Electronic Structure of Bi-Activated Luminescent Compounds and Pure Bismuth Photocatalytic Compounds

The trends in electronic structure of Bi³⁺ and Bi²⁺ as luminescent dopant in wide bandgap inorganic compounds and that of pure Bi-compounds for photocatalytic splitting of water are explored by determination of vacuum referred electron binding energies. Spectroscopic data combined with the chemical shift model from the luminescence field and data on flatband potentials in electrochemistry provide most of the needed data. Occasionally data from photoelectron spectroscopy is used. The trends in VRBE of Bi³⁺ and Bi²⁺ ground state and excited state levels resemble that of Ce³⁺ and Eu²⁺ lanthanides. To some extend a pure Bi-compound can be regarded as a 100% Bi³⁺ doped La-compound. This all will be demonstrated and an overview on Bi electronic structure is presented. Comparison of electronic structure for Bi as luminescent dopant in inorganic compounds with pure Bi-compounds entails also a comparison of two disciplines in electro-chemistry, that of luminescence materials and of photo-catalytic compounds.