The fate of organic species upon sintering of thiol-stabilised gold nanoparticles under different atmospheric conditions

Understanding and controlling the sintering behavior of gold nanoparticles is important for applications such as printed electronics, catalysis and sensing that utilise these materials. Here we examine the processes by which thiol-protected gold nanoparticles thermally sinter under a variety of atmospheres. We find that upon sintering, the surface-bound thiyl ligands exclusively form the corresponding disulfide species when released from the gold surface. Experiments conducted using air, hydrogen, nitrogen, or argon atmospheres revealed no significant differences between the temperatures of the sintering event nor on the composition of released organic species. When conducted under high vacuum, the sintering event occurred at lower temperatures compared to ambient pressures in cases where the resulting disulfide had relatively high volatility (dibutyl disulfide). Hexadecylthiol-stabilized particles exhibited no significant differences in the temperatures of the sintering event under ambient pressures compared to high vacuum conditions. We attribute this to the relatively low volatility of the resultant dihexadecyl disulfide product.

Automated summary

Understanding and controlling the sintering behavior of gold nanoparticles is crucial for various applications. Thiol-protected gold nanoparticles were found to exclusively form disulfide species upon sintering. The sintering event showed no significant differences in temperature or composition under different atmospheres, except for cases with high volatility disulfides. Hexadecylthiol-stabilized particles showed no significant differences in sintering temperature under different pressures.