Methods. The morphology of the nanoparticles was examined by transmission electron microscopy (TEM) using a JEOL JEM-2100 (JEOL GmbH, Eching, Germany) at an acceleration voltage of 200 kV. The samples were prepared by placing a drop of the diluted nanoparticles solution on the carbon-coated copper grids and left to dry under ambient conditions. UV-vis-NIR spectra were recorded using a Lambda 650 spectrophotometer supplied by PerkinElmer.SERS spectra have been recorded using a confocal Raman microscope (WITec 300α) equipped with an upright optical microscope. For Raman excitation, laser light at λ = 488, 532, 633, and 785 nmwas coupled into a single-mode optical fiber and focused through a 50× objective (Olympus MPlanFL N, NA = 0.75) to a spot size of about1000 nm. The laser power was kept at 1 mW at the focal plane for all wavelengths, and the integration time was set to1 s. The kinetics were followed between 5 to 10 minutes for each sample, i.e., each curve is based on 300 to 600 different spectra. Each sample was measured at least three times. To check the behavior of the modified substrate with temperature, a micro temperature controller with an extended temperature range substrate (VAHEAT, Interherence GmbH). The black gold films were deposited over the heating element, and the temperature was varied from room temperature to 122 °C, the Raman spectra were measure with low intensity laser incidence (100 µW) in order to only induce the reaction by temperature and not by the light irradiation. A long working distance 50× objective was used to avoid contamination of the objective lens with possible volatile compounds emitted by the sample.