A metal sulfide nanocrystal manufactured by a method of reacting a metal
precursor and an alkyl thiol in a solvent, wherein the alkyl thiol reacts
with the metal precursor to form the metal sulfide nanocrystals, wherein
the alkyl thiol is present on the surface of the metal sulfide
nanocrystal, wherein the alkyl thiol is bonded to the sulfur crystal
lattice. A metal sulfide nanocrystal manufactured with a core-shell
structure by a method of reacting a metal precursor and an alkyl thiol in
a solvent to form a metal sulfide layer on the surface of a core, wherein
the alkyl thiol is present on the surface of the metal sulfide
nanocrystal, wherein the alkyl thiol is bonded to the sulfur crystal
lattice. These metal sulfide nanocrystals can have a uniform particle
size at the nanometer-scale level, selective and desired crystal
structures, and various shapes.