Fig. 3: Characterizations of the studied perovskite films.

a Cross-sectional SEM images. b XRD patterns. c Enlarged XRD areas (13.3–25°) with the calculated peak ratio of (001)/(111). d Strain analysis based on the 2θ-sin²φ method. e Dark I–V curves of the hole-only devices. f Steady-state PL spectra. g Time-resolved PL decays.