Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, 43124 Parma, Italy.
Department of Physics, Durham University, South Road, Durham DH1 3LE, U.K.
J Am Chem Soc. 2022 Aug 24;144(33):15211-15222. doi: 10.1021/jacs.2c05537. Epub 2022 Aug 9.
We present a detailed and comprehensive picture of the photophysics of thermally activated delayed fluorescence (TADF). The approach relies on a few-state model, parametrized on a prototypical TADF dye, that explicitly accounts for the nonadiabatic coupling between electrons and vibrational and conformational motion, crucial to properly address (reverse) intersystem crossing rates. The Onsager model is exploited to account for the medium polarity and polarizability, with careful consideration of the different time scales of relevant degrees of freedom. TADF photophysics is then quantitatively addressed in a coherent and exhaustive approach that accurately reproduces the complex temporal evolution of emission spectra in liquid solvents as well as in solid organic matrices. The different rigidity of the two environments is responsible for the appearance in matrices of important inhomogeneous broadening phenomena that are ascribed to the intertwined contribution from (quasi)static conformational and dielectric disorder.
我们呈现了热激活延迟荧光（TADF）光物理的详细和全面的图景。该方法依赖于一个少态模型，该模型参数化于一个典型的 TADF 染料，明确考虑了电子与振动和构象运动之间的非绝热耦合，这对于正确处理（反向）系间窜越速率至关重要。利用 Onsager 模型来解释介质的极性和极化率，并仔细考虑相关自由度的不同时间尺度。然后，以连贯和详尽的方式定量处理 TADF 光物理，准确再现了液体溶剂和固体有机基质中发射光谱的复杂时间演化。两种环境的不同刚性导致了在基质中出现重要的非均匀展宽现象，这些现象归因于（准）静态构象和介电无序的交织贡献。
