Feng Jiale, Hosseinabadi Parisa, de Clercq Damon M, Carwithen Ben P, Nielsen Michael P, Brett Matthew W, Prasad Shyamal K K, Farahani Adam A D, Li Hsiu L, Sanders Samuel N, Beves Jonathon E, Ekins-Daukes N J, Cole Jared H, Thordarson Pall, Huang David M, Tayebjee Murad J Y, Schmidt Timothy W
ARC Centre of Excellence in Exciton Science, School of Chemistry, UNSW Sydney, Sydney, New South Wales, Australia.
School of Photovoltaic and Renewable Energy Engineering, UNSW Sydney, Sydney, New South Wales, Australia.
Nat Chem. 2024 Nov;16(11):1861-1867. doi: 10.1038/s41557-024-01591-0. Epub 2024 Jul 25.
The photophysical processes of singlet fission and triplet fusion have numerous emerging applications. They involve the separation of a photo-generated singlet exciton into two dark triplet excitons and the fusion of two dark triplet excitons into an emissive singlet exciton, respectively. The role of the excimer state and the nature of the triplet-pair state in these processes have been a matter of contention. Here we analyse the room temperature time-resolved emission of a neat liquid singlet fission chromophore and show that it exhibits three spectral components: two that correspond to the bright singlet and excimer states and a third component that becomes more prominent during triplet fusion. This spectrum is enhanced by magnetic fields, confirming its origins in the recombination of weakly coupled triplet pairs. It is thus attributed to a strongly coupled triplet pair state. These observations unite the view that there is an emissive intermediate in singlet fission and triplet fusion, distinct from the broad, unstructured excimer emission.
单线态裂变和三线态融合的光物理过程有众多新兴应用。它们分别涉及将光生单线态激子分离为两个暗三线态激子以及将两个暗三线态激子融合为一个发光单线态激子。在这些过程中，准分子态的作用以及三线态对态的性质一直存在争议。在此，我们分析了一种纯液体单线态裂变发色团在室温下的时间分辨发射，并表明它呈现出三个光谱成分：两个对应于明亮单线态和准分子态，第三个成分在三线态融合过程中变得更加显著。该光谱会因磁场增强，证实其源于弱耦合三线态对的复合。因此，它被归因于强耦合三线态对态。这些观察结果统一了这样一种观点，即单线态裂变和三线态融合中存在一种发光中间体，不同于宽泛、无结构的准分子发射。
