Preparation of Substrates. Before film deposition, the desired substrates were treated in an air plasma (Harrick Plasma PDC-002) for 2 min, yielding hydrophilic surfaces. GO/TNC Film Deposition. The desired substrate was placed on a spin-coater (Suss MicroTec LabSpin 6 TT) and constantly rotated at 3000 rpm. First, 25 µL of a methanolic/aqueous GO solution was applied to the rotating substrate. After 30 s, the deposition step was repeated. After 30 s, 25 µL of the desired TNC/chloroform solution was deposited onto the rotating substrate, followed by the deposition of 2×25 µL GO solution, again each deposition step spaced by a 30 s delay time. This sequence was repeated 3 -10 times, depending on the desired film thickness. For film deposition on QCMs, the substrates were placed slightly off-center on the spin-coater, to avoid accumulation of the material in the central active area of the sensor. The QCMs were coated on one side.