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).