Charge Separation in BaTiO 3 Nanocrystals: Spontaneous Polarization Versus Point Defect Chemistry.

Autor: Neige E; Department of Chemistry and Physics of Materials, Paris-Lodron Universität Salzburg, Jakob-Haringerstrasse 2a, Salzburg, 5020, Austria., Schwab T; Department of Chemistry and Physics of Materials, Paris-Lodron Universität Salzburg, Jakob-Haringerstrasse 2a, Salzburg, 5020, Austria., Musso M; Department of Chemistry and Physics of Materials, Paris-Lodron Universität Salzburg, Jakob-Haringerstrasse 2a, Salzburg, 5020, Austria., Berger T; Department of Chemistry and Physics of Materials, Paris-Lodron Universität Salzburg, Jakob-Haringerstrasse 2a, Salzburg, 5020, Austria., Bourret GR; Department of Chemistry and Physics of Materials, Paris-Lodron Universität Salzburg, Jakob-Haringerstrasse 2a, Salzburg, 5020, Austria., Diwald O; Department of Chemistry and Physics of Materials, Paris-Lodron Universität Salzburg, Jakob-Haringerstrasse 2a, Salzburg, 5020, Austria.
Jazyk: angličtina
Zdroj: Small (Weinheim an der Bergstrasse, Germany) [Small] 2023 Apr; Vol. 19 (16), pp. e2206805. Date of Electronic Publication: 2023 Jan 22.
DOI: 10.1002/smll.202206805
Abstrakt: 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.
(© 2023 The Authors. Small published by Wiley-VCH GmbH.)
Databáze: MEDLINE
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