DNA-Templated Aggregates of Strongly Coupled Cyanine Dyes: Nonradiative Decay Governs Exciton Lifetimes
DNA-Templated Aggregates of Strongly Coupled Cyanine Dyes: Nonradiative Decay Governs Exciton Lifetimes
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DOI：
10.1021/acs.jpclett.9b00404
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发表时间：
2019-05-16
影响因子：
5.7
通讯作者：
Pensack, Ryan D.
中科院分区：
文献类型：
--
作者：
Huff, Jonathan S.;Davis, Paul H.;Pensack, Ryan D.
分子激子用于多种应用，包括光捕获、光电子学和纳米级计算。通过染料与 DNA 模板共价连接来控制聚集是一种很有前途的聚集组装技术，可以设计扩展的染料网络。然而，关于 DNA 模板染料聚集体中激子动力学的研究很少。我们报告了两种基于花青的染料聚集体（一种 J 类二聚体和一种 H 类四聚体）的时间分辨激发态动力学测量，它们是通过共价连接染料的 DNA 模板形成的。时间分辨荧光和瞬态吸收表明，内部转换形式的非辐射衰变主导了聚集体基态恢复动力学，聚集体的单线态激子寿命约为数十皮秒，而单体的单线态激子寿命约为纳秒。这些结果凸显了在未来 DNA 模板染料聚集体设计中规避非辐射衰变途径的重要性。
Molecular excitons are used in a variety of applications including light harvesting, optoelectronics, and nanoscale computing. Controlled aggregation via covalent attachment of dyes to DNA templates is a promising aggregate assembly technique that enables the design of extended dye networks. However, there are few studies of exciton dynamics in DNA-templated dye aggregates. We report time-resolved excited-state dynamics measurements of two cyanine-based dye aggregates, a J-like dimer and an H-like tetramer, formed through DNA-templating of covalently attached dyes. Time-resolved fluorescence and transient absorption indicate that nonradiative decay, in the form of internal conversion, dominates the aggregate ground state recovery dynamics, with singlet exciton lifetimes on the order of tens of picoseconds for the aggregates versus nanoseconds for the monomer. These results highlight the importance of circumventing nonradiative decay pathways in the future design of DNA-templated dye aggregates.