Synthesis of High Fluorescent Carbon Dots by Laser Ablation of Bay Leaves in Biocompatible Solutions

A green dispersion of carbon dots (CDs) can be obtained by laser irradiation of bay leaves in liquids. The CDs synthesis is obtained using an Nd:YAG laser irradiating multilayered leaves placed into a phosphate-buffered saline (PBS) solution. The nanoparticle generation and their functionalization by the solution salts produce a high-intensity dispersion luminescence in the visible region, which is induced by UV excitation. The ablation uses ns pulses with 100 mJ energy employed with a 1 Hz repetition rate focused on the vegetal target. Plasma investigations, UV-visible, and IR optical spectroscopies were employed. Morphological, optical properties, and other characteristics of the dispersion are presented and discussed. The synthesized CDs showed an absorption peak at 274 nm to confirm the p-p* transition of the carbon core state, while the CD particles were spherical with a size of less than 10 nm. The CDs fluorescent emission is in the blue region, around 472 nm, upon excitation at 365 nm. The synthesized CDs showed stability over a long period (3 months). This study provides an inexpensive, green, and simple method for CDs synthesis for important biocompatible dispersion applications in different scientific fields, especially from biology to medicine.