Fig. 2: Atomic-imaging of the loss of MA⁺ and intermediate phase.

a HRTEM image acquired at 0.7 e Å⁻². ‘I’, ‘II’ and ‘III’ columns correspond to Pb²⁺-I⁻, I⁻, and MA⁺ columns respectively. Scale bar, 3 Å. b Structural model of tetragonal MAPbI₃. c HRTEM image acquired at 10.5 e Å⁻². d Intensity ratio of ‘III’ to ‘I’ column with increased doses. Nine data points of ‘III’ and ‘I’ type columns are used to obtain nine intensity ratios at each dose. The error bars represent standard deviations. e HRTEM image acquired at 28.0 e Å⁻². f Structural model of MA_0.5PbI₃. The squares indicate \({{{\mbox{V}}}}_{{{\mbox{MA}}}}^{-}\).