Sol–gel synthesis of oxide perovskites: a framework for precursor chemistry, defect engineering, and structure–property relationships

Abstract

Oxide perovskites are a versatile class of functional materials whose electrical, dielectric, magnetic, and catalytic properties are strongly governed by synthesis pathways and defect chemistry. Among available fabrication methods, sol–gel processing provides distinct advantages, including molecular-level mixing, precise compositional control, and reduced crystallization temperatures. However, despite several recent reviews on perovskite materials and their applications, a unified synthesis–structure–property framework specifically addressing how sol–gel precursor chemistry, gelation mechanisms, defect engineering, and thermal processing collectively govern the structural evolution and functional performance of oxide perovskites remains lacking. In this review, a unified framework for sol–gel synthesis of oxide perovskites is established by classifying processing strategies based on precursor chemistry and gelation mechanisms, including alkoxide-based, citrate/Pechini, and non-alkoxide routes. The relationships between synthesis parameters and key structural features such as cation distribution, lattice distortion, grain size, and phase purity are critically analyzed. Emphasis is placed on oxygen vacancy formation and control, highlighting their central role in tuning electrical and catalytic properties. Furthermore, sol–gel-derived perovskites are systematically compared with materials prepared by conventional solid-state methods to clarify differences in homogeneity, defect distribution, and microstructural control. Functional applications in dielectric devices, catalysis, energy systems, and magnetic materials are discussed within a consistent synthesis–structure–property framework rather than as isolated case studies. Finally, emerging directions in sustainable sol–gel processing, including the use of low-toxicity precursors and energy-efficient routes, are evaluated alongside current challenges related to scalability and reproducibility. This review provides a coherent conceptual basis for understanding and optimizing sol–gel processing in oxide perovskites, offering guidance for the rational design of advanced functional materials.

Graphical Abstract