Fig. 1. Reduction of residue stress via LASs.

a–d PFQNM-AFM mapping of perovskite thin films. Young’s Modulus maps of perovskite film without (referred as control sample) (a) additives, [C₄mim]⁺[C₀SO₄]⁻ (b), [C₄mim]⁺[C₁SO₄]⁻ (c) and [C₄mim]⁺[C₈SO₄]⁻ (d) treated films. The colored scale bar represents the magnitude of modules. e The box plot of the YM values across the whole images (red) and separately for the regions identified as GBs (navy) or as GIs (blue). The box plot denotes the median (center line), 75th (top edge of the box) and 25th (bottom edge of the box) percentiles. The colored curves are the connecting line corresponding to the mean of the statistical data points. f Temperature-dependent (001) d–spacing of control, [C₄mim]⁺[C₀SO₄]⁻ and [C₄mim]⁺[C₈SO₄]⁻ treated films.