A facile room-temperature method for assembling colloidal copper sulfide (Cu.sub.2-xS) nanoparticles into highly electrically conducting calcogenide material layer films utilizes ammonium sulfide for connecting the nanoparticles, while simultaneously effecting templating surfactant ligand removal. The foregoing process steps transform an as-deposited insulating films into a highly conducting films (i.e., having a conductivity at least about 75 Scm.sup.-1). The methodology is anticipated as applicable to copper chalcogenides other than copper sulfide, as well as metal chalcogenides other than copper chalcogenides. The comparatively high conductivities reported are attributed to better interparticle coupling through the ammonium sulfide treatment. This approach presents a scalable room temperature route for fabricating comparatively highly conducting nanoparticle assemblies for large area electronic and optoelectronic applications.
STATEMENT OF GOVERNMENT INTEREST
 The research that lead to the embodiments as described herein, and the invention as claimed herein, was funded: (1) in part by the United States National Science Foundation under Agreement No. DMR-1149036; and (2) in part by the Energy Materials Center at Cornell (EMC.sup.2), an Energy Frontier Research Center funded by the United States Department of Energy, Office of Science, Office of Basic Energy Science, under Award Number DE-SC0001086. This work also made use of the Cornell Center for Materials Research (CCMR) shared facilities which are supported through the NSF MRSEC program (DMR-1120296). Device fabrication for the embodiments was performed at the Cornell Nanoscale Facility, a member of the National Nanotechnology Infrastructure Network, which is supported by the United States National Science Foundation under Grant ECS-0335765. The United States Government has rights in the invention as claimed herein.