Tsuchiya Youichi, Mizukoshi Keito, Saigo Masaki, Ryu Tomohiro, Kusuhara Keiko, Miyata Kiyoshi, Onda Ken, Adachi Chihaya
Center for Organic Photonics and Electronics Research (OPERA), Kyushu University, Nishi, Fukuoka, Japan.
Department of Applied Chemistry, Kyushu University, Nishi, Fukuoka, Japan.
Nat Commun. 2025 May 23;16(1):4815. doi: 10.1038/s41467-025-59910-z.
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 ( ), 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 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.
近年来，热激活延迟荧光（TADF）因其在高效有机发光二极管中的直接应用而备受关注。此外，为了开发高性能的TADF材料，许多研究人员设计了新型分子，这些分子在最低激发单重态和三重态之间具有较小的能隙（ ），详细分析表明，较高激发态对自旋翻转过程有显著贡献。在本研究中，我们展示了供体-受体型TADF分子TMCz-BO发射衰减的一种特殊热行为，这种行为类似于延迟荧光的热失活，通过在不同温度和溶剂下的综合动力学分析，可以在没有负 的情况下进行解释。虽然活化能以前被视为与温度无关，但我们强调，它应该是一个动态参数，会受到环境温度下溶剂-溶质相互作用变化的影响，特别是在能隙较小的情况下。
