Upon mixing with 1.00 mol% Au/ZnO NPs, the surface becomes a relatively rough covering with fine white spots of NPs. The distribution of these spots on the Au interdigitated electrode surface is quite uniform, and the density of white spots increases accordingly with increasing content of NPs (Figure  4b, c, d). The results confirm the homogenous dispersion of 1.00 mol% Au/ZnO NPs in the P3HT matrix and its conformal coating on the substrate. In addition, the specific surface area of the composite film should be increased with increasing content of 1.00 mol% Au/ZnO NPs. Figure 4 FE-SEM images.

(a) P3HT. (b-d) P3HT:1.00 mol% Au/ZnO Palbociclib molecular weight NPs sensing films with the mixing ratios of 3:1, 2:1, and 1:2, respectively, on an Al2O3 substrate with interdigitated Au electrodes. The cross-sectional AZD6738 clinical trial FE-SEM images along with EDX analyses of P3HT and P3HT:1.00 mol% Au/ZnO NPs (4:1) composite sensing films on an Al2O3 substrate with interdigitated Au electrodes after sensing test at room temperature in dry air are illustrated in Figure  5. It can be seen that the P3HT film is a smooth and solid layer (Figure  5a, b, c), while the composite film demonstrates porous asperities of the nanoparticle-polymer mixture (Figure  5d, e, f). The thicknesses of P3HT and composite films are estimated in the same range of 6 to 8 μm. The elemental composition on the surface and across P3HT and P3HT:1.00 mol% Niclosamide Au/ZnO NP

layers is demonstrated in the EDX spectra and line scan profiles (Figure  5b, c and 5e, f, respectively). It confirms that the P3HT film contains only oxygen (O), carbon (C), and sulfur (S) and the P3HT:1.00 mol% Au/ZnO NP layer has one additional element of zinc (Zn) while the gold (Au) loaded element cannot be observed due to its very low content. In addition, the line scan profiles indicate that elemental compositions through the films are quite uniform. Figure 5 FE-SEM micrographs of the cross-sectional structure. (a) P3HT. (d) P3HT:1.00 mol% Au/ZnO NPs sensing films on an alumina substrate.

(b, e) Corresponding EDX. (c, f) Corresponding line scan profiles. Atomic force microscopy (AFM) was employed to quantitatively investigate the morphology of P3HT and P3HT:1.00 mol% Au/ZnO NPs (4:1) composite sensing films drop casted on the Al2O3 substrate (Figure  6). The results indicate that the film surfaces are quite uniform, containing only tiny defects within a scan area of 20 μm × 20 μm. The average surface roughness of P3HT and the P3HT:1.00 mol% Au/ZnO NPs film is calculated from AFM data to be 130.1 and 135.2 nm, respectively. In addition, the composite film exhibits a relatively sharp granular morphology with a uniform grain size of approximately 80 to 100 nm, suggesting the presence of a nanosized grain structure in the composite sensing film due to the addition of 1.00 mol% Au/ZnO NPs. Figure 6 AFM morphology. (a) P3HT. (b) P3HT:1.