Plasmon-induced hot-carrier generation differences in gold and silver nanoclusters

Abstract

In the last thirty years, the study of plasmonic properties of noble metal nanostructures has become a very dynamic research area. The design and manipulation of matter in the nanometric scale demand a deep understanding of the underlying physico-chemical processes that operate in this size regimen. Here, a fully atomistic study of the spectroscopic and photodynamic properties of different icosahedral silver and gold nanoclusters have been carried out by using Time-Dependent Density Functional Tight-Binding (TD-DFTB) model. Optical absorption spectra of different icosahedral silver and gold nanoclusters of diameters between 1 and 4 nanometers has been simulated. Furthermore, the energy absorption process have been quantified by means of calculating a fully quantum absorption cross-section using the information contained in the reduced single-electron density matrix. This approach allows us take into account for the quantum confinement effects dominating in this size regime. Likewise, the plasmon-induced hot-carrier generation process under laser illuminations have been explored from a fully dynamical perspective. We have found noticeable differences in the energy absorption mechanisms and the plasmon-induced hot-carrier generation process in both metals which can be explained by their respective electronic structures.These difference can be attributed to the existence of ultra-fast electronic dissipation channels in gold nanoclusters that are absented in silver nanoclusters. To the best of our knowledge, this is the first report that addresses this topic from a real time fully atomistic time-dependent approach.

Dissipative Equation of Motion for Electromagnetic Radiation in Quantum Dynamics

“…Introduction.-Time-dependent electronic structure simulations are currently applied to fundamental phenomena at the nanoscale, from spectroscopy [1][2][3][4] and photochemistry [5][6][7][8] to quantum conductance [9][10][11][12][13] and energy transfer in molecules and materials [2,[14][15][16][17]. Despite the insight that these simulations provide, they lack an important ingredient: the radiative energy dissipation for any charge density evolving in time.…”

Plasmonic Metasensors Based on 2D Hybrid Atomically Thin Perovskite Nanomaterials

“…Single layer hBN is also known as white graphene. It has been well demonstrated that the silver substrate could provide a much narrower width of the resonance curves and also deeper resonance dips [49,50]. Two-dimensional perovskite is sandwiched between the hBN and graphene layers, where its optical property will not be affected due to oxidization and liquid contaminations [51,52].…”

Plasmonic enhancement of molecular hydrogen dissociation on metallic magnesium nanoclusters

“…A similar analysis has been conducted for noble metals in other recent reports. 5,11,15 The population and depopulation dynamics of ground state molecular orbitals (MO) are distinguished with positive and negative population values, indicating hot electron and hot hole generation, respectively. These MO population differences are calculated with respect to the ground-state population at the initial time t = 0 (∆ρ ii =ρ ii (t) − ρ ii (0)).…”

“…The absorption cross-section associated with these plasmonic materials is often several orders of magnitude larger than most organic dye molecules. [1][2][3]5 Plasmonic nanomaterials have rapidly found different applications in several fields such as optical-sensors, 6 enhanced spectroscopies, 7 and even biomedical application. 8 Recently, it has been reported that some plasmonic materials are able to effectively produce highly energetic distributions of electron-hole-pair (EHP) excitations upon non-radiative decay associated with dephasing of the plasmonic excitation (Landau damping).…”

“…8 Recently, it has been reported that some plasmonic materials are able to effectively produce highly energetic distributions of electron-hole-pair (EHP) excitations upon non-radiative decay associated with dephasing of the plasmonic excitation (Landau damping). 5,[9][10][11][12][13][14] EHPs act as hot-carriers and can potentially promote bond formation/dissociation events in molecules adsorbed on or nearby the plasmonic material. This is often discussed in terms of two possible mechanisms.…”