The structural complexity of perovskites

Area of Science:

• Materials Science
• Solid-State Chemistry
• Crystallography

Background:

• The integration of molecular components into ABX3 perovskite structures represents a novel research avenue.
• This approach has shown promise in developing advanced materials for photovoltaics, ferroelectrics, and barocalorics.
• Substituting atoms with molecules expands the accessible chemical space, enabling the design of materials with tailored properties.

Purpose of the Study:

• To quantify and analyze structural complexity in perovskite materials.
• To establish a correlation between chemical diversity and structural complexity.
• To identify novel distortion schemes in perovskites using a quantitative complexity metric.

Main Methods:

• Application of an information theory-based rating scheme to assess structural complexity.
• Analysis of various perovskite classes, including those with molecular substitutions.
• Correlation of structural complexity with the size of the ReO3-type network and distortion modes.

Main Results:

• Chemical diversity in perovskites is directly linked to increased structural complexity.
• Structural complexity scales with the size of the pseudocubic ReO3-type network.
• The study identified complex octahedral tilts, shifts, and coordination network deformations with unusual propagation vectors.

Conclusions:

• Structural complexity is a valuable metric for understanding and predicting material properties in perovskites.
• The findings support the concept that increased chemical freedom leads to greater structural complexity and potential for novel material properties.
• This framework aids in the rational design of perovskite materials with specific functionalities.