Xiong Xuhui, Liu Zhengwang, Zhang Ruixuan, Yang Liting, Liang Guisheng, Zhou Xiaodi, Li Bangxin, Zhang Huibin, Lv Hualiang, Che Renchao
Laboratory of Advanced Materials, Shanghai Key Lab of Molecular Catalysis and Innovative Materials, Academy for Engineering & Technology, Advanced Coatings Research Center of Ministry of Education of China, Fudan University, Shanghai, 200438, China.
Institute of Optoelectronics, Fudan University, Shanghai, 200433, China.
Adv Mater. 2025 Jan;37(4):e2415351. doi: 10.1002/adma.202415351. Epub 2024 Nov 28.
Dielectric oxides with robust relaxation responses are fundamental for electronic devices utilized in energy absorption, conversion, and storage. However, the structural origins governing the dielectric response remain elusive due to the involvement of atomically complex compositional and structural environments. Herein, configurational entropy is introduced as a regulatory factor to precisely control the structural heterogeneity in representative perovskite dielectric oxides. Through advanced structural and electric field visualization studies, a novel quantitative relationship is established between atomic-level structural disorder-induced electric field polarization and macroscopic dielectric properties. The results indicate that the degree of atomic delocalization in perovskite oxides exhibits a near-parabolic trend with increasing entropy, reaching a maximum in medium-entropy perovskite. Correspondingly, the atomic electric field vectors display significant asymmetrical distribution, thus greatly enhancing angstrom-scale electric field polarization. Then, it is experimentally proven that entropy-driven electric polarization can improve the dielectric relaxation behavior characterized by broader frequency and stronger intensity of electromagnetic energy absorption, with improvements of approximately 160% and 413% compared to structurally homogeneous control. This study unveils the quantitative correlation between angstrom-scale electric field polarization and dielectric response in perovskite oxides, offering a novel perspective for exploring the structure-property relationship in dielectric materials.
具有强大弛豫响应的介电氧化物对于用于能量吸收、转换和存储的电子设备至关重要。然而，由于涉及原子级复杂的成分和结构环境，控制介电响应的结构起源仍然难以捉摸。在此，引入构型熵作为调节因子，以精确控制代表性钙钛矿介电氧化物中的结构异质性。通过先进的结构和电场可视化研究，在原子级结构无序诱导的电场极化与宏观介电性能之间建立了一种新的定量关系。结果表明，钙钛矿氧化物中的原子离域程度随着熵的增加呈现近抛物线趋势，在中熵钙钛矿中达到最大值。相应地，原子电场矢量显示出明显的不对称分布，从而极大地增强了埃级电场极化。然后，实验证明熵驱动的电极化可以改善以更宽频率和更强电磁能量吸收强度为特征的介电弛豫行为，与结构均匀的对照相比，改善幅度约为160%和413%。本研究揭示了钙钛矿氧化物中埃级电场极化与介电响应之间的定量相关性，为探索介电材料的结构-性能关系提供了新的视角。
