清华大学王轲团队报道了用缺陷工程识别非化学计量无铅钙钛矿的界面极化。相关研究成果于2022年12月16日发表于国际一流学术期刊《德国应用化学》。

钙钛矿铁电体的最新进展培育了一系列令人兴奋的传感器和致动器。缺陷工程为铁电材料，尤其是无铅材料的性能提供了关键控制。然而，由于测量技术的复杂性，定量研究缺陷的浓度仍然是一个挑战。

该文中，研究人员提出了一种分析碱金属铌酸盐中A位缺陷和电子的可行方法。基于缺陷化学平衡，可以建立缺陷浓度、电导率和氧分压之间的理论关系。缺陷的类型和浓度通过电导率随氧分压的变化来反映。结果，缺陷浓度的变化导致缺陷驱动的界面极化，这进一步导致陶瓷的不同性质，例如，异常介电行为。此外，该研究还提出了一种优化性能的控制钙钛矿氧化物中缺陷和电荷的策略。

附：英文原文

Title: Identifying the Interfacial Polarization in Non-stoichiometric Lead-Free Perovskites by Defect Engineering

Author: Ze Xu, Yi-Xuan Liu, Maryam Azadeh, Hao-Cheng Thong, Yuqi Jiang, Fang-Zhou Yao, Zhen-Xing Yue, Zhong-Tai Zhang, Zi-Long Tang, Jing-Feng Li, Heng Wang, Till Fr, Ke Wang

Issue&Volume: 2022-12-16

Abstract: Recent advances in perovskite ferroelectrics have fostered a host of exciting sensors and actuators. Defect engineering provides critical control of the performance of ferroelectric materials, especially lead-free ones. However, it remains a challenge to quantitatively study the concentration of defects due to the complexity of measurement techniques. Here, a feasible approach to analyzing the A-site defect and electron in alkali metal niobate is demonstrated. The theoretical relationships among defect concentration, conductivity, and oxygen partial pressure can be established based on the defect chemistry equilibria. The type and concentration of defects are reflected through the conductivity variation with oxygen partial pressure. As a result, the variation of defect concentration gives rise to defect-driven interfacial polarization, which further leads to distinct properties of the ceramics. e.g., abnormal dielectric behavior. Furthermore, this study also suggests a strategy to manipulate defects and charges in perovskite oxides for performance optimization.

DOI: 10.1002/anie.202216776

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202216776