Authors: Menghui Wang | Huashuai Hu | Shijian Lin | Pan Yang | Dongyan Yang
Source: Chinese Science Bulletin (Chinese Version) (article, 2023-07-01)
Field: Materials Science — Materials Chemistry

Prediction of perovskite structures and thermodynamic stabilities from structural factors <p indent="0mm">Perovskite materials are regarded as “omnipotent materials” due to their excellent physical and chemical properties, and thus have shown varied potential applications, including electrocatalysis, superconductivity, photoelectric conversion, and solidification of high-level nuclear wastes. The stability of perovskites has an important influence on their service performance. In general, the properties of materials are closely related to their structures. Based on the body-centered cubic crystal structure of perovskites, researchers have proposed several structural factors to describe the local or overall structural characteristics of unit cells of perovskite materials, including Goldschmidt’s tolerance factor (<italic>t</italic>), octahedral factor (<italic>μ</italic>), atomic packing fraction (<italic>η</italic>), and new tolerance factor (<italic>τ</italic>). These structural factors can predict the structure and stability of perovskite materials accurately and then guide the design and synthesis of new perovskite materials. The Goldschmidt’s tolerance factor is proposed based on the geometric position relationship between the constituent atoms inside perovskites, which has been widely accepted and applied. Considering the influence of BX<sub>6</sub> octahedral to the structural stability of perovskites, the octahedral factor is proposed. Furthermore, the compactness of each constituent atom accounts for the volume of perovskite unit cells is considered, and then the atomic packing fraction is proposed. The new tolerance factor is proposed because of the influence of elemental valence on the structural stability of perovskites. With the proposal of these four structural factors, the accuracy of structural factors in predicting the structural stability of perovskite has improved, up to more than 90%. Besides, The combinations of these structural factors, such as two-dimensional <italic>t</italic>-<italic>μ</italic> plots, (<italic>μ</italic>+<italic>t</italic>), and (<italic>μ</italic>+<italic>t</italic>)<sup><italic>η</italic></sup>, are also proposed to predict the stability of perovskites. Through first-principles calculations, the correlation between the thermodynamic stability of perovskite materials and structural factors is discovered based on the decomposition energy, which provides a basis for studying the relationship between radiation resistance of perovskite materials and structural factors. In this review, the background, expression, physical significance, and corresponding prediction criteria of these structural factors are introduced in detail, which is expected to provide guidance in the design, synthesis, and application of perovskite materials. In addition, the correlation between structural factors and some properties of perovskites, such as thermal properties, electrical properties, humidity stability, light stability, and radiation resistance stability, is also discussed. Structural factors determine the intrinsic stability of perovskites. The higher the intrinsic stability, the higher the humidity stability and light stability of the perovskite material. Of course, the humidity stability and light stability of the perovskite material are also affected by other factors, such as the preparation process and raw materials. In addition, there exists strongly correlations between structural factors and radiation resistance of ABO<sub>3</sub> perovskites. Therefore, the radiation resistance of ABO<sub>3</sub> perovskites can be predicted through structural factors, which provides a new way to evaluate the material’s radiation resistance. The shortcomings of the current development of structural factors are summarized, and follow-up research directions are also pointed out. Perovskite (structure) ; Thermodynamics ; Materials science ; Chemistry ; Crystallography ; Physics Nuclear materials and radiation effects ; Electronic and Structural Properties of Oxides ; Advancements in Solid Oxide Fuel Cells