Annihilation of singlet excitons in J aggregates of pseudoisocyanine (PIC) studied by pico‐ and subpicosecond spectroscopy
Annihilation of singlet excitons in J aggregates of pseudoisocyanine (PIC) studied by pico‐ and subpicosecond spectroscopy
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通过皮秒和亚皮秒光谱研究准异花青 (PIC) J 聚集体中单线态激子的湮灭
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发表时间：
1988
期刊：
影响因子：
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通讯作者：
A. Piskarskas
中科院分区：
文献类型：
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作者：
V. Sundström;T. Gillbro;R. Gadonas;A. Piskarskas
通过皮秒和亚皮秒吸收光谱以及积分荧光产率测量研究了PIC的J聚集体的激发态动力学。这些测量结果表明，寿命和荧光产额强烈依赖于激发脉冲强度。在相对高的光强度（1014光子cm-2脉冲-1）下，S1的寿命基本上是脉冲限制的（<1 ps），荧光产率非常低。在降低光强度时，观察到激发态寿命和荧光产率逐渐增加。在非常低的激发强度（1010光子cm−2脉冲−1）下，观察到400 ps的单指数寿命。在中等强度下，激发态衰减是强烈的非指数衰减。所观察到的激发态动力学的强度依赖性归因于高移动的单重态激子之间的有效激子-激子湮灭。通过应用双分子激子anni的表达式。
The excited‐state dynamics of J aggregates of PIC have been studied by means of picosecond and subpicosecond absorption spectroscopy as well as integrated fluorescence yield measurements. The results of these measurements show that both the lifetime and the fluorescence yield are strongly dependent on excitation pulse intensity. At relatively high light intensity (1014 photons cm−2 pulse−1) the S1 lifetime is essentially pulse limited (<1 ps) and the fluorescence yield is very low. Upon decreasing the light intensity a gradual increase of the excited‐state lifetime and fluorescence yield is observed. At very low excitation intensity (1010 photons cm−2 pulse−1) a single exponential lifetime of 400 ps is observed. At intermediate intensities the excited‐state decay is strongly nonexponential. The observed intensity dependence of the excited‐state dynamics is attributed to efficient exciton–exciton annihilation between the highly mobile singlet excitons. By applying an expression for bimolecular exciton anni...