Chemistry of defect induced photoluminescence in chalcopyrites: The case of CuAlS2

Abstract

Hybrid exchange density functional theory is used to study the wide band gap chalcopyrite CuAlS 2 . The formation energies of charged and neutral intrinsic defects are calculated for different environmental conditions, and it is shown that CuAlS 2 is a p-type material that cannot be type inverted through the formation of intrinsic defects. The calculated band gap states associated with the different intrinsic defects are used to comment on the origin of the observed CuAlS 2 photoluminescence emissions. The origin and stability of ordered defect compounds derived from CuAlS 2 are investigated, and it is concluded that CuAl 5 S 8 is a stable ordered defect compound, albeit in a small region of phase space.

Thermodynamic stability of LaMnO3and its competing oxides: A hybrid density functional study of an alkaline fuel cell catalyst

“…This is well justified for solids in the temperature and pressure range of interest, because the entropic contribution is mainly vibrational and the volume of solids is nearly independent of pressure and temperature. Hence, these terms are small and tend to cancel [33]. The reference state for oxygen, however, is the gaseous dimer and needs further consideration.…”

“…, can be equated to the ground state energy, as discussed earlier [33]. In the case of the manganese oxides the same approach can be applied; however, since there are several oxides, slightly different manganese chemical potentials arise.…”

Surface morphology ofCuFeS2: The stability of the polar(112)/(112¯)surface pa

“…Electronic exchange and correlation was approximated using the hybrid-exchange B3YLP functional [30,31], chosen because it has shown to reliably describe the geometry, energetics, and electronic properties of bulk CuFeS 2 [13] and a wide range of other strongly correlated systems [32][33][34][35][36][37][38][39]. In particular, the B3LYP functional better predicts the band gaps of semiconductors than functionals based on the local density or generalized gradient approximations [40][41][42].…”

Water adsorption on rutile TiO2(110) for applications in solar hydrogen production: A systematic hybrid-exchange density functional study

“…In order to study the behavior of water on this surface ( 1 ML), we have used hybrid-exchange DFT calculations with the B3LYP functional, which result in an accurate description of the energetics and the electronic structure of periodic systems, [51][52][53][54][55][56][57][58][59][60][61][62][63][64] particularly for transition metal oxides, and, as implemented in the CRYSTAL code, are computationally efficient for large systems. 65 This approach aims to develop a detailed model of interactions for this surface, prior to uncovering the role of defects as well as dependence on surface facet: a thorough investigation of the energetics has been performed, and the method adopted facilitates the analysis of the interactions between adjacent adsorbates.…”