Excited state dynamics and photophysics of aggregated dye chromophores in solution
Excited state dynamics and photophysics of aggregated dye chromophores in solution
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溶液中聚集染料发色团的激发态动力学和光物理学
DOI：
10.1063/1.449275
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发表时间：
1985
影响因子：
4.4
通讯作者：
T. Gillbro
中科院分区：
文献类型：
--
作者：
V. Sundström;T. Gillbro
本文用皮秒吸收光谱研究了单体和聚集态二乙基硫代双胍碘化物（DTDCI）的激发态弛豫过程。强相互作用的二聚体和三聚体的发色团被发现有非常快速和有效的无辐射过程，其速率是独立的温度和粘度，但强烈依赖于溶剂的介电常数。这些结果和共价连接的bis-DTDCI二聚体的类似结果使我们能够确定弛豫机制，并提出一个解释观察结果的理论模型。我们认为，无辐射的过程是由聚集体的单元之间的非常强的偶极-偶极相互作用引起的;类比所谓的介质诱导的无辐射的过程也作出了。聚集染料中的弛豫速率的估计值与测量值在数量级上一致。
We have studied the excited state relaxation processes of monomeric and aggregated diethylthiadicarbocyanine iodide (DTDCI) by means of picosecond absorption spectroscopy. The strongly interacting chromophores of dimers and trimers are found to have very fast and efficient radiationless processes, whose rates are independent of temperature and viscosity, but strongly dependent on solvent dielectric constant. These results and similar ones for the covalently linked bis‐DTDCI dimer allow us to identify the relaxation mechanism and suggest a theoretical model which accounts for the observations. We suggest that the radiationless processes are induced by the very strong dipole–dipole interactions between the units of the aggregate; analogies to the so called medium induced radiationless processes are also made. Estimates of the relaxation rates in the aggregated dye yields values which are in order‐of‐magnitude agreement with the measured values.