Hydrothermal Synthesis of SrTiO3 Mesocrystals: Single Crystal to Mesocrystal Transformation Induced by Topochemical Reactions

• Published in: Crystal growth & design 2012-09, Vol.12 (9), p.4450-4456
• Main Authors: Kalyani, Vishwanath, Vasile, Bogdan S, Ianculescu, Adelina, Buscaglia, Maria Teresa, Buscaglia, Vincenzo, Nanni, Paolo
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Materials science; Nanoscale materials and structures: fabrication and characterization; Other topics in nanoscale materials and structures; Physics; Solid-solid transitions; Specific phase transitions
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/cg300614f

The mechanisms driving the mutual crystallographic alignment of nanocrystals in mesocrystals are various and not yet fully understood. As discussed in this paper, formation of mesocrystals can result from a topochemical reaction between single crystal particles or templates suspended in a liquid phase and ionic/molecular species in solution. In such a case, the initial particle morphology is retained in the final mesocrystal. If the transformation is not topotactic, the final product will maintain no memory of the precursor morphology. The magnitude of the lattice mismatch as well as the defective state of the precursor surface probably determine the degree of mutual crystallographic alignment of the nanocrystals which nucleate and grow on the substrate. Although identified by studying the hydrothermal crystallization of SrTiO3 from different single crystal titania precursors, this mechanism is very general and applicable to a variety of compounds and experimental situations, including solvothermal and molten salt syntheses.