  The colloidal synthesis of large thin two-dimensional (2D) nanosheets is
fascinating but challenging, since the growth along the lateral and vertical
dimensions need to be controlled independently. In-plane anisotropy in 2D
nanosheets is attracting more attention as well. We present a new synthesis for
large colloidal single-crystalline SnS nanosheets with the thicknesses down to
7 nm and lateral sizes up to 8 um. The synthesis uses trioctylphosphine-S
(TOP-S) as sulfur source and oleic acid (with or without TOP) as ligands. Upon
adjusting the capping ligand amount, the growth direction can be switched
between anisotropic directions (armchair and zigzag) and isotropic directions
("ladder" directions), leading to an edge-morphology anisotropy. This is the
first report on solution-phase synthesis of large thin SnS NSs with tunable
edge faceting. Furthermore, electronic transport measurements show strong
dependency on the crystallographic directions confirming structural anisotropy.
