Photoluminescence (PL) spectra of drop-casted CNx films are shown in Figure . The PL of R-CNx is spectrally broader and appears red-shifted compared to the benchmark material Y-CNx. Fitting the steady-state PL spectra of both materials to a sum of two Gaussian peaks reveals that the apparent spectral broadening of the R-CNx spectrum is due to the increase of a low-energy emission component (sub-peak B) below 2.5 eV.