论文标题
变形诱导的电荷重新分布在室温下在室温下薄膜
Deformation-induced charge redistribution in Ceria thin film at room temperature
论文作者
论文摘要
Tuning electronic properties through strain engineering of metal oxides is an important step toward understanding electrochemical and catalytic reactions in energy storage and conversion devices. Traditionally, strain engineering studies focused on movement of oxygen ions at high temperatures (500 °C and above), complicating electrical properties by introducing mixed electronic and ionic conductivity. In this study, we demonstrate room temperature charge redistribution in a CeO2 thin film as a result of phase transformation in a localized region by mechanical deformation. CEO2薄膜在室温下的机械凹痕导致不可逆的变形。导电尖端原子力显微镜（C-AFM）分析显示，通过CEO2薄膜的局部变形区域的电流增加。 Electron energy loss spectroscopy (EELS) analysis equipped with transmission electron microscopy (TEM) suggests that the increase in current contrast in the deformed region arises from an increased concentration of Ce3+ ions. We herein discuss the fundamental reason behind the increased amount of Ce3+ ions in the deformed area, based on the atomic scale computational works performed by molecular dynamics (MD) simulations and first-principles density functional theory (DFT) calculations.塑性变形可诱导立方氟含石CEO2的相变成新形成的T-CEO2结构。 This phase transformation occurs mainly by oxygen ions moving closer to cerium ions to release mechanical energy absorbed in the CeO2 thin film, followed by charge redistribution from the initial CeO2 to the newly created T-CeO2 structure.
Tuning electronic properties through strain engineering of metal oxides is an important step toward understanding electrochemical and catalytic reactions in energy storage and conversion devices. Traditionally, strain engineering studies focused on movement of oxygen ions at high temperatures (500 °C and above), complicating electrical properties by introducing mixed electronic and ionic conductivity. In this study, we demonstrate room temperature charge redistribution in a CeO2 thin film as a result of phase transformation in a localized region by mechanical deformation. Mechanical indentation of the CeO2 thin film at room temperature results in irreversible deformation. Conductive-tip atomic force microscopy (C-AFM) analysis shows increased current passing through the locally deformed area of the CeO2 thin film. Electron energy loss spectroscopy (EELS) analysis equipped with transmission electron microscopy (TEM) suggests that the increase in current contrast in the deformed region arises from an increased concentration of Ce3+ ions. We herein discuss the fundamental reason behind the increased amount of Ce3+ ions in the deformed area, based on the atomic scale computational works performed by molecular dynamics (MD) simulations and first-principles density functional theory (DFT) calculations. Plastic deformation induces a phase transformation of cubic fluorite CeO2 into a newly formed T-CeO2 structure. This phase transformation occurs mainly by oxygen ions moving closer to cerium ions to release mechanical energy absorbed in the CeO2 thin film, followed by charge redistribution from the initial CeO2 to the newly created T-CeO2 structure.
