Transitional evolution of Strontium Titanate and its intermediaries founded on alkalinity

The manipulation by alkalinity of the morphology, intermediates, defect sites and the crystallinity of the perovskite SrTiO3 (STO) has been studied in this report, through the employment of the least number of reagents. The highest alkaline conditions resulted in the expected phase formation. The nanocrystals synthesized here were processed in aqueous media with Sr(NO3)2 as the Sr2+ and TiCl4 as the Ti4+ sources, in the presence of differing degrees of NaOH to obtain the required alkalinities. The crystallization rate, crystallite size and micro-strain were among the few aspects which varied considerably with solution pH, with the other notable observations being the strain, probably as a result of the incorporation of rutile TiO2 (at lower pH) into the STO lattice with increasing pH. The different nucleation and growth mechanisms that lead to the observed structures and compositions are predicted and confirmed with pertinent characterization tools. The surface reaction, monomer's diffusion to the surface, and size distribution during growth also contribute to the different morphologies, influenced ultimately by the pH. The nature of intermediates thus are interesting to achieve materials that can have tailored compositions, of benefit in applications involving interfacial engineering for example, among other applications.