On the reversed crystal growth of BaZrO3 decaoctahedron: shape evolution and mechanism

Abstract

BaZrO 3 (BZO) nanoparticles were nucleated, grown and subsequently self-assembled into a 3D decaoctahedronal architecture via a microwave-assisted hydrothermal (MAH) method. X-Ray diffraction (XRD), field emission scanning microscopy (FE-SEM), X-ray absorption spectroscopy (XAFS) as well as both photoluminescence (PL) and radioluminescence (RL) emission studies have provided fundamental insight into the nature of the anisotropic crystal growth mechanism of BZO nanocrystals into their final decaoctahedral shape. The growth mechanism of the assembled nanoparticles via mesoscale transformations to form BZO decaoctahedrons occurs from the surface to the core along a reversed crystallization route. This pathway is accompanied by a large enhancement of RL emissions while the intensity of PL emissions is enhanced and worsened along the process. The analysis of the results reveals a relationship between the decaoctahedrons obtained and their optical properties.

Cathodoluminescence characterization of polystyrene-BaZrO3 hybrid composites

“…This spectrum is similar to PL emission profile [16,17] and is typical for multiphonon and multilevel process, i.e., a system in which the electronic relaxation occurs by several paths, including numerous energy levels within the band gap [7]. According to [16][17][18][19][20]26] Figure 2 illustrates CL spectra of nano-BZO samples, both as prepared and annealed during 2 h at different temperatures (up to 800 °C). These results demonstrate hightemperature stability of CL intensity and spectral composition, contrary to the results published earlier [16][17][18][19][20]26].…”

“…According to [16][17][18][19][20]26] Figure 2 illustrates CL spectra of nano-BZO samples, both as prepared and annealed during 2 h at different temperatures (up to 800 °C). These results demonstrate hightemperature stability of CL intensity and spectral composition, contrary to the results published earlier [16][17][18][19][20]26]. This behavior is attributed to micro-BZO (d < 10 μm) powders.…”

“…Since recently it also attracts a considerable attention as a fluorescent material. It is well known that the luminescent characteristics of BZO significantly depend on fabrication technology of micro-and nanocrystals; using different technological routes, samples can be tailored to show violet, blue, green or red luminescence [7,8,[16][17][18][19][20].…”

Fingerprints of short-range and long-range structure in BaZr1−xHfxO3 solid solutions: an experimental and theoretical study

“…We can also observe that the selfassembled process become more evident, probably due to the slight increase of individual nanoparticles. Recently, we have observed a reversed crystal growth process to pure BZO compound as a result of competition between self-assemble and Oswald ripening processes 47 . In this case the introduction of Hf seems to prevent the Oswald repining, due to increased growth of individual grains or/and by homogenization of the grain size distribution, avoiding a great reversed crystallization process as observed to pure BZO 47 .…”

Growth of Colloidal Nano-particles: New Biomaterials

“…The resulting-material (crystals) shows complex structures varying from one dimensional chain up to three dimensions array. So far the final structure diffracts as a single crystal, embodiment that the primary NPs aligned during initial outgrowth [7] and oriented attachments occurs when coalescence is synchronized and accompanied by co-alignment [8]. However, the track by which oriented attachments occurs has not been effectively known.…”