Experimental and theoretical study on the structural, electronic, and optical properties within DFT+U, Fxc kernel for LRC model, and BSE approaches. Part I: CoTiO3 and Co2TiO4 pigments

Abstract

Prediction of the ceramic pigment's color using theoretical calculations is a new and significant topic. In this work, the CoTiO3 and Co2TiO4 pigments were synthesized. We modeled these structures and performed calculations within the DFT+U approach. We studied the structural, electronic, optical, and colorimetric properties of the structures. We used many-body Fxc kernel for long-range correction (LRC) model and Bethe–Salpeter equation (BSE) methods to predict the absorption spectra and color of the CoTiO3 and Co2TiO4 structures. The structures were characterized by FE-SEM, XRD, Raman spectroscopy, UV–Vis spectroscopy, and CIE L∗a∗b∗ colorimetry methods. The electronic property calculations indicated that the energy gap calculated for CoTiO3 and Co2TiO4 samples is approximately 2.5 and 1.1 eV, respectively, which are close to the experimentally measured ones. The calculated optical and colorimetric properties showed that the results are close to experimental results.