Photoabsorbance of supported metal clusters: ab initio density matrix and model studies of large Ag clusters on Si surfaces
Photoabsorbance of supported metal clusters: ab initio density matrix and model studies of large Ag clusters on Si surfaces
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负载金属簇的光吸收：从头算密度矩阵和 Si 表面上大型银簇的模型研究
DOI：
10.1039/d2cp04922h
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发表时间：
2023
影响因子：
3.3
通讯作者：
Micha, David A.
中科院分区：
文献类型：
--
作者：
Vazhappilly, Tijo;Kilin, Dmitri S.;Micha, David A.
由固体表面支撑的具有10到100个原子的金属团簇显示出典型的分子电子结构，需要从原子结构开始进行从头算处理，并且它们还可以显示类似于金属固体中等离子体的集体电子现象。我们采用两种不同密度泛函(PBE和混合HSE06)的从头算电子结构结果和耗散光动力学的约化密度矩阵处理方法，计算了大的Ag团簇AgN，N=33，37(开壳层)和N=32，34(封闭层)的光吸收系数，并形成了纳米结构表面。对于这两个泛函，光吸收的结果是完全不同的，这里给出了利用轨道和来自混合泛函的能量来计算光吸收的结果，并给出了正确的能带宽度。银团簇在硅上的吸收增加了光吸收相对于光子能量的很大百分比，峰值增加出现在与局域等离子体相对应的光子能量区域。目前的金属团簇足够大，可以用其介质的连续介电处理进行建模。给出了一个介观Drude-Lorentz模型，该模型适用于目前的结构，并解释了我们的结果。计算的等离子体激元能量范围与太阳光子能量范围重叠，使得目前的结构和性质与太阳光吸收和光催化的应用有关。
Metal clusters with 10 to 100 atoms supported by a solid surface show electronic structure typical of molecules and require ab initio treatments starting from their atomic structure, and they also can display collective electronic phenomena similar to plasmons in metal solids. We have employed ab initio electronic structure results from two different density functionals (PBE and the hybrid HSE06) and a reduced density matrix treatment of the dissipative photodynamics to calculate light absorbance by the large Ag clusters AgN, N = 33, 37(open shell) and N = 32, 34 (closed shell), adsorbed at the Si(111) surface of a slab, and forming nanostructured surfaces. Results on light absorption are quite different for the two functionals, and are presented here for light absorbances using orbitals and energies from the hybrid functional giving correct energy band gaps. Absorption of Ag clusters on Si increases light absorbance versus photon energy by large percentages, with peak increases found in regions of photon energies corresponding to localized plasmons. The present metal clusters are large enough to allow for modelling with continuum dielectric treatments of their medium. A mesoscopic Drude–Lorentz model is presented in a version suitable for the present structures, and provides an interpretation of our results. The calculated range of plasmon energies overlaps with the range of solar photon energies, making the present structures and properties relevant to applications to solar photoabsorption and photocatalysis.