Enhancement of the Photocurrent of a Single Photosystem I Complex by the Localized Plasmon of a Gold Nanorod
Enhancement of the Photocurrent of a Single Photosystem I Complex by the Localized Plasmon of a Gold Nanorod
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DOI：
10.1021/jacs.1c04691
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发表时间：
2021-08-10
影响因子：
15
通讯作者：
Vacha, Martin
中科院分区：
文献类型：
--
作者：
Furuya, Ryotaro;Omagari, Shun;Vacha, Martin
采用导电原子力显微镜（AFM）和共聚焦荧光显微镜相结合的方法，测量了位于单金纳米棒（aunr）附近的单三聚体光系统I （PSI）配合物的光电流。同时激发PSI和AuNR纵向等离子体模式，并检测来自单个PSI的光电流与单个AuNR位置的关系，使我们能够深入了解等离子体诱导的现象，否则在集合实验中是无法实现的。我们观察到局域等离子体对光电流的增强平均为2.9倍，最大增强值可达8倍。利用激发激光的偏振选择性激发纵向等离子体模式，实现了光电流增强的可控开关。增强的程度取决于PSI和aunr之间的距离，这表明除了吸收增强外，还有一个直接影响电子传递过程的附加增强机制。本研究为等离子体增强光电流的分子机制提供了更深入的见解，不仅在PSI中，而且在其他系统中也有可能。
A combination of conductive atomic force microscopy (AFM) and confocal fluorescence microscopy was used to measure photocurrents passing through single trimeric photosytem I (PSI) complexes located in the vicinity of single gold nanorods (AuNRs). Simultaneous excitation of PSI and of the AuNR longitudinal plasmon mode and detection of photocurrents from individual PSI in relation to the position of single AuNRs enable insight into plasmon-induced phenomena that are otherwise inaccessible in ensemble experiments. We have observed photocurrent enhancement by the localized plasmons by a factor of 2.9 on average, with maximum enhancement values of up to 8. Selective excitation of the longitudinal plasmon modes by the polarization of the excitation laser enables controllable switch-on of the photocurrent enhancement. The dependence of the extent of enhancement on the distance between PSI and AuNRs indicates that, apart from the enhancement of absorption, there is an additional enhancement mechanism affecting directly the electron transport process. The present study provides deeper insight into the molecular mechanisms of plasmon-enhanced photocurrents, not only in PSI but also potentially in other systems as well.