Influence of rare earth (RE=Nd, Y, Pr and Er) doping on the microstructural and optical properties of ceria nanostructures

Nanopowders of Ce0.9RE0.1O1.95 (RE=Nd, Y, Pr and Er) were synthesized by nitrate-fuel combustion method and calcinated at 700 °C for 2 h to obtain completely crystalline structures. The effect of RE dopants on the crystalline nature, lattice parameters, and microstructural parameters such as microstrain, stress, and deformation energy density of ceria was evaluated through uniform deformation model (UDM), uniform deformation stress model (UDSM) and uniform deformation energy density model (UDEDM) by using the X-ray diffraction (XRD) data. The results revealed that the microstructural parameters were considerably altered with respect to the dopants. The transmission electron microscope (TEM) graphs and their corresponding selected area diffraction (SAED) patterns of ceria nanoparticles confirmed that all doped ceria powders are crystalline with the wide range of particle size distributions aligned in all the directions. The optical diffuse reflectance spectroscopy (DRS) measurements showed a band at around 340 nm attributed to the transitions of charge-transfer between O 2p and Ce 4f orbitals in cerium oxide and RE doped CeO2 exhibited the reflectance band in the visible regions due to the transition of 4f energy levels of RE ions. Photoluminescence (PL) spectra of RE doped ceria showed the blue-green emission bands.