Fig. 2. Optical properties of 2D tin bromide perovskites. (a) Photograph of 0.5 L of 2D (OCTAm)2SnBr4 colloidal solution under room light (left) and UV light (right). (b) UV-vis absorption and PL excitation (EX) and PL emission spectra (EM) of the samples shown in (a). (c) Three-dimensional excitation–emission matrix (EEM) fluorescence spectrum. (d) The graph of absolute PL QYs under different excitation wavelengths. (e) Time-resolved PL decay and fitting curves of the PL emission at 600 nm with an excitation wavelength of 340 nm. (f) Stability study of 2D (OCTAm)2SnBr4 monitored by the PL QY changes as a function of exposure time (0–240 days in ambient air and humidity).
