Charge Separation in BaTiO3 Nanocrystals: Spontaneous Polarization versus Point Defect Chemistry

Ellie Neige, Thomas Schwab, Maurizio Ermanno Musso, Thomas Berger, Gilles Bourret, Oliver Diwald (Corresponding author)

Research output: Contribution to journalArticlepeer-review

Abstract

The fate of photogenerated charges within ferroelectric metal oxides is key for photocatalytic applications. The authors study the contributions of i) tetragonal distortion, responsible for spontaneous polarization, and ii) point defects, on charge separation and recombination within BaTiO 3 (BTO) nanocrystals of cubic and tetragonal structure. Electron paramagnetic resonance (EPR) in combination with O 2 photoadsorption experiments show that BTO nanocrystals annealed at 600 °C have a charge separation yield enhanced by a factor > 10 compared to TiO 2 anatase nanocrystals of similar geometries. This demonstrates for the first time the beneficial effect of the BTO perovskite nanocrystal lattice on charge separation. Strikingly, charge separation is considerably hindered within BTO nanoparticles annealed ≥ 600 °C, due to the formation of Ba–O divacancies that act as charge recombination centers. The opposing interplay between tetragonal distortion and annealing-induced defect formation inside the lattice highlights the importance of defect engineering within perovskite nanoparticles.

Original languageEnglish
Article number2206805
Pages (from-to)e2206805
Number of pages7
JournalSmall
Volume19
Issue number16
Early online date22 Jan 2023
DOIs
Publication statusPublished - 22 Jan 2023

Bibliographical note

Publisher Copyright:
© 2023 The Authors. Small published by Wiley-VCH GmbH.

Keywords

  • barium titanate nanoparticles
  • charge carrier recombination
  • defect engineering
  • ferroelectricity
  • spontaneous polarization

Fields of Science and Technology Classification 2012

  • 103 Physics, Astronomy
  • 104 Chemistry

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