Ferroelectric Oxides with Strong Visible-Light Absorption from Charge Ordering

Author(s)

Jiangang He, Cesare Franchini, James M. Rondinelli

Abstract

The applications of transition metal oxides as photovoltaic and

photocatalytic materials are mainly impeded by their poor visible light

absorption, low photogenerated carrier mobility, and low valence band

position, which originate from the generally large band gap (≥3 eV),

narrow transition metal d states, and deep oxygen 2p

states. Here, we conceive a design strategy to realize small band gap

polar oxides with high carrier mobilities by combining small radii A cations with Bi³⁺/Bi⁵⁺

charge disproportion. We show that these cation sizes and chemical

features shift the valence band edge to higher energies and therefore

reduce the band gap, promoting the formation of highly dispersive Bi 6s

states near the Fermi level as a byproduct. By means of advanced

many-electron-based first-principles calculations, we predict a new

family of thermodynamically stable/metastable polar oxides ABiO₃ (A = Ca, Cd, Zn, and Mg), which adopt the Ni₃TeO₆-type (space group R3)

structure and exhibit optical band gaps of ∼2.0 eV, as promising single

phase photovoltaic and photocatalytic materials operating in the

visible light spectrum.

Organisation(s)

Computational Materials Physics

External organisation(s)

Northwestern University, Argonne National Laboratory

Journal

Chemistry of Materials

Volume

Pages

2445–2451

No. of pages

ISSN

0897-4756

DOI

https://doi.org/10.1021/acs.chemmater.6b03486

Publication date

10-2016

Peer reviewed

Yes

Austrian Fields of Science 2012

103025 Quantum mechanics, 103036 Theoretical physics, 103015 Condensed matter, 103009 Solid state physics

Keywords

ASJC Scopus subject areas

Materials Chemistry, Chemical Engineering(all), Chemistry(all)

Sustainable Development Goals

SDG 7 - Affordable and Clean Energy

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