Fig. 3: Calculated electronic and defect properties of the three interfaces formed by intragrain PbI2 impurity and perovskite phase.
From: Intragrain impurity annihilation for highly efficient and stable perovskite solar cells
a–c The charge density corresponding to the VBM and CBM, the total DOS of the PbI2-perovskite interfaces along perovskite (01\(\bar{1}\)), (011), and (001) plane correlated to atomic resolution STEM-HAADF images, respectively. The cyan, black, and purple spheres denote FA/Cs, Pb, and I atoms, respectively, and the yellow areas denote the computed charge density. d–f Point defects of perovskites including vacancies, interstitials, and anti-sites. Considering the progression of the structural transition, I, Pb, Cs/FA interstitials, and I vacancies are focused in this study. The charge density (yellow area) of the shoulder peak near the band edges and total DOS for PbI2-perovskite interfaces corresponds to (a–c) with one I interstitials (per supercell), respectively. The I interstitials per supercell is highlighted by the red dashed circle.
