Fig. 1. C-dot characterization. (A) PL emission spectra of the Lys C-dots upon excitation at different wavelengths (330–370 nm). (B) Representative AFM image showing Lys C-dots. The FTIR spectra (C) of the Lys C-dots. The peaks at ∼3340 cm⁻¹, 2935 cm⁻¹, and 1560 cm⁻¹ are ascribed to N–H stretching, and the peak at ∼1068 cm⁻¹ is ascribed to C–N stretching.