Optically derived energy band gap states of Pr in ceria

Structural characterization of Tb- and Pr-doped ceria

“…In particular, the band at~400-500 nm, observed also by Guo et al [25], complies with the introduction of discrete acceptor levels into the ceria band gap, with the consequent promotion of electrons from the ceria valence band to the empty Tb +4 /Pr +4 levels [29]. This transition was observed to be inhibited in reduced Pr-doped samples, because of the occupation of the acceptor levels corresponding to the +3 state [29].…”

Chemomechanics of ionically conductive ceramics for electrical energy conversion and storage

“…Because concentrations of cations and compensating defect species (e.g., oxygen vacancies) are coupled via the defect charge neutrality relation, optical absorption measurement allows investigation of the equilibrium properties of defects as well as reaction kinetics. After some studies on oxide single crystals were reported [35,36], more recently some of the present authors have demonstrated that in situ optical absorption measurements can be a powerful means for monitoring oxygen nonstoichiometry and surface exchange kinetics in oxide thin films [37,38]. For example, optical absorption of PCO in the visible spectrum was tied to the fraction of Pr in its oxidized state (4+), which in turn could be related to the oxygen deficiency of the material.…”

Elastoplastic Properties of (Pr, Ce)O2-δ Thin Films

“…Films of Pr x Ce 1-x O 2-δ with compositions of x = 0, 0.10, and 0.20 were grown via pulsed laser deposition on 10 x 5 x 0.5 mm (001) oriented single crystal YSZ (8 mol % Y 2 O 3 stabilized zirconia, MTI Corporation, Richmond, CA), as described in detail previously (22). Dense targets were prepared via sintering the corresponding powders above 1400 °C under N 2 atmosphere.…”

“…(Pr, Ce)O 2-δ (hereafter termed PCO) is a model fluorite-structured non-stoichiometric oxide system that has been widely studied in terms of defect chemistry, transport behavior, and optical properties (3,4,(21)(22)(23)(24). PCO is a mixed ionic-electronic conductor (MIEC) that can exhibit large oxygen vacancy concentration changes under oxidizing conditions (air) at elevated temperatures (T > 500 °C) due to the mixed-valent nature of the Pr dopant.…”