Electronic interplay on illuminated aqueous carbon nanohorn-porphyrin ensembles.
Electronic interplay on illuminated aqueous carbon nanohorn-porphyrin ensembles.
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DOI：
10.1021/jp064685m
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发表时间：
2006-09
期刊：
影响因子：
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通讯作者：
G. Pagona;Atula S. D. Sandanayaka;Y. Araki;Jing Fan;N. Tagmatarchis;M. Yudasaka;S. Iijima;O. Ito
中科院分区：
文献类型：
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作者：
G. Pagona;Atula S. D. Sandanayaka;Y. Araki;Jing Fan;N. Tagmatarchis;M. Yudasaka;S. Iijima;O. Ito
四阳离子水溶性卟啉(H(2)P(4+))通过pi-pi堆积作用固定在碳纳米角(CNH)的骨架上，而不破坏其pi-电子网络。用电子显微镜和光谱技术研究了CNH-H(2)P(4+)纳米体系的稳定水溶液。用稳态荧光发射光谱和时间分辨荧光发射光谱研究了CNH-H(2)P(4+)纳米系中H(2)P(4+)部分的有效荧光猝灭，表明光激发的H(2)P(4+)向CNH电荷分离。在甲基紫精(MV(2+))和空穴陷阱的存在下，CNH-H(2)P(4+)的光照射下观察到甲基紫精的还原物种的积累，这表明电子从最初形成的电荷分离态发生了迁移。瞬时吸收光谱进一步揭示了电荷分离态(CNH(*-))-(H(2)P(4+))(*+)在MV(2+)和空穴移位剂存在下被消耗，留下还原的甲基紫精等暂态物种。
Tetracationic water-soluble porphyrin (H(2)P(4+)) has been immobilized by pi-pi stacking interactions onto the skeleton of carbon nanohorns (CNH), without disrupting their pi-electronic network. The stable aqueous solution of the CNH-H(2)P(4+) nanoensemble was examined by both electron microscopy and spectroscopic techniques. The efficient fluorescence quenching of the H(2)P(4+) moiety in the CNH-H(2)P(4+) nanoensemble was probed by steady-state as well as time-resolved fluorescence emission spectroscopy, suggesting charge separation from the photoexcited H(2)P(4+) to CNH. In the presence of methyl viologen dication (MV(2+)) and a hole trap, accumulation of the reduced species of methyl viologen was observed by the photoillumination of CNH-H(2)P(4+), suggesting that the electron migration from the initially formed charge-separated state takes place. Transient absorption spectroscopy gave further insights on the transient species such as the charge-separated state (CNH(*-))-(H(2)P(4+))(*+), which was consumed in the presence of MV(2+) and hole shifter, leaving the reduced methyl viologen.