Preparation of gold nanoparticles using low-temperature heating of the dry residue of a droplet of an HAuCl4 solution in air.

In the present study, by heating a quartz glass substrate having the dry residue of a 10 µL droplet of a solution of HAuCl4 and a counter substrate facing to the dry residue from room temperature to one hundred and several tens of degrees Celsius in 20 min in air, highly dense gold nanoparticles were produced on the counter substrate. A gold nanoparticle substrate produced by this simple method was utilized as a substrate for surface-enhanced Raman scattering analysis.