Anion-mediated electronic effects in reducible oxides: Tuning the valence band of ceria via fluorine doping

Fluorine can be substitutionally incorporated into oxide lattices without distorting these up to very high concentrations. Of all the possible anion dopants, this makes fluorine a fascinating choice for tuning the electronic structure of oxides. Our previous work on fluorine doping focused on the process itself and the associated chemistry. However, the actual electronic structure implications are still poorly understood. In our latest paper in the Journal of Physical Chemistry, we reveal the bond between the cation and fluorine dopant to be partially covalent. The partial covalent interaction is in contrast to the usual simplification of fluorine bonding to purely ionic in character. The finding extends fluorine bonding outside of the realms of innocent n-doping and allows for further functionalization of oxides. The paper has been selected as an Editor’s pick and is featured on the front cover of the journal!