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

CRISTINA DE OLIVEIRA, REGIANE; CABRAL, LUIS; CABRAL, ANA CRISTINA; ALMEIDA, PRISCILA BARROS; TIBALDI, NICOLAS; SAMBRANO, JULIO RICARDO; SIMÕES, ALEXANDRE ZIRPOLI; MACCHI, CARLOS EUGENIO; MOURA, FRANCISCO; MARQUES, GILMAR EUGENIO; PONCE, MIGUEL ADOLFO; LONGO, ELSON

MATERIALS CHEMISTRY AND PHYSICS

ELSEVIER SCIENCE SA

Año: 2020 vol. 249

0254-0584

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 Ce3þ/Ce4þand the vacancy-like defects surrounded by the electronic density of Pr atoms were determined through photoluminescence (PL) measure-ments, 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 mea-surements and computational simulations at the microscopic level based on DFT revealed the charge rear-rangement 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