Ma Jie, Wang Zhi, Wang Lin-Wang
Joint Center for Artificial Photosynthesis and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Nat Commun. 2015 Dec 17;6:10107. doi: 10.1038/ncomms10107.
Plasmon-generated hot carriers are used in photovoltaic or photochemical applications. However, the interplays between the plasmon and single-particle excitations in nanosystems have not been theoretically addressed using ab initio methods. Here we show such interplays in a Ag55 nanocluster using real-time time-dependent density functional theory simulations. We find that the disappearance of the zero-frequency peak in the Fourier transform of the band-to-band transition coefficient is a hallmark of the plasmon. We show the importance of the d-states for hot-carrier generations. If the single-particle d-to-s excitations are resonant to the plasmon frequency, the majority of the plasmon energy will be converted into hot carriers, and the overall hot-carrier generation is enhanced by the plasmon; if such resonance does not exist, we observe an intriguing Rabi oscillation between the plasmon and hot carriers. Phonons play a minor role in plasmonic dynamics in such small systems. This study provides guidance on improving plasmonic applications.
表面等离激元产生的热载流子被用于光伏或光化学应用中。然而，纳米系统中表面等离激元与单粒子激发之间的相互作用尚未通过从头算方法进行理论研究。在此，我们使用实时含时密度泛函理论模拟展示了Ag55纳米团簇中的这种相互作用。我们发现带间跃迁系数傅里叶变换中零频峰的消失是表面等离激元的一个标志。我们展示了d态对热载流子产生的重要性。如果单粒子d到s激发与表面等离激元频率共振，大部分表面等离激元能量将转化为热载流子，并且表面等离激元会增强整体热载流子的产生；如果不存在这种共振，我们观察到表面等离激元和热载流子之间有趣的拉比振荡。在如此小的系统中，声子在表面等离激元动力学中起次要作用。这项研究为改进表面等离激元应用提供了指导。
