As a reference, a LP-NC film from cytosine without pyrrolic nitrogen was prepared, which did not show any sensing response (Figure ). Although laser-treatment of cytosine produces highly-nitrogen doped LP-NC films with similar resistivity and morphology, the inherent absence of pyrrolic N in the precursor only generates non-active N-sites. Noteworthy, the influence of the charge carrier properties of the LP-NC on sensor performance, tested by Hall measurements, is negligible (Figure ).