Photoexcited metals can produce highly energetic hot carriers whose controlled generation and extraction is a promising avenue for technological applications. While hot-carrier dynamics in Au-group metals have been widely investigated, a microscopic description of the dynamics of photoexcited carriers in the mid-infrared and near-infrared Pt-group metals range is still scarce. Since these materials are widely used in catalysis and, more recently, in plasmonic catalysis, their microscopic carrier dynamics characterization is crucial. We employ ab initio many-body perturbation theory to investigate the hot-carrier generation, relaxation times, and mean free path in bulk Pd and Pt. We show that the direct optical transitions of photoexcited carriers in these metals are mainly generated in the near-infrared range. We also find that the electron-phonon mass enhancement parameter for Pt is 16% higher than Pd, a result that helps explain several experimental results showing diverse trends. Moreover, we predict that Pd (Pt) hot electrons possess total relaxation times of up to 35 fs (24 fs), taking place at approximately 0.5 eV (1.0 eV) above the Fermi energy. Finally, an efficient hot electron generation and extraction can be achieved in nanofilms of Pd (110) and Pd (100) when subject to excitation energies ranging from 0.4 to 1.6 eV.
Bibliographical noteFunding Information:
A.R.R. acknowledges support from ICTP-SAIRF (FAPESP Project No. 2011/11973-4). M.S.L. acknowledges the financial support from the National Science Foundation (Award No. 20-16617). A.M. acknowledges the funding received from the European Union projects: MaX Materials design at the eXascale H2020-EINFRA-2015-1, Grant Agreement No. 676598, and H2020-INFRAEDI-2018-2020/H2020-INFRAEDI-2018-1, Grant Agreement No. 824143; Nanoscience Foundries and Fine Analysis-Europe H2020-INFRAIA-2014-2015, Grant Agreement No. 654360. This work uses the computational resources from GRID-UNESP.
© 2022 American Physical Society.