The influence of annealing temperature on the structure and optical properties of Gd2Zr2O7 nanostructures prepared by chemical bath deposition method

Highlights: • Gd₂Zr₂O₇ powders were prepared for the first time using chemical bath deposition method. • XRD the results revealed the presence of the hexagonal ZnO as secondary peaks. • Secondary peaks from hexagonal ZnO have effect on both structure and optical properties. • SEM revealed the cubic and hexagonal crystallites are attributed to both the Gd₂Zr₂O₇ and ZnO, respectively. • PL results revealed that the T_a regulates the defects emission. -- Abstract: Gadolinium zirconate (Gd₂Zr₂O₇) powders were prepared for the first time using chemical bath deposition (CBD) method. In this study, the chemical bath deposition (CBD) method was employed due to its simplicity, cheap, low temperature, versatile and it gives better homogeneity. The effect of annealing temperature (T_a) on the thermal, structural, morphological, and optical properties were investigated. Thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTGA) showed that the material is thermally stable between 400 and 900 °C. The X-ray diffraction (XRD) results confirmed the cubic Gd₂Zr₂O₇ phase with hexagonal ZnO secondary peaks. Scanning electron microscopy (SEM) results revealed the transformation of irregular particles to hexagonal-like structure shape with an increase in T_a. Energy dispersive x-ray spectroscopy (EDS) analysis confirmed the presence of the expected elements. Transmission electron microscopy (TEM) confirmed the nano-nature of the prepared powders. Ultraviolet-visible spectroscopy (UV-Vis) spectra showed a slightly red shift with an increase in T_a. The photoluminescence (PL) results revealed that the emission intensity and peak position in UV region highly depends on the T_a. It was also noted that both secondary peaks from hexagonal ZnO and T_a regulates the defects emission. The international illumination (CIE) color chromaticity showed that the color shifts from blue to yellow-greenish with an increase in T_a. The approach in the present study opened a new way to tune band gap and luminescence intensity of Gd₂Zr₂O₇.