2024 AIChE Annual Meeting
(416c) Role of Ligand-Induced Surface Stresses in Controlling Shapes of Ultrathin Colloidal Nanoplatelets
Authors
Dutta, S. - Presenter, École Normale Superieure de Lyon
Monego, D., Heidelberg Institute for Theoretical Studies
Grossman, D., École Polytechnique
Widmer-Cooper, A., University of Sydney
Abécassis, B., École Normale Superieure de Lyon
Ultrathin colloidal nanoplatelets (NPL) are ligand-coated sheet-like crystalline
objects with atomic scale thickness and possessing immense potential for
optoelectronic applications. In solutions NPLs can adopt a variety of shapes
such as cylinders, helicoids, and helical ribbons which play an important role
in determining their optical properties. However the fundamental physical
reasons behind the origin of multiple shapes remain poorly understood, hindering
our ability to engineer NPL shapes and subsequently control their optical
properties.
Here we use a combination of experiments, simulation, and theory to show that
the interaction of the adsorbed ligands with the crystal surface leads to
surface stresses that differ between the top and bottom surfaces and eventually
forces the NPL to its ultimate deformed shape. The deformed shape is dictated
by the NPL aspect ratio, thickness, orientation of the crystal with respect to
the edges, and the ligand-crystal interaction, though most of the molecular
details can be lumped into the spontaneous curvature. Furthermore, NPLs display
a smooth transition between helicoids and helical ribbons beyond a certain
critical width, a key feature of geometrically frustrated assemblies.
objects with atomic scale thickness and possessing immense potential for
optoelectronic applications. In solutions NPLs can adopt a variety of shapes
such as cylinders, helicoids, and helical ribbons which play an important role
in determining their optical properties. However the fundamental physical
reasons behind the origin of multiple shapes remain poorly understood, hindering
our ability to engineer NPL shapes and subsequently control their optical
properties.
Here we use a combination of experiments, simulation, and theory to show that
the interaction of the adsorbed ligands with the crystal surface leads to
surface stresses that differ between the top and bottom surfaces and eventually
forces the NPL to its ultimate deformed shape. The deformed shape is dictated
by the NPL aspect ratio, thickness, orientation of the crystal with respect to
the edges, and the ligand-crystal interaction, though most of the molecular
details can be lumped into the spontaneous curvature. Furthermore, NPLs display
a smooth transition between helicoids and helical ribbons beyond a certain
critical width, a key feature of geometrically frustrated assemblies.
Ref: Monego et al (2024) Ligand-induced incompatible curvatures control ultrathin nanoplatelet polymorphism and chirality, Proc. Natl. Acad. Sci. U.S.A., 121, e2316299121.