Electronic structure of proton conducting BaCe 0.90Y 0.10O 3− δ

Abstract

The electronic structure of the protonic conductor Y-doped BaCeO 3 (BaCe 0.90Y 0.10O 3− δ ) has been studied by soft-X-ray spectroscopy. The valence band of H 2-annealed BaCe 0.90Y 0.10O 3− δ , which consists of the O 2 p states hybridized with Ce 4 f states, shifts to the higher binding energy side by approximately 0.4 eV. In the air-annealed BaCe 0.90Y 0.10O 3− δ , holes and acceptor levels are observed at the top of the valence band and just above E F, respectively. Their intensities are lower in H 2-annealed BaCe 0.90Y 0.10O 3− δ . These findings indicate directly that hydrogen doping compensates for the presence of the holes.