Low polydispersed copper-sulfide nanocrystals derived from various Cu–alkyl amine complexes

Abstract

Copper-sulfides, Cu 2− x S nanocrystals (NCs) have been synthesized using the reaction between a Cu–alkyl amine complex and a sulfur/1-dodecanethiol. Here, 1-dodecanthiol plays an important role to reduce the reaction temperature of sulfuration. The Cu/S composition (the Cu-defect density) of Cu 2− x S NCs depends on the stability of Cu–alkyl amine complex. XPS analyses reveal that the substance of Cu-defect is attributed to an introducing of Cu + 2S 2− 2 species. There is a good correlation between an intensity of a near IR absorption peak and a Cu-defect density estimated by XPS analyses. These results demonstrate that optical properties of Cu 2− x S NCs in a near IR region are tunable.