Structural relaxation inthe singlet excited state of star-shapedoligofluorenes having a truxene or isotruxene asa core
Structural relaxation inthe singlet excited state of star-shapedoligofluorenes having a truxene or isotruxene asa core
复制标题
以聚芴或异聚芴为核心的星形低聚芴在单重激发态的结构弛豫
DOI：
10.1021/jp2074336
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
TetsuroMajima
中科院分区：
文献类型：
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作者：
Mamoru Fujitsuka;Dae Won Cho;TetsuroMajima
低聚芴类化合物因其优异的荧光性能而受到广泛关注。为了详细了解激发态的性质，超快过程必须澄清。在这里，我们已经研究了在单重激发态的星形低聚芴与truxene或isotruxene核心，其中低聚芴（n= 1-4）连接的结构弛豫。瞬态吸收峰随激发时间发生红移。在皮秒域的荧光衰减曲线显示除了对应于单重激发态寿命的组件的快速组件。这些超快现象可以归因于结构弛豫，即，平面化，在单重激发态。基于含时密度泛函理论的理论计算支持平坦化过程。此外，双光子吸收截面的星状低聚芴的核心的依赖关系已被阐明。
Oligofluorenes attract wide attention due to their excellent fluorescent properties. For the detailed understanding of the excited state properties, ultrafast processes have to be clarified. Here, we have investigated the structural relaxation in the singlet excited state of star-shaped oligofluorenes with a truxene or isotruxene core, to which oligofluorenes (n= 1–4) were attached. The transient absorption peak showed red-shift with time upon excitation. The fluorescence decay profiles in the picosecond domain showed the fast component in addition to the component corresponding to the singlet excited state lifetime. These ultrafast phenomena can be attributed to the structural relaxation, i.e., planarization, in the singlet excited state. The planarization process was supported by the theoretical calculation based on the time-dependent density functional theory. Furthermore, dependence of two-photon absorption cross section on the core of the star-shaped oligofluorene has been elucidated.