Zhou Meng, Zeng Chenjie, Sfeir Matthew Y, Cotlet Mircea, Iida Kenji, Nobusada Katsuyuki, Jin Rongchao
Department of Chemistry, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States.
Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States.
J Phys Chem Lett. 2017 Sep 7;8(17):4023-4030. doi: 10.1021/acs.jpclett.7b01597. Epub 2017 Aug 15.
Understanding the correlation between the atomic structure and optical properties of gold nanoclusters is essential for exploration of their functionalities and applications involving light harvesting and electron transfer. We report the femto-nanosecond excited state dynamics of a periodic series of face-centered cubic (FCC) gold nanoclusters (including Au, Au, Au, and Au), which exhibit a set of unique features compared with other similar sized clusters. Molecular-like ultrafast S → S internal conversions (i.e., radiationless electronic transitions) are observed in the relaxation dynamics of FCC periodic series. Excited-state dynamics with near-HOMO-LUMO gap excitation lacks ultrafast decay component, and only the structural relaxation dominates in the dynamical process, which proves the absence of core-shell relaxation. Interestingly, both the relaxation of the hot carriers and the band-edge carrier recombination become slower as the size increases. The evolution in excited-state properties of this FCC series offers new insight into the structure-dependent properties of metal nanoclusters, which will benefit their optical energy harvesting and photocatalytic applications.
了解金纳米团簇的原子结构与光学性质之间的相关性，对于探索其涉及光捕获和电子转移的功能及应用至关重要。我们报道了一系列面心立方（FCC）金纳米团簇（包括Au、Au、Au和Au）的飞秒-纳秒激发态动力学，与其他类似尺寸的团簇相比，它们展现出一组独特的特征。在FCC周期系列的弛豫动力学中观察到类似分子的超快S→S内转换（即无辐射电子跃迁）。近HOMO-LUMO能隙激发的激发态动力学缺乏超快衰减成分，并且在动力学过程中仅结构弛豫占主导，这证明不存在核壳弛豫。有趣的是，随着尺寸增加，热载流子的弛豫和带边载流子复合都变得更慢。该FCC系列激发态性质的演变，为金属纳米团簇的结构依赖性性质提供了新的见解，这将有利于它们的光能捕获和光催化应用。
