Solution-based growth of monodisperse cube-like BaTiO₃ colloidal nanocrystals

The controlled synthesis of free-standing, cubelike BaTiO₃ nanocrystals by a soft solution chemical process was reported. The resulting nanocrystals retain oleic acid molecules on their surfaces and can be easily dispersed in nonpolar solvents. The atmosphere used during the preparation of the solutions before their transfer to the autoclave was found to influence the morphology of the BaTiO₃ nanocrystals. TEM and SEM images show that the BaTiO₃ nanoparticles are well-separated and have the tendency to self-organize into ordered domains on planar surfaces. The XRD pattern of the cubic BaTiO₃ nanoparticles exhibits a series of well-defined peaks that can be indexed into a pseudocubic lattice, suggesting that the sample is single-phase and highly crystalline. The SAED image of the nanocubes exhibits a series of concentric rings with a spotted appearance which can be ascribed to either cubic or the tetragonal BaTiO₃.