Superstructures from lead sulfide quantum dots

ABSTRACTThe superstructures of different morphology (superlattices and supercrystals) are obtained by self-organization of lead sulfide quantum dots (QDs) on a substrate. In contrast to the SAXS patterns of isolated QDs in solutions, the X-ray intensity from ordered superstructures is modulated by the interference from the QDs in SLs or SCs leading to occurrence of the intense peaks at small scattering angles. By indexing the peaks in the SAXS patterns it is concluded that QD SLs are close-packed QD ensembles with the lattice parameter close to the dot diameter and QD SCs have primitive orthorhombic crystal lattice. Absorption and photoluminescence bands of superstructures are also analyzed.