Effect of Tb³⁺ ions on the ZnO nanoparticles synthesized by chemical bath deposition method

Tb³⁺ doped ZnO nanoparticles were synthesized using the chemical bath deposition (CBD) method at 80 °C. All the samples were annealed at 700 °C to remove the hydroxyl groups confirmed by the thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTGA). The thermal analysis, structure, morphology and optical properties were characterized. The TGA and DTGA showed that the final yield decreases with an increase in the amount of molar concentration of Tb³⁺ ions. The X-ray diffraction (XRD) spectra of the ZnO: Tb³⁺ nanoparticles correspond to the various planes of hexagonal ZnO phase for the lower and higher Tb concentration samples. The estimated average grain sizes calculated using the XRD spectra were found to be in the order of 44 ±2 nm. The grain size was found to increase with an increase in the amount of Tb³⁺ ions. Scanning electron microscopy (SEM) micrographs showed nanoparticles are obtained for undoped ZnO and emergence of pyramids shape for higher molar concentration of Tb³⁺ ions. The reflectance spectra depict a red shift with an increase in Tb³⁺ molar concentration. Photoluminescence (PL) results showed that the luminescence intensity increased with an increase in the amount of Tb³⁺ ions.