Highly uniform matchstick-like Ag2S–ZnS hetero-nanorods using dodecanethiol as a sulfur source

Abstract

A two-step colloidal synthesis of highly uniform Ag2S–ZnS matchstick-like hetero-nanorods, composed of Ag2S head and ZnS rod-like stem, is reported. Dodecanethiol is used as a sulfur source and a solvent. Ag2S nanocrystals are first prepared, act as a catalyst to grow anisotropic ZnS nanorods, and finally remain at the tip of the resultant nanorods, leading to Ag2S–ZnS hetero-nanorods with a matchstick-like shape. By decreasing the amount of Ag precursor (AgNO3), uniform ZnS nanorods without Ag2S catalytic heads can be prepared. The disappearance of Ag2S heads is attributed to the diffusion of Ag+ ions from Ag2S into the growing ZnS nanorods. These hetero-nanorods combine narrow band gap semiconductor Ag2S (bulk Eg=0.9–1.1eV) with wide band gap semiconductor ZnS (bulk Eg=3.77eV) and may be promising optical and/or optoelectronic materials.