Computational discovery of electronic materials with structural prediction
This thesis examines structure-property relationships with a focus on two
promising chemical areas for conductive applications, copper chalcogenides and lone pair containing materials. At the intersection of these two chemical spaces a structural prediction method is used to examine the Cu-Sn(II)-O ternary space for which no stoichiometric ternary is known. The predicted structures are found to have very high thermodynamic instability to competing phases, and relationships between structure and stability are examined. The same method was used to successfully predict the known structures of SnO and Cu2PbO2. The electronic and optical properties are investigated with ab-initio DFT
for a pair of novel earth abundant mixed B-site cation delafossites. The properties of two recently discovered lone pair containing quaternary barium bismuth oxides are investigated and compared with collaborating experimental characterisation.
The CuM(2/3)Sb(1/3)O2 (M = Zn/Mg) delafossites are both found to have
high valence band effective masses and weak absorption of visible light, moving them away from potential application as photoconversion and p-type conductive materials. M(II) and Sb(V) s state incorporation to the conduction band is found to result in improved conduction band dispersion. Substitution of Nb and Ta into perovskite BaBiO3 is shown to successfully modulate band gaps and produce dispersive valence bands. Ba2BiTaO6 is indicated as a promising transparent conductor due to it’s 3.1 eV band gap and high potential p-type mobilities.
https://discovery.ucl.ac.uk/id/eprint/10157941/2/Thesis-ER-FINAL-corrected-05-10-2022.pdf