Fig. 2

Influence of applied electric field on the SERS spectra of PATP on the template. a SERS measurements of PATP on the FF-PNT/Ag NP template at different electric fields strengths, applying voltages from 0–10 V at 40 kHz AC with offset DC bias of 200 mV. b, c Corresponding Raman band intensity at 1334 cm⁻¹ (assigned to PNTP) as a function of voltage. b Critical threshold voltage ~4 V required for the formation of PNTP. Inset illustrates SERS intensity with offset DC bias. c The window of 10–20 V is optimal for PNTP product yield via photocatalysis, with SERS intensity reducing above ~25 V. d Normalized SERS spectra, comparing a fully relaxed control sample at zero field (red) to the spectrum recorded with applied field (blue). e Plot of SERS signal strength intensity vs. AC electric field, showing manipulation of the product yield achieved by utilizing an electric field with a voltage of 10 V and an offset DC bias of 300 mV (conditions that yield PNTP) vs. a weaker electric field formed using a voltage of 4 V and an offset DC bias of 100 mV (conditions that yield PATP). f Schematic illustration of the transformation and switch of the product formation of PATP to PNTP