Figure 3. Results of modelling of vapour-response selectivity of a bio-inspired six-lamellae nanostructure with a variable extinction coefficient k.

(a) Nanostructure design with a distribution of adsorbed vapours (n=1.3, 1.4 and 1.5; d=5, 10 and 15 nm) over individual lamella 1–6. (b,d) Examples of reflectance spectra with k=0 and 0.05, respectively. (c,e) PCA scores plots with k=0 and 0.05, respectively. Numbers of each arm in (c,e) correspond to the lamella (L) of the six-lamellae stack. Vapour discrimination in (c) was limited to confined effects of symmetrical lamella and resulted only in three resolved arms; contributions of PCs: 53.1%, 27.1% and 17.0%, for PC₁–PC₃, respectively, capturing 97.2% of the total variance. A complete vapour discrimination in (e) was due to resolved effects of non-zero lamella absorption, resulting in all six resolved arms; contributions of PCs: 47.4%, 22.0% and 13.5%, for PC₁–PC₃, respectively, capturing 82.9% of the total variance.