Étude des propriétés structurales, électroniques et optiques des composés Ti 1-x A x O 2 (A= Co, Ce et x=0, 0.125), et du composé Ti 1-2x A x B x O 2(A= Co, B=Ce et x =0.125).

Abstract

Titanium dioxide (TiO2) is an oxide semiconductor. It exists in several forms of which three main ones are rutile, anatase and brookite. Titanium dioxide has very good semiconducting properties, which has attracted the attention of many researchers to study various applications such as photovoltaic devices, electrochromic systems, and photocatalysis ... etc. The objective of this work was to study structural, electronic and optical properties of rutile TiO2 to evaluate the effect of (Ce, Co) doping with a concentration of 12.5%. This study is based on the FP-LAPW method implemented in the Wien2k code and in the framework of the density functional theory (DFT). The generalized gradient approximation (GGA) and the Becke-Johnson approach modified by Tran-Blaha (TB-mBJ) were used to deal the exchange and correlation potential. The results obtained from the study of the structural properties of pure TiO2, Ti0.875Co0.125O2, Ti0.875Ce0.125O2 and Ti0.75Co0.125 Ce0.125O2 compounds are in good agreement with the available data. The study of the electronic and optical properties showed that doping and co-doping modify the gap value of TiO2. The optical spectra of TiO2 doped with cobalt showed a photoresponse in the infrared but the (Co-Ce) co-doping of TiO2 has a higher photoresponse for visible light than that of TiO2 doped only with cobalt or cerium.