Vacancy-Induced Niobate Perovskite-Tungsten Bronze Composite for Synergetic Tuning of Ferroelectricity and Band Gaps

Niobate perovskites like the (K,Na)NbO3 (KNN) family are among most important lead-free ferroelectrics. Ba and Ni have been co-doped into KNN to induce Ni2+-oxygen vacancy defect dipoles significantly reduce band gap while maintaining ferroelectricity. This opens doors novel optoferroelectric applications such as multisensors photocatalysts. However, obtaining a single phase of above is difficult due sensitive stoichiometry on formation arduous nickel diffusion unit cells during synthesis. paper reports an alternative approach simultaneously tune A-site vacancies intentionally introduced mixtures starting reactants. The homogeneously distributed trigger self-assembly niobate perovskite tungsten bronze thus form composite. interface between two phases, which mimics heterojunction, rather than any individual phase, proven be responsible for resultant narrow strong Hypotheses proposed based results ferroelectric, photoconductivity, density functional theory-based studies explain mechanism. offers additional option engineer polarizations structures in complex photoferroelectric oxides, especially alkaline niobates.