Comprehensive modeling of band gaps and absorption spectra of complex semiconductors for solar applications

The performance of photoabsorbing materials is closely related to their band gaps and absorption spectra. In the fields of solar cells and photocatalysis, search for novel materials is ongoing. To identify optimal compounds, a modelling approach yielding accurate predictions for their electronic and optical properties is highly desirable. We recently applied the quasiparticle self-consistent QSGW method, efficiently accounting for the vertex correction, to study the electronic structure of halide perovskites and complex oxides. In the calculations, we included effects such as spin-orbit coupling, electron-hole interaction, magnetic ordering, nuclear quantum motions, and thermal vibrations. I will show that when an accurate electronic structure method is applied, and the significant effects are correctly accounted for, the band gaps and absorption spectra of complex materials can be reliably determined.