Femtosecond excited-state dynamics of fullerene-C60 nanoparticles in water
Femtosecond excited-state dynamics of fullerene-C60 nanoparticles in water
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DOI：
10.1039/c7cp06746a
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发表时间：
2018-01-14
影响因子：
3.3
通讯作者：
Asahi, Tsuyoshi
中科院分区：
文献类型：
--
作者：
Ishibashi, Yukihide;Arinishi, Miya;Asahi, Tsuyoshi
利用飞秒瞬态吸收光谱研究了分散在纯水中的平均粒径为50 nm的富勒烯-C-60纳米颗粒（nC（60））的飞秒激发态动力学。采用飞秒激光350 nm和420 nm激发，首次直接观察到固体C-60分子间的电荷转移（CT）激发态，其本征寿命为0.35 ps，CT激发态通过成对电荷复合弛豫到Si和激子的局域激发态或直接弛豫到基态.我们还研究了CT激发态动力学的激光能量密度依赖性。在高激光能量密度下，激发后立即观察到相邻CT激发态之间的相互作用。这种相互作用通过电荷在成对的CT对或相邻的CT激发态之间的复合而消失，寿命为0.45 ps。在此之后，局部激发的S-1态衰减与几ps的寿命无关的注量。本文详细讨论了紫外光激发产生分子间CT激发态的机理和动力学。
Femtosecond excited-state dynamics of fullerene-C-60 nanoparticles (nC(60)) having a mean size of 50 nm dispersed in pure water was studied by means of femtosecond transient absorption spectroscopy. The intermolecular charge-transfer (CT) excited state in solid C-60 was directly and firstly observed by femtosecond 350 nm and 420 nm excitations, and its intrinsic lifetime of 0.35 ps was found. The CT excited state relaxed to the locally excited Si state and excimers or directly to the ground state through geminate charge recombination. We also examined the laser fluence dependence of the CT excited-state dynamics. At a high laser fluence, the mutual interactions between neighboring CT excited states were observed immediately after the excitation. The interaction disappeared through the charge recombination in the geminate CT pair or between the neighboring CT excited states with a lifetime of 0.45 ps. After that, the locally excited S-1 state decayed with a few ps lifetime independent of the fluence. In this paper, the mechanism and dynamics of the intermolecular CT excited state generated by UV light excitation is discussed in detail.