Temperature dependency of energy shift of excitonic states in a donor–acceptor type TADF molecule

Abstract In recent years, thermally activated delayed fluorescence (TADF) has attracted intense attention owing to its straightforward application to high-efficiency organic light-emitting diodes. Further, to develop high-performance TADF materials, many researchers have designed novel molecules tha...

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Main Authors: Youichi Tsuchiya, Keito Mizukoshi, Masaki Saigo, Tomohiro Ryu, Keiko Kusuhara, Kiyoshi Miyata, Ken Onda, Chihaya Adachi
Format: Article
Language:English
Published: Nature Portfolio 2025-05-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-59910-z
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author Youichi Tsuchiya
Keito Mizukoshi
Masaki Saigo
Tomohiro Ryu
Keiko Kusuhara
Kiyoshi Miyata
Ken Onda
Chihaya Adachi
author_facet Youichi Tsuchiya
Keito Mizukoshi
Masaki Saigo
Tomohiro Ryu
Keiko Kusuhara
Kiyoshi Miyata
Ken Onda
Chihaya Adachi
author_sort Youichi Tsuchiya
collection DOAJ
description Abstract In recent years, thermally activated delayed fluorescence (TADF) has attracted intense attention owing to its straightforward application to high-efficiency organic light-emitting diodes. Further, to develop high-performance TADF materials, many researchers have designed novel molecules that have a small energy gap between the lowest excited singlet and triplet states ( $$\Delta {E}_{{ST}}$$ Δ E S T ), and detailed analysis suggests a significant contribution of higher-lying excited states for spin flipping processes. In this study, we demonstrate a peculiar thermal behaviour of emission decay of a donor–acceptor type TADF molecule, TMCz-BO, which seems like thermal deactivation of delayed fluorescence that can be explained without a negative $$\Delta {E}_{{ST}}$$ Δ E S T by comprehensive kinetic analysis across various temperatures and solvents. While the activation energy has previously been treated as being temperature-independent, we stress that it should be a dynamic parameter affected by changing the solvent-solute interaction with the environmental temperature, especially in the case of a small energy gap.
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spelling doaj-art-052c6c59fad54d9fbad25b2188c868302025-08-20T01:53:14ZengNature PortfolioNature Communications2041-17232025-05-011611810.1038/s41467-025-59910-zTemperature dependency of energy shift of excitonic states in a donor–acceptor type TADF moleculeYouichi Tsuchiya0Keito Mizukoshi1Masaki Saigo2Tomohiro Ryu3Keiko Kusuhara4Kiyoshi Miyata5Ken Onda6Chihaya Adachi7Center for Organic Photonics and Electronics Research (OPERA), Kyushu UniversityCenter for Organic Photonics and Electronics Research (OPERA), Kyushu UniversityDepartment of Chemistry, Faculty of Science, Kyushu UniversityDepartment of Chemistry, Faculty of Science, Kyushu UniversityCenter for Organic Photonics and Electronics Research (OPERA), Kyushu UniversityDepartment of Chemistry, Faculty of Science, Kyushu UniversityDepartment of Chemistry, Faculty of Science, Kyushu UniversityCenter for Organic Photonics and Electronics Research (OPERA), Kyushu UniversityAbstract In recent years, thermally activated delayed fluorescence (TADF) has attracted intense attention owing to its straightforward application to high-efficiency organic light-emitting diodes. Further, to develop high-performance TADF materials, many researchers have designed novel molecules that have a small energy gap between the lowest excited singlet and triplet states ( $$\Delta {E}_{{ST}}$$ Δ E S T ), and detailed analysis suggests a significant contribution of higher-lying excited states for spin flipping processes. In this study, we demonstrate a peculiar thermal behaviour of emission decay of a donor–acceptor type TADF molecule, TMCz-BO, which seems like thermal deactivation of delayed fluorescence that can be explained without a negative $$\Delta {E}_{{ST}}$$ Δ E S T by comprehensive kinetic analysis across various temperatures and solvents. While the activation energy has previously been treated as being temperature-independent, we stress that it should be a dynamic parameter affected by changing the solvent-solute interaction with the environmental temperature, especially in the case of a small energy gap.https://doi.org/10.1038/s41467-025-59910-z
spellingShingle Youichi Tsuchiya
Keito Mizukoshi
Masaki Saigo
Tomohiro Ryu
Keiko Kusuhara
Kiyoshi Miyata
Ken Onda
Chihaya Adachi
Temperature dependency of energy shift of excitonic states in a donor–acceptor type TADF molecule
Nature Communications
title Temperature dependency of energy shift of excitonic states in a donor–acceptor type TADF molecule
title_full Temperature dependency of energy shift of excitonic states in a donor–acceptor type TADF molecule
title_fullStr Temperature dependency of energy shift of excitonic states in a donor–acceptor type TADF molecule
title_full_unstemmed Temperature dependency of energy shift of excitonic states in a donor–acceptor type TADF molecule
title_short Temperature dependency of energy shift of excitonic states in a donor–acceptor type TADF molecule
title_sort temperature dependency of energy shift of excitonic states in a donor acceptor type tadf molecule
url https://doi.org/10.1038/s41467-025-59910-z
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