Rhodamine 6g dye r6g

The chemicals used for the electrodeposition of Au nanostructures were gold (III) chloride trihydrate (HAuCl₄·3H₂O, ≥99.9%) and potassium hydroxide (KOH, ≥85.8%). These chemicals were purchased from Sigma-Aldrich (St. Louis, MO, USA) and Fisher Scientific (Hanover park, IL, USA), respectively. The substrates used for electrodeposition of the Au nanostructures were carbon cloth (AvCarb Material Solutions, 1071 HCB) and wet-proofed carbon paper (Toray, 060) purchased from Fuel Cell Store (College Station, TX, USA). The chemicals used for cleaning the substrates were acetone, hydrochloric acid (HCl, 36.5–38.0%), and nitric acid (HNO₃, 68.0–70.0%), purchased from Fisher Scientific. For SERS experiments, Rhodamine 6G dye (R6G, 99%) and paraoxon-ethyl (C₁₀H₁₄NO₆P, ≥90%) were purchased from Sigma-Aldrich. Deionized (DI) water was used for preparing all precursor and analyte solutions.

The chemicals used for metallic deposition included potassium tetrachloroplatinate(II) (K₂PtCl₄, ≥99.9%), sodium tetrachloropalladate(II) (Na₂PdCl₄, 98%), and cetyltrimethylammonium bromide (C₁₉H₄₂BrN, ≥99.9%) purchased from Sigma–Aldrich (Milwaukee, WI, USA), sodium dodecyl sulfate (C₁₂H₂₅NaO₄S, ≥99%) from Fisher Scientific (Hampton, NH, USA), which were used as received. Hydrofluoric acid (HF, 48–51%) was purchased from Thermo Fisher Scientific (Waltham, MA, USA). For SERS experiments, Rhodamine 6G dye (R6G, 99%) and paraoxon-ethyl (C₁₀H₁₄NO₆P, ≥90%) were purchased from Sigma–Aldrich (Milwaukee, WI, USA). All solutions were prepared using deionized (DI) water. HF was contained in a polypropylene beaker for experimental use. The substrate was Si (100) wafer (4″, single-crystalline, n-type, ρ = 3–9 Ωcm) purchased from El-Cat Inc. (Ridgefield Park, NJ, USA). Prior to deposition, Si wafer was cleaved into 1.5 cm × 1.5 cm² pieces. The chemicals used for cleaning Si substrate were acetone and ethanol (100%, 200 proof).