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![Homojunction perovskite solar cells: opportunities and challenges](https://image.oaes.cc/ad4c7d93-f5b4-46ed-975a-7b415aed57cf/4403.fig.6.jpg)
Figure 6. Preparation process, device performance and structure diagram of graded perovskite homojunction. (A) Schematic illustration of the fabrication process of mixed Pb/Sn, Pb‐based and graded Pb/Sn for graded perovskite homojunction. Reproduced with permission from Sun et al.[49]. (B) Preparation process and material structure model of perovskite. (C) Schematic band diagram of perovskite films and quadruple-cation PSCs. (D) Performance of cells with 2% PMAI and without PMAI. Reproduced with permission from Xiang et al.[50]. (E) Graded band alignment homojunction structure in solar cells. Reproduced with permission from Yuan et al.[51]. CBM: Conduction band minimum; VBM: valence band maximum.