Ag/Ag₂S heterodimers: tailoring the metal–semiconductor interface in a single nanoparticle

Heterodimers are conjoined particles of two inorganic materials, and they are generally synthesised in multiple steps. But, the multi-step syntheses are less effective because of the low yield, long reaction time, labour intensive process and complexity in the synthesis and thus not ideal for scale up. Herein, we have demonstrated single-step, one-pot syntheses for two different types of Ag/Ag₂S heterodimers. Two types of heterodimers were obtained while varying stoichiometry in the reaction of AgNO₃ with sulphur in the presence of hexamethyldisilazane (HMDS) at 140 °C. To the best of our knowledge, this was the first demonstration of single-step process to synthesise Ag/Ag₂S heterodimers. Heterodimers had dumbbell shape with both metal and semiconductor domains in single particle which were constructed by spherical Ag and Ag₂S nanoparticles. Ag (2 0 0) and Ag₂S (0 2 2) planes associated to form heterodimers. The presence of metal–semiconductor interfaces was confirmed by HRTEM and UV analysis. Thus, we have demonstrated the HMDS-assisted synthesis as a promising method for direct synthesis of Ag/Ag₂S heterodimers.