Synthesis of Fine Micro-sized BaZrO₃ Powders Based on a Decaoctahedron Shape by the Microwave-Assisted Hydrothermal Method

Abstract

Micro-sized decaoctahedron BaZrO3 powders were synthesized by means of a hydrothermal microwave method at 140 °C for 40 min. The X-ray diffraction, Raman, UV−visible, and inductively coupled plasma atomic emission (ICP-AES) spectroscopy, as well as measurements of photoluminescence (PL) emission, were used for monitoring the formation of a perovskite phase with random polycrystalline distortion in the structure. Two emissions at 477 and 526 nm were accompanied by increase in the gap values, indicating the existence of different emission mechanisms. A theoretical model derived from previous first principle calculations allow us to discuss the origin of the photoluminescence emission in BaZrO3 powders which can be related to the local disorder in the network of both ZrO6 octahedral and dodecahedral (BaO12) hence forming the constituent polyhedron of BaZrO3 system. Initial observations of a novel morphology of the BaZrO3 perovskite crystal growth based on decaoctahedron shape is demonstrated and indirectly related to photoluminescence emissions.

Cathodoluminescence characterization of polystyrene-BaZrO3 hybrid composites

“…3, curve 1) shows the crystalline structure of BZ powders, it is typical for nanosized BZO powder described in literature [18,19,27]. A small amount of BaCO 3 phase is observed, which can be expected for such samples [18,19,27].…”

“…We believe that this could be caused by the surface-related defects. It is known such near band gap emission in BaZrO 3 strongly depends on the conditions of fabrication and structural quality of samples [16,18,27].…”

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

“…4) which can be associated with the degree of structural order-disorder defects during the reversed crystallization process. 50 Nevertheless, the scintillation associated with RL emission is not as sensitive to these subtle relationships of order-disorder along the crystal growth evolution, and in this case, only defects caught within the band gap of the crystalline compound can effectively participate in the process. 8 To understand the correlation between the luminescence properties and the formation process, we employed the concept of constituent polyhedral clusters as structural motifs.…”

“…59 In oxides, the relative intensity of the A and B peaks depends strongly on the chemical environment around the Zr cations. 59 In the temperature that the spectra were acquired (25 C), a cubic structure is the thermodynamically stable phase for BZO 50 as shown in Fig. 1.…”

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

“…This material is chemically and thermally stable 4,5 , as well as their optical properties were observed under different circumstances, since quasi-amorphous compounds 6 through quasi-crystalline systems 6,7 and finally to periodic crystals 8,9 . BZO presents cubic perovskite sym- metry with ZrO 6 octahedral and BaO 12 cubooctahedral clusters.…”