Vacuum-level-referenced band tuning induced by ion exchange and exfoliation in layered perovskite KCa2Nb3O10
Abstract
Ion exchange and exfoliation are widely used chemical processes for layered perovskites; however, their impact on vacuum-level-referenced electronic band alignment remains unclear. In this study, we investigate the crystal and electronic band structures of the Dion–Jacobson-type layered perovskite KCa2Nb3O10, its protonated form HCa2Nb3O10, and exfoliated Ca2Nb3O10 nanosheets. Synchrotron x-ray powder diffraction reveals that KCa2Nb3O10 crystallizes in the monoclinic space group P21/m, whereas HCa2Nb3O10 adopts a tetragonal structure with space group P42212, indicating enhanced structural symmetry upon protonation. Energy diagrams referenced to the vacuum level are experimentally determined for all three compounds, enabling direct comparison of valence-band positions and in-gap states induced by ion exchange and exfoliation. In HCa2Nb3O10, a hydrogen-bonded network is found to play a key role in controlling the formation and energy level of in-gap states. These results demonstrate that chemical processing provides an effective route for vacuum-level-referenced band tuning in layered perovskites, offering a practical guideline for band engineering in photocatalytic and related functional oxide materials.
Article Details
Journal Info
Journal of Applied Physics
American Institute of Physics
Authors (15)
Zihao Zhang
Shanghai Engineering Research Center of Tooth Restoration and Regeneration and Tongji Research Institute of Stomatology and Department of Implantology, Shanghai Tongji Stomatological Hospital and Dental School, Tongji University
Norihiro Oshime
Synchrotron Radiation Research Center, Kansai Institute for Photon Science, National Institutes for Quantum Science and Technology (QST), SPring-8, 1-1-1, Sayo-cho, Hyogo 679-5148, Japan
Yosuke Hamasaki
Department of Applied Physics, National Defense Academy 3 , Yokosuka 239-8686,
Minoru Osada
Institute of Materials and Systems for Sustainability (IMaSS)
Shu Morita
Institute of Materials and Systems for Sustainability (IMaSS), Nagoya University 5 , Nagoya 464-8601,
Yutaka Takaguchi
Department of Material Design and Engineering, Faculty of Sustainable Design, University of Toyama 6 , Toyama 930-8555,
Masahiro Yamagami
Faculty of Environmental, Life, Natural Science and Technology, Okayama University 1 , Okayama 700-8530,
Tomoko Okubo
Faculty of Environmental, Life, Natural Science and Technology, Okayama University 1 , Okayama 700-8530,
Kazumasa Horigane
Faculty of Environmental, Life, Natural Science and Technology, Okayama University 1 , Okayama 700-8530,
Naoshi Ikeda
Faculty of Environmental, Life, Natural Science and Technology, Okayama University 1 , Okayama 700-8530,
Tatsuo Fujii
Faculty of Environmental, Life, Natural Science and Technology, Okayama University 1 , Okayama 700-8530,
Pascale Gemeiner
Laboratoire Structures, Propriétés et Modélisation des Solides, CentraleSupélec, CNRS-UMR8580, Université Paris-Saclay 1 , Gif-sur-Yvette 91191,
Pierre-Eymeric Janolin
Satoshi Hirose
Innovative Research Excellence, Honda R&D Co., Ltd 8 , 4630 Shimotakanezawa, Haga-machi, Haga-gun, Tochigi 321-3393,
Jun Kano
Faculty of Environmental, Life, Natural Science and Technology, Okayama University 1 , Okayama 700-8530,