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Figure 4. (A) In situ imaging using HAADF-STEM and characterizing with EDX reveals the variations in morphology and elemental migration of MAPbI₃ when exposed to rising temperatures. Reproduced with the permission of Ref.^[103] Copyright © 2016 Nature Research; (B) HAADF-STEM images of a PSC undergoing thermal degradation after beam damage. Reproduced with the permission of Ref.^[104] Copyright © 2016 American Chemical Society; (C) HAADF images and SAED patterns MAPbI₃ before and after the heat. Reproduced with the permission of Ref.^[105] Copyright © 2018 WILEY‐VCH Verlag GmbH & Co; KGaA (D) STEM images of a PSC sample based on MA (top line) and Cs/FA/MA (bottom line), undergoing in situ heating from room temperature to (85, 130, 150, and 170) °C. Reproduced with the permission of Ref.^[110] Copyright © Elsevier; (E) The left row shows the iDPC-STEM images demonstrating the surface degradation of a CsPbI3 nanocrystal within 1min at 200 °C. The middle row shows diagrams depicting the transformation process of CsPbI₃ into Pb and Cs₄PbI₆ under high-temperature conditions. The right row shows the iDPC-STEM images showing the Cs₄PbI₆ particles observed from the [211] orientation. Reproduced with the permission of Ref.^[97] Copyright © 2023 Springer Nature. EDX: Energy dispersive X-ray; SAED: Selected area electron diffraction; TEM: Transmission electron microscopy; STEM: Scanning TEM; iDPC: Integrated differential phase contrast; HAADF-STEM: High angle angular dark field-scanning transmission electron microscopy.