Fig. 3: Crystallographic analyses before and after the phase conversion.
From: Solid-phase hetero epitaxial growth of α-phase formamidinium perovskite
X-ray diffraction (XRD) patterns of the films a before and b after the phase conversion process. c High-resolution X-ray diffraction (XRD) patterns of the films after the phase conversion process. Inset shows the normalized (002) orientation peaks. d–g XRD pole figure measurements along the (001) orientation of the d control, e 1P, f 3P, and g 3F films. h Composition-dependent strain before phase conversion and crystallite size of the films before and after the phase conversion process. The strain was calculated using the Williamson-Hall method for the δ-FAPbI3 films. The δ-FAPbI3 crystallite sizes were calculated by the Williamson–Hall method, while the α-FAPbI3 crystallite sizes were extracted from the AFM images. i Steady-state photoluminescence (PL) and j time-resolved PL decay profile measurements of the corresponding films. Insets of i show peak intensity (left) and normalized PL spectra (right).
