To disclose the effect of molecular arrangement on oxidation stability, solar experiments were performed on SFDBA in three different aggregation states under sunlight for different irradiation times. The corresponding photoluminescence (PL) spectra and digital photos of the samples under UV illumination are shown in Figure 3a-c. With the sunshine duration increasing, the emission peaks of SFDBA in dilute solutions become wider and shift from the initial 420 nm to 429 nm, 483 nm, 547 nm, 556 nm, indicating the complicated composition of the oxidation intermediates and products (Figure 3a). The changes in the emitting color from the digital
Figure 2 The molecular structure, arrangement, and morphology analysis of SFDBA microcrystals. a) The crystal molecular structure of SFDBA. b) An interdigital lipid bilayer-like dimer. c) Layer-by-layer arrangements of SFDBA molecules viewed from b -axis. d) The molecular arrangements and supramolecular interactions in bcplane. e) SEM, f) TEM, and g) AFM images of SFDBA microcrystals. Inset in (f): in upper left is the corresponding SAED pattern performed from [100] zone-axis; in bottom left is the cartoon diagram of the microcrystal with two major crystal faces indexed. Inset in (g): the cross-sectional profile of a single SFDBA microcrystal marked by a red dotted line. h) XRD patterns of the as-prepared SFDBA microcrystals (top) and the standard powder spectrum based on the single crystal data by using the MERCURY software (bottom).