Decoding the evolution of peroxo precursors into perovskite oxides through real space analysis

Oxides with ABO3-type perovskite structures are of great scientific interest due to their diverse technological applications. Here we demonstrate the phase formation pathways and local structural evolution of two distinct perovskite oxides synthesized from hydrogen peroxide-derived peroxo precursors. Utilizing advanced techniques, including electron real space pair distribution function analysis, we monitored their thermal evolution. Our findings reveal that the initial disorder in the B-O octahedron critically influences the crystallization path. Highly distorted B-O octahedra lead to amorphous precursors and a nucleation and growth pathway, whereas minimal distortions result in crystalline precursors undergoing topotactic phase transformation to the ABO3 phase. These pathways culminate in varying disorder levels in the final nanometric materials, providing insights crucial for tailoring material properties for specific applications. ABO₃-type perovskite oxides are scientifically important because of their diverse technological applications. Here, the authors show that initial B–O octahedral disorder determines the crystallization pathways of two perovskite oxides formed from peroxo precursors, leading to either amorphous or crystalline intermediates and distinct disorder in the final nanomaterials.