Size-controlled growth of spherical nanoparticles of Y-doped BaZrO3 perovskite

Abstract

Yttrium-doped BaZrO 3 (BZY) was processed by a simple yet effective chemical synthesis route that yielded perfectly spherical particles. The particle size was found to decrease with increasing molar concentration of cations in the solution. Thus, the process offered a great ease of controlling the particle size as well. The close control over morphology and size can provide an opportunity of tuning the properties of such particles. The average particle size as obtained from high-resolution scanning electron microscopy (HR-SEM) was 243, 206, 149, and 79 nm at 0.2, 0.5, 0.8, and 1 M concentration, respectively. At a processing temperature of 60°C, the undesirable phases, BaCO 3 and Zr 1-x Y x O 2 , were present along with BZY even after calcination at 600°C, and it took a very long processing time (160 min) for complete phase formation. The BZY phase formed within 45 min at a reaction temperature of 90°C and yielded phase pure powders on calcination at the same temperature (600°C). The d-spacing (2.98 Å ) obtained from the lattice fringes in high-resolution transmission electron microscopy (HR-TEM) confirmed the cubic perovskite phase of BaZrO 3 . The average crystallite size calculated from XRD analysis coupled with the TEM observations revealed that each spherical particle consists of only few crystallites.

Composite electrolyte used for low temperature SOFCs to work at 390°C

“…More importantly, the interface regions between YSZ and BZY particles are numerous and tightly related to the two-phase materials over the overlapping region, which can offer ion conduction pathways to improve ion conductivity. 39 A normal charge transfer route for oxygen ion conduction is also established during the YSZ phase, which is crucial for cell performance.

Figure 5 TEM and HR-TEM images of the tested YSZ-BZY electrolyte (A–H) Low-resolution TEM image (A, F), TEM-EDS mapping images (B–E) and HR-TEM images (G, H) of the tested YSZ-BZY electrolyte.

…”

Current–voltage characteristics and photovoltaic effect of a Au/ZnFe2O4/GaN Schottky junction

“…Gallium nitride (GaN) has attracted huge research interest due to its potential application in high-frequency, high-power, and optoelectronic devices [1,2]. Its distinctive properties such as wide band gap (∼3.4 eV), high breakdown field strength, and good thermal conductivity have allowed it to be exploited in the development of ultraviolet (UV) photodetectors, lightemitting diodes, metal-oxide-semiconductor field-effect transistors and capacitors, and high-electron-mobility transistors [3][4][5][6][7][8][9]. Metal-semiconductor (MS) Schottky junctions based on GaN have frequently displayed an anomalous leakage current under reverse bias voltages and a low breakdown voltage, resulting in poor device performance, poor thermal stability, and degradation of diode behavior [10][11][12].…”