Project title: Understanding of functionality of metal halide perovskites as optoelectronic materials through electronic structure analysis
Main applicant: Sergei Butorin, X-Ray Photon Science
Grant amount: SEK 4 140 000 for the period 2026-2030
The purpose of the project is to elucidate features of the electronic structure of metal halide perovskites (HaPs) which are linked to and influence optoelectronic properties of HaPs. The intention is to use advanced x-ray spectroscopic tools, such as high-energy-resolution fluorescence-detection x-ray absorption spectroscopy (HERFD-XAS) and resonant inelastic x-ray scattering (RIXS). The electronic structure will be probed in element-, site-, symmetry- and orbital-selective manner with an enhanced energy resolution. The following objectives are set for the proposed project: (i) Clarify the optoelectronic function of the organic cation by studying the conduction band of HaPs and unoccupied π-states of halide anion related to the halide anion-hydrogen bonds with the organic cation. This will be done for the varying crystallographic dimensionality, form of the sample and exchange of various cations and anions in the chemical formula; (ii) Establish the mechanism in the electronic structure allowing for a strong defect tolerance in HaPs by performing experiments under in-operando conditions; (iii) Improve theoretical methods to support the interpretation of the experimental data and enhance the predictive ability. In particular, establish and justify the use of efficient exchange correlation functionals in density functional theory for an accurate calculation of the band gap in HaPs when the spin-orbit coupling of the valence electrons is taken into account.
