Synthesis of broad photoluminescence carbon nanodots by femtosecond laser ablation in liquid

Carbon nanodots (C-dots) with broad emissions when excitation wavelength changes in a large region are suitable for a broad range of applications, including optical down-conversion devices, bioimaging, and biosensors by selecting different excitation wavelengths without changing their structure. Herein, C-dots exhibiting broad photoluminescence from blue to green regions with strong excitation-dependence have been synthesized via femtosecond laser ablation in ethylenediamine solution. Detailed characterization showed that abundant surface functional groups, such as C-N, C-H, and C-O have been created on the surface of C-dots, which can efficiently introduce new emission centers on the surface site and result in the broad emissions.