posted on 2023-12-12, 12:40authored byPascal Rusch, Stefano Toso, Yurii P. Ivanov, Sergio Marras, Giorgio Divitini, Liberato Manna
In an effort to extend the library of colloidal heterostructures
based on halide perovskites, we report here the synthesis of CsPbBr3–PbxBiySz nanocrystal dimers. Their synthesis
is adapted from an earlier established cluster-based approach for
perovskite–chalcohalide CsPbBr3–Pb4S3Br2 heterostructures. However, the simple
introduction of bismuth alters the composition of the non-perovskite
domain from what would have been a Pb4S3Br2 chalcohalide domain (in the absence of Bi) to a mixed lead–bismuth
chalcogenide domain, that is, not incorporating halide ions. Our investigation
of the growth dynamics of these CsPbBr3–PbxBiySz heterostructures, performed by in situ optical spectroscopy
and ex situ electron microscopy, suggests the existence of an intermediate
state where the early formed perovskite domain is partially consumed
to feed the growth of the chalcogenide domain. Remarkably, their resulting
complex shape can be resolved by advanced electron microscopy and
even reconstructed from a tomographic series of images. It is found
that these unique heterostructures comprise two distinct anisotropic
domains: an elongated lead–bismuth chalcogenide rod attached
to a prismatic perovskite core.