Fig. 1. The structure, morphology, and composition analysis of the as-synthesized 2D (OCTAm)₂SnBr₄. (a) Experimental powder X-ray diffraction (PXRD) pattern. (b) Schematic representation of the crystal structure. (c) High-resolution TEM image, (d) scanning electron microscopy (SEM) image, (e) energy-dispersive X-ray spectroscopy (EDS) mapping image, and (f) the EDS spectrum of the 2D (OCTAm)₂SnBr₄ perovskites. Inset (c), the corresponding fast Fourier transform (FFT) image shown in (a).