Imperiale Christian J, Green Philippe B, Miller Ethan G, Damrauer Niels H, Wilson Mark W B
Department of Chemistry , University of Toronto , Toronto , Ontario M5S3H6 , Canada.
Department of Chemistry and Biochemistry , University of Colorado, Boulder , Boulder , Colorado 80302 , United States.
J Phys Chem Lett. 2019 Dec 5;10(23):7463-7469. doi: 10.1021/acs.jpclett.9b03115. Epub 2019 Nov 21.
We demonstrate that a structurally rigid, weakly coupled molecular dimer can replace traditional monomeric annihilators for triplet fusion upconversion (TUC) in solution by observing emitted photons (λ = 540 nm) from a norbornyl-bridged tetracene homodimer following excitation of a triplet sensitizer at λ = 730 nm. Intriguingly, steady-state spectroscopy, kinetic simulations, and Stern-Volmer quenching experiments show that the dimer exhibits qualitatively different photophysics than its parent monomer: it is less effective at diffusion-mediated triplet exciton transfer, but it fuses extracted triplets more efficiently. Our results support the development of composite triplet-fusion platforms that go beyond diffusion-mediated triplet extraction, ultimately circumventing the concentration dependence of solution-phase TUC.
我们通过观察在λ = 730 nm激发三线态敏化剂后，降冰片烯桥连的并四苯同二聚体发射的光子（λ = 540 nm），证明了一种结构刚性、弱耦合的分子二聚体可以在溶液中替代传统的单体湮灭剂用于三线态融合上转换（TUC）。有趣的是，稳态光谱、动力学模拟和斯特恩-沃尔默猝灭实验表明，该二聚体表现出与其母体单体在性质上不同的光物理性质：它在扩散介导的三线态激子转移方面效率较低，但它能更有效地融合提取的三线态。我们的结果支持了复合三线态融合平台的开发，该平台超越了扩散介导的三线态提取，最终规避了溶液相TUC对浓度的依赖性。
