Ab Initio Simulation of the Absorption Spectra of Photoexcited Carriers in TiO2 Nanoparticles

Francesca Nunzi, Filippo De Angelis, Annabella Selloni

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

We investigate the absorption spectra of photoexcited carriers in a prototypical anatase TiO2 nanoparticle using hybrid time dependent density functional theory calculations in water solution. Our results agree well with experimental transient absorption spectroscopy data and shed light on the character of the transitions. The trapped state is always involved, so that the SOMO/SUMO is the initial/final state for the photoexcited electron/hole absorption. For a trapped electron, final states in the low energy tail of the conduction band correspond to optical transitions in the IR, while final states at higher energy correspond to optical transitions in the visible. For a trapped hole, the absorption band is slightly blue-shifted and narrower in comparison to that of the electron, consistent with its deeper energy level in the band gap. Our calculations also show that electrons in shallow traps exhibit a broad absorption in the IR, resembling the feature attributed to conductive electrons in experimental spectra.

Original languageEnglish (US)
Pages (from-to)3597-3602
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume7
Issue number18
DOIs
StatePublished - Sep 15 2016

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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