Fig. 2: Dynamic tracing and optical characterization of perovskite QDSMs.
From: Cooperative excitonic quantum ensemble in perovskite-assembly superlattice microcavities
a TEM image of monodisperse CsPbBr3 cubic QDs. b–e TEM images of the evolution of monodisperse QDs (a) self-assembling into closely packed SC (b) and finally to the rectangular QDSM (e) via low-temperature aging and drying-mediated methods. Rows of dots capped with oleylamine and oleic acid arrange themselves along the crystalline axis (b) and finally form sharp edges and regular shape (e). c is the annular TEM images of the cuboid QDSM and d is a close-up view of the red dotted box in c. f PL spectra of different structures. g PL spectra of the cavity-enhanced SF effect from a QDSM at 77 K. Inset: the simulated field distribution of the whispering gallery mode, L1 and L2 are long side and short side of the QDSM, respectively. h Power dependence of the PL intensity in cavity mode. Inset: Lorentz fitting of the cavity mode. i The resonant optical modes of QDSMs with different sizes. Multimode lasing can be obtained and the spacing between two adjacent modes decreases with the increasing of cavity size.
