Hot electrons generated from the decay of localized surface plasmons in metallic nanostructures have the potential to transform photocatalysis, photodetection and other optoelectronic applications. However, the understanding of hot-carrier generation in realistic nanostructures, in particular the relative importance of interband and intraband transitions, remains incomplete. Here we report theoretical predictions of hot-carrier generation rates in spherical nanoparticles of the noble metals silver, gold and copper with diameters up to 30 nanometers obtained from a novel atomistic linear-scaling approach. As the nanoparticle size increases the relative importance of interband transitions from d-bands to sp-bands relative to surface-enabled sp-band to sp-band transitions increases. We find that the hot-hole generation rate is characterized by a peak at the onset of the d-bands, while the position of the corresponding peak in the hot-electron distribution can be controlled through the illumination frequency. In contrast, intraband transitions give rise to hot electrons, but relatively cold holes. Importantly, increasing the dielectric constant of the environment removes hot carriers generated from interband transitions, while increasing the number of hot carriers from intraband transitions. The insights resulting from our work enable the design of nanoparticles for specific hot-carrier applications through their material composition, size and dielectric environment.
Full ab initio band structure analysis of interband and intraband contributions for third harmonic generation coefficient of bulk silicon: implementation and application of the sum-over-states
Size and temperature dependent intraband optical studies of heavily n-doped PbS quantum dot solids
通过重掺杂，胶体量子点（CQD）中带内跃迁的稳态访问允许在带隙以下的能量处利用电磁波谱。CQD带内光电子学为廉价的中长波长红外光电探测器和发光器件开辟了一条新的道路，这些器件目前主要采用外延材料。作为一个新的实验研究领域，对量子点带内跃迁的基本性质的深入研究还很缺乏。本文研究了重掺杂PbS量子点（QD）薄膜的带内跃迁随尺寸和温度的变化。我们测量的带内跃迁的吸收系数是在$10^4$ cm $^{-1}$的顺序，这是可比的带间吸收系数的值。此外，我们确定的带内跃迁的振子强度的大小依赖性。我们证明了带内能量与温度的负相关性，相反的带间跃迁的正相关性。
Conventional and Acoustic Surface Plasmons on Noble Metal Surfaces: A Time-dependent Density Functional Theory Study
采用第一性原理计算方法研究了Cu、Ag和Au（111）表面的常规表面等离子体和声学表面等离子体。通过比较局域密度近似和轨道相关交换相关（xc）势的结果（该势改善了$d$带的位置和宽度），研究了$s-d$带间跃迁对两种类型等离子体激元的影响。用后者xc势计算的等离子体色散与电子能量损失谱（EELS）实验吻合得很好。对于CSP和ASP，对于等离子体激元能量，发现Cu $<$ Au $<$ Ag的相同趋势，并且归因于从Cu到Au和Ag的带间跃迁的减少的屏蔽。然而，ASP的这种趋势与先前的模型预测相矛盾。虽然ASP在EELS中被视为弱特征，但它可以在静态和动态介电能带结构中被清楚地识别。
Plasmonic excitations in noble metals: The case of Ag
通过{ \it ab initio}计算和一个简单的模型描述了贵金属中等离子体激元激发和带间跃迁之间的微妙相互作用。能带结构效应，特别是激发类似$d$的能带的能量，决定了亚阈值等离子体激元模式的存在，该模式在Ag中表现为3.8 eV的尖锐共振。然而，在其他贵金属中没有观察到这种共振。在这里，这种不同的行为也进行了分析和解释。
