Hot Carrier Dynamics at Ligated Silicon(111) Surfaces: A Computational Study

Yulun Han, Kweeni Iduoku, Gena Grant, Bakhtiyor Rasulev, Alexey Leontyev, Erik K. Hobbie, Sergei Tretiak, Svetlana V. Kilina, Dmitri S. Kilin

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

We provide a case-study for thermal grafting of benzenediazonium bromide onto a hydrogenated Si(111) surface using ab initio molecular dynamics (AIMD) calculations. A sequence of reaction steps is identified in the AIMD trajectory, including the loss of N2 from the diazonium salt, proton transfer from the surface to the bromide ion that eliminates HBr, and deposition of the phenyl group onto the surface. We next assess the influence of the phenyl groups on photophysics of hydrogen-terminated Si(111) slabs. The nonadiabatic couplings necessary for a description of the excited-state dynamics are calculated by combining ab initio electronic structures and reduced density matrix formalism with Redfield theory. The phenyl-terminated slab shows reduced nonradiative relaxation and recombination rates of hot charge carriers in comparison with the hydrogen-terminated slab. Altogether, our results provide atomistic insights revealing that (i) the diazonium salt thermally decomposes at the surface allowing the formation of covalently bonded phenyl group, and (ii) the coverage of phenyl groups on the surface slows down charge carrier cooling driven by electron-phonon interactions, which increases photoluminescence efficiency at the near-infrared spectral region.

Original languageEnglish
Pages (from-to)7504-7511
Number of pages8
JournalJournal of Physical Chemistry Letters
Volume12
Issue number31
DOIs
Publication statusPublished - 12 Aug 2021
Externally publishedYes

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