First-principles analysis of the optical properties of lead halide perovskite solution precursors

Lead halide perovskites (LHPs) are promising materials for opto-electronics and photovoltaics, thanks to favorable characteristics low manufacturing costs enabled by solution processing. In light of this, it is crucial assess the impact solvent-solute interactions on electronic optical properties LHPs their precursors. a first-principles work based time-dependent density-functional theory coupled with polarizable continuum model, we investigate set charge-neutral compounds chemical formula, PbX$_2$(Sol)$_4$, where X=Cl, Br, I, Sol six common solvents. We find that single-particle energies gaps depend halogen species as well solvent molecules, which also affect energy spatial distribution molecular orbitals, thereby impacting excitations. clarify dark states at absorption onset promoted electron-withdrawing solvents, show correlation between oscillator strength HOMO$\rightarrow$LUMO contribution Our results provide microscopic insight into LHP precursors, complementing ongoing experimental research these systems evolution photovoltaic thin films.