ultrathin single-crystal pbs (lead sulfur) sheets with micro scale in x-, y- dimensions can be obtained using a hot colloidal synthesis method. compounds with linear chloroalkanes like 1,2-dichloroethane containing chlorine were used during the formation of pbs sheets. pbs ultrathin sheets probably resulted from the oriented attachment of the pbs nanoparticles in a two-dimensional fashion. the highly reactive facets were preferentially consumed in the growth process that led to the sheet-like pbs crystal growth.