Fig. 3: Characterization of IC-LIG structures on wood: morphological and structural analysis.

a Image showing lased and pristine ink-coated spruce veneer from the cross section perspective. SEM images of (b) pristine and (c) lased ink-coated spruce. The inset d is a magnified image of the upper surface showing its nanostructure. In c, crosses of different colors indicate the typical Raman measurement points on samples treated with high fluence parameters. The corresponding Raman spectra are shown in e. The top view optical image in f compares uncoated (left) with ink-coated (right) spruce after laser treatment. g, h SEM images (top view) showing the multi-hierarchical porosity of lased ink-coated spruce. i–k TEM images of the iron-carbon composite. The dark spots are due to the iron-rich phase. Scale bars: a 200 µm, b and c 50 µm, d 1 µm, f 10 mm, g 100 µm, h 25 µm, i 20 nm, j, k 10 nm.