Time resolved in-situ X-ray absorption spectroscopy: new perspectives in the study of semiconductors with promising physico-chemical properties

MARTÍN E. SALETA; SANTIAGO J. A. FIGUEROA; DINA TOBIA; RODOLFO D. SÁNCHEZ

Campinas

Conferencia; 30th Annual Users Meeting of the Brazilian Synchrotron Light Laboratory; 2020

Center for Research in Energy and Materials (CNPEM)

XANES studies, performed at XAFS2 beamline, reveal that the Cr(2-x)TixO3 (x=0.2 - CTO) particles present Ti ions in the +3 & +4 oxidation state. Even more, XPS shown that the Ti ions located at thesurface of the CTO are in the +4 state. The conductivity (σ) of CTO is modeled by small polarons hopping (SPH). σ-curve presents a change in the activation energy associated with a variation in theconduction mechanism (750-790 K). This change is not observed in the magnetic and structural characterization. The intensity of selected peaks of the Ti K-edge XANES spectra as a function oftemperature exhibits a break as occurred in the σ-curve. This change is associated with variations in the electron-phonon interaction. The Ti ions in the particles lead to SPH between the transition metal sites.