1 research outputs found
Extraordinary Interfacial Stitching between Single All-Inorganic Perovskite Nanocrystals
All-inorganic cesium
lead halide perovskite nanocrystals are extensively studied because
of their outstanding optoelectronic properties. Being of a cubic shape
and typically featuring a narrow size distribution, CsPbX<sub>3</sub> (X = Cl, Br, and I) nanocrystals are the ideal starting material
for the development of homogeneous thin films as required for photovoltaic
and optoelectronic applications. Recent experiments reveal spontaneous
merging of drop-casted CsPbBr<sub>3</sub> nanocrystals, which is promoted
by humidity and mild-temperature treatments and arrested by electron
beam irradiation. Here, we make use of atom-resolved annular dark-field
imaging microscopy and valence electron energy loss spectroscopy in
a state-of-the-art low-voltage monochromatic scanning transmission
electron microscope to investigate the aggregation between individual
nanocrystals at the atomic level. We show that the merging process
preserves the elemental composition and electronic structure of CsPbBr<sub>3</sub> and takes place between nanocrystals of different sizes and
orientations. In particular, we reveal seamless stitching for aligned
nanocrystals, similar to that reported in the past for graphene flakes.
Because the crystallographic alignment occurs naturally in drop-casted
layers of CsPbX<sub>3</sub> nanocrystals, our findings constitute
the essential first step toward the development of large-area nanosheets
with band gap energies predesigned by the nanocrystal choiceî—¸the
gateway to large-scale photovoltaic applications of inorganic perovskites