Femtosecond laser-induced size reduction of carbon nanodots in solution: Effect of laser fluence, spot size, and irradiation time

• Published in: Journal of applied physics 2015-02, Vol.117 (8)
• Main Authors: Nguyen, Vanthan, Yan, Lihe, Si, Jinhai, Hou, Xun
• Format: Article
• Language: English
• Subjects: ABLATION; Applied physics; CARBON; EFFICIENCY; EMISSION SPECTRA; Fluence; Functional groups; IRRADIATION; Laser ablation; LASER RADIATION; Lasers; NANOSCIENCE AND NANOTECHNOLOGY; PHOTOLUMINESCENCE; Polyethylene glycol; POLYETHYLENE GLYCOLS; QUANTUM DOTS; RED SHIFT; Size reduction; SURFACES; Thermometers
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4909506

Photoluminescent carbon nanodots (C-dots) with size tunability and uniformity were fabricated in polyethylene glycol (PEG200N) solution using femtosecond laser ablation method. The size distributions and photoluminescence (PL) properties of C-dots are well controlled by adjusting the combined parameters of laser fluence, spot size, and irradiation time. The size reduction efficiency of the C-dots progressively increases with decreasing laser fluence and spot size. The optimal PL spectra are red-shifted and the quantum yields decrease with the increase in C-dots size, which could be attributed to the more complex surface functional groups attached on C-dots induced at higher laser fluence and larger spot size. Moreover, an increase in irradiation time leads to a decrease in size of C-dots, but long-time irradiation will result in the generation of complex functional groups on C-dots, subsequently the PL spectra are red-shifted.