fig4

Figure 4. Schematic band diagrams of energy-level alignment. (A) Energy levels of recently reported CsPbI_xBr_3-x (0 ≤ x ≤ 3) films and highly efficient transport layers according to refs^[144-149], which were mainly obtained from absorption spectra and photoelectron spectroscopy. Note that the valence and conduction band levels as well as the work function may vary depending on the exact stoichiometry but also on the mode of preparation and surface treatments. Reprinted with permission^[143]. Copyright 2022, John Wiley and Sons. (B) Schematic diagram of PSC without (central panel) and with (right panel) CPS treatment. The open red circles represent V_X sites. Reprinted with permission^[150]. Copyright 2021, John Wiley and Sons. (C) Schematic band diagram of perovskite/HTL (i.e., Cs_0.06FA_0.79MA_0.15Pb(I_0.85Br_0.15)₃ and Spiro-OMeTAD) without and with interfacial dipole pointing towards HTL. Note, a rigid energy shift of the HOMO and the LUMO of the HTL was assumed caused by the change in E_Vac after CPS treatment. Reprinted with permission^[150]. Copyright 2021, John Wiley and Sons.