Fabrication of luminescent silicon carbide nanoparticles by pulsed laser synthesis in liquid

The capabilities of liquid-assisted laser ablation technique with additional laser irradiation of solutions for the synthesis of SiC nanocrystals (NCs) have been investigated. Nanocrystalline particles of silicon carbide were synthesized by laser irradiation of the mixture of Si and C colloidal solutions using nanosecond and femtosecond laser radiation. For optimization of the conditions for the binary nanoparticles (NPs) formation, the characterization of inner structure, phase composition and morphology was performed by means of high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), X-ray photoelectron (XPS), Raman and Fourier-transform infrared (FTIR) spectroscopy and correlation of NPs properties with laser irradiation conditions were found. The characterization results proved the formation of near-spherical SiC NCs which exhibited photoluminescence (PL) in the broad spectral region of 350–600 nm. The origin of the observed photoluminescence is attributed to quantum confinement in small NCs, radiative recombination of photogenerated charge carriers, surface defects or silicon oxycarbide phases. The developed simple approach enables synthesis of colloidal SiC NPs that potentially satisfy the requirements of good dispersibility, stability and efficient PL for applications in biological labeling.