Fig. 5From: Carbon quantum dots as a tracer of water seepage sources and pathways in grottoesa PL spectra of CQDs with excitation wavelengths ranging from 300 to 500 nm, inset: normalized PL spectra, b PL spectra of CQDs with concentrations ranging from 10−1 C0 to 10−3 C0, λex = 400 nmBack to article page