaz−Th−PXZ) to two novel analogous materials, replacing the donor group by either acridine or phenothiazine. The emissive triplet excited state remains fixed in all three cases, while the emissive charge-transfer singlet states (and the calculated paired charge-transfer T2 state) vary with the donor unit. While all three materials show dominant RTP in film, in solution different singlet-triplet and triplet-triplet energy gaps give rise to triplet-triplet annihilation followed by weak sRTP for the new compounds, compared to dominant sRTP throughout for the original PXZ material. Engineering both the sRTP state and higher charge-transfer states therefore emerges as a crucial element in designing emitters capable of sRTP.

AB - Metal-free organic emitters that display solution-phase room temperature phosphorescence (sRTP) remain exceedingly rare. Here, we investigate the structural and photophysical properties that support sRTP by comparing a recently reported sRTP compound (BTaz−Th−PXZ) to two novel analogous materials, replacing the donor group by either acridine or phenothiazine. The emissive triplet excited state remains fixed in all three cases, while the emissive charge-transfer singlet states (and the calculated paired charge-transfer T2 state) vary with the donor unit. While all three materials show dominant RTP in film, in solution different singlet-triplet and triplet-triplet energy gaps give rise to triplet-triplet annihilation followed by weak sRTP for the new compounds, compared to dominant sRTP throughout for the original PXZ material. Engineering both the sRTP state and higher charge-transfer states therefore emerges as a crucial element in designing emitters capable of sRTP.

KW - donor-acceptor fluorophores

KW - energy gap tuning

KW - room temperature phosphorescence

KW - time-resolved spectroscopy

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VL - 29

JO - Chemistry: A European Journal

JF - Chemistry: A European Journal

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M1 - e202301369

ER -

Balanced Energy Gaps as a Key Design Rule for Solution-Phase Organic Room Temperature Phosphorescence

Abstract

Funding

Keywords

Access to Document

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Convention de collaboration/co-financement avec UHasselt

Equipment renewal for the Consortium des Equipements de Calcul Intensif (CECI)

High Performance Computing Technology Platform

Cite this

Balanced Energy Gaps as a Key Design Rule for Solution-Phase Organic Room Temperature Phosphorescence

Abstract

Funding

Keywords

Access to Document

Other files and links

Fingerprint

Projects

Convention de collaboration/co-financement avec UHasselt

Equipment renewal for the Consortium des Equipements de Calcul Intensif (CECI)

Equipment

High Performance Computing Technology Platform

Cite this