Charge transfer in Pr-Doped cerium oxide: Experimental and theoretical investigations

Abstract

In this study was synthesized cerium oxide (CeO2) doped with praseodymium (Pr) using a microwave-assisted hydrothermal method. The positions of the vacancies with respect to Ce3+/Ce4+ and the vacancy-like defects surrounded by the electronic density of Pr atoms were determined through photoluminescence (PL) measurements, positron annihilation lifetime spectroscopy, and density functional theory (DFT). Distinct PL responses were observed for Pr-doped CeO2 indicating that oxygen vacancies contribute to the formation of deep energy levels in the forbidden region, thus facilitating charge transfer. The interplay between the experimental measurements and computational simulations at the microscopic level based on DFT revealed the charge rearrangement in oxygen-deficient CeO2:Pr systems. These results indicate that oxygen vacancies and electrons at the 4f states contribute to electrical conduction, thereby demonstrating that Pr-doped CeO2 acts as an n-type semiconductor.