Optoelectronic excitations and photovoltaic effect in strongly correlated materials

John E. Coulter, Efstratios Manousakis, Adam Gali

Research output: Contribution to journalArticle

18 Citations (Scopus)


Solar cells based on conventional semiconductors have low efficiency in converting solar energy into electricity because the excess energy beyond the gap of an incident solar photon is converted into heat by phonons. Here we show by ab initio methods that the presence of strong Coulomb interactions in strongly correlated insulators (SCIs) causes the highly photoexcited electron-hole pair to decay fast into multiple electron-hole pairs via impact ionization (II). We show that the II rate in the insulating M1 phase of vanadium dioxide (chosen for this study as it is considered a prototypical SCI) is 2 orders of magnitude higher than in Si and much higher than the rate of hot electron-hole decay due to phonons. Our results indicate that a rather broad class of materials may be harnessed for an efficient solar-to-electrical energy conversion that has been not considered before.

Original languageEnglish
Article number165142
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number16
Publication statusPublished - Oct 30 2014

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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