Figure 4.

Characterization of the thin films with the 2D/3D core–shell structure synthesized from a mixed precursor solution of 3D FASnI₃ and 2D PEA₂SnI₄ (top, center rows) and the TFT performances (bottom row): a) out‐of‐plane XRD patterns, b) in‐plane XRD patterns, SEM images of the thin films with 2D:3D mixing ratios of c) 1:2, d) 1:4, and e) 1:6; transfer curves of the TFTs fabricated from thin films with 2D:3D mixing ratios of f) 1:2, g) 1:4, and h) 1:6.