Here, we have synthesized rod and flake shaped morphology of porphyrin aggregates from 5, 10, 15, 20‐tetra (4‐n‐octyloxyphenyl) porphyrin (4‐opTPP) molecule which are evident from scanning electron microscopy (SEM). The formation of J‐type aggregation is evident from steady state and time‐resolved fluorescence spectroscopic studies. Ultrafast transient absorption spectroscopic studies reveal that the excited state lifetime is controlled by the morphology and the time constant for S₁→S₀ relaxation changes from 3.05 ps to 744 ps with changing the shape from rod to flake, respectively. In spite of similar exciton coupling energy in both the aggregates, the flake shaped aggregates undergo a faster exciton relaxation process and the non‐radiative relaxation channels are found to depend on the shape of aggregates. The fundamental understanding of morphology controlled ultrafast relaxation processes of aggregated porphyrin is important for designing efficient light harvesting devices.

中文翻译：

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聚集卟啉的形态控制超快弛豫过程研究

在这里，我们从5、10、15、20-四（4-正辛基氧苯基）卟啉（4-opTPP）分子合成了卟啉聚集体的棒状和片状形态，这从扫描电子显微镜（SEM）可以明显看出。从稳态和时间分辨荧光光谱研究中可以明显看出J型聚集体的形成。超快瞬态吸收光谱研究表明，激发态的寿命受S ₁ →S ₀的形态和时间常数控制从棒状到薄片状，弛豫从3.05 ps变为744 ps。尽管两种骨料中的激子耦合能相似，但片状骨料经历了更快的激子弛豫过程，并且发现非辐射弛豫通道取决于骨料的形状。对聚集的卟啉的形态学控制的超快弛豫过程的基本理解对于设计有效的光收集装置很重要。