Fig. 1.

a Schematic representation of the film crystallization process of an LTAG-based FAMAPbI₃ perovskite layer. b XRD patterns of the as-formed films obtained using the control process and the LTAG method. &, α, δ, ∇ Mean characteristic diffraction signals of the PbI₂, black perovskite, yellow perovskite phases, and intermediate phase, respectively. c FTIR spectrum of the as-formed film powers using the control process and the LTAG method and for postannealed FAMAPbI₃ film. d XRD patterns of annealed perovskite layers prepared without (control) and with LTAG treatment (at 30, 50, and 70 °C)